diff options
Diffstat (limited to 'png.c')
| -rw-r--r-- | png.c | 2162 |
1 files changed, 1777 insertions, 385 deletions
@@ -1,7 +1,7 @@ /* png.c - location for general purpose libpng functions * - * Last changed in libpng 1.5.14 [January 24, 2013] + * Last changed in libpng 1.6.0 [February 14, 2013] * Copyright (c) 1998-2013 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) @@ -14,7 +14,7 @@ #include "pngpriv.h" /* Generate a compiler error if there is an old png.h in the search path. */ -typedef png_libpng_version_1_5_14 Your_png_h_is_not_version_1_5_14; +typedef png_libpng_version_1_6_0 Your_png_h_is_not_version_1_6_0; /* Tells libpng that we have already handled the first "num_bytes" bytes * of the PNG file signature. If the PNG data is embedded into another @@ -24,7 +24,7 @@ typedef png_libpng_version_1_5_14 Your_png_h_is_not_version_1_5_14; #ifdef PNG_READ_SUPPORTED void PNGAPI -png_set_sig_bytes(png_structp png_ptr, int num_bytes) +png_set_sig_bytes(png_structrp png_ptr, int num_bytes) { png_debug(1, "in png_set_sig_bytes"); @@ -62,7 +62,7 @@ png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check) if (start + num_to_check > 8) num_to_check = 8 - start; - return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check))); + return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check))); } #endif /* PNG_READ_SUPPORTED */ @@ -72,43 +72,34 @@ png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check) PNG_FUNCTION(voidpf /* PRIVATE */, png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED) { - png_voidp ptr; - png_structp p; - png_uint_32 save_flags; - png_alloc_size_t num_bytes; + png_alloc_size_t num_bytes = size; if (png_ptr == NULL) - return (NULL); - - p=(png_structp)png_ptr; - save_flags=p->flags; + return NULL; - if (items > PNG_UINT_32_MAX/size) + if (items >= (~(png_alloc_size_t)0)/size) { - png_warning (p, "Potential overflow in png_zalloc()"); - return (NULL); + png_warning (png_voidcast(png_structrp, png_ptr), + "Potential overflow in png_zalloc()"); + return NULL; } - num_bytes = (png_alloc_size_t)items * size; - - p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK; - ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes); - p->flags=save_flags; - return ((voidpf)ptr); + num_bytes *= items; + return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes); } /* Function to free memory for zlib */ void /* PRIVATE */ png_zfree(voidpf png_ptr, voidpf ptr) { - png_free((png_structp)png_ptr, (png_voidp)ptr); + png_free(png_voidcast(png_const_structrp,png_ptr), ptr); } /* Reset the CRC variable to 32 bits of 1's. Care must be taken * in case CRC is > 32 bits to leave the top bits 0. */ void /* PRIVATE */ -png_reset_crc(png_structp png_ptr) +png_reset_crc(png_structrp png_ptr) { /* The cast is safe because the crc is a 32 bit value. */ png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0); @@ -120,7 +111,7 @@ png_reset_crc(png_structp png_ptr) * trouble of calculating it. */ void /* PRIVATE */ -png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length) +png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length) { int need_crc = 1; @@ -137,10 +128,10 @@ png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length) need_crc = 0; } - /* 'uLong' is defined as unsigned long, this means that on some systems it is - * a 64 bit value. crc32, however, returns 32 bits so the following cast is - * safe. 'uInt' may be no more than 16 bits, so it is necessary to perform a - * loop here. + /* 'uLong' is defined in zlib.h as unsigned long; this means that on some + * systems it is a 64 bit value. crc32, however, returns 32 bits so the + * following cast is safe. 'uInt' may be no more than 16 bits, so it is + * necessary to perform a loop here. */ if (need_crc && length > 0) { @@ -148,18 +139,18 @@ png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length) do { - uInt safeLength = (uInt)length; - if (safeLength == 0) - safeLength = (uInt)-1; /* evil, but safe */ + uInt safe_length = (uInt)length; + if (safe_length == 0) + safe_length = (uInt)-1; /* evil, but safe */ - crc = crc32(crc, ptr, safeLength); + crc = crc32(crc, ptr, safe_length); - /* The following should never issue compiler warnings, if they do the + /* The following should never issue compiler warnings; if they do the * target system has characteristics that will probably violate other * assumptions within the libpng code. */ - ptr += safeLength; - length -= safeLength; + ptr += safe_length; + length -= safe_length; } while (length > 0); @@ -169,10 +160,10 @@ png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length) } /* Check a user supplied version number, called from both read and write - * functions that create a png_struct + * functions that create a png_struct. */ int -png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver) +png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver) { if (user_png_ver) { @@ -193,20 +184,23 @@ png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver) /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so * we must recompile any applications that use any older library version. * For versions after libpng 1.0, we will be compatible, so we need - * only check the first digit. + * only check the first and third digits (note that when we reach version + * 1.10 we will need to check the fourth symbol, namely user_png_ver[3]). */ if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] || - (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) || + (user_png_ver[0] == '1' && (user_png_ver[2] != png_libpng_ver[2] || + user_png_ver[3] != png_libpng_ver[3])) || (user_png_ver[0] == '0' && user_png_ver[2] < '9')) { #ifdef PNG_WARNINGS_SUPPORTED size_t pos = 0; char m[128]; - pos = png_safecat(m, sizeof m, pos, "Application built with libpng-"); - pos = png_safecat(m, sizeof m, pos, user_png_ver); - pos = png_safecat(m, sizeof m, pos, " but running with "); - pos = png_safecat(m, sizeof m, pos, png_libpng_ver); + pos = png_safecat(m, (sizeof m), pos, + "Application built with libpng-"); + pos = png_safecat(m, (sizeof m), pos, user_png_ver); + pos = png_safecat(m, (sizeof m), pos, " but running with "); + pos = png_safecat(m, (sizeof m), pos, png_libpng_ver); png_warning(png_ptr, m); #endif @@ -223,43 +217,145 @@ png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver) return 1; } -/* Allocate the memory for an info_struct for the application. We don't - * really need the png_ptr, but it could potentially be useful in the - * future. This should be used in favour of malloc(png_sizeof(png_info)) - * and png_info_init() so that applications that want to use a shared - * libpng don't have to be recompiled if png_info changes size. +/* Generic function to create a png_struct for either read or write - this + * contains the common initialization. */ +PNG_FUNCTION(png_structp /* PRIVATE */, +png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, + png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) +{ + png_struct create_struct; +# ifdef PNG_SETJMP_SUPPORTED + jmp_buf create_jmp_buf; +# endif + + /* This temporary stack-allocated structure is used to provide a place to + * build enough context to allow the user provided memory allocator (if any) + * to be called. + */ + memset(&create_struct, 0, (sizeof create_struct)); + + /* Added at libpng-1.2.6 */ +# ifdef PNG_USER_LIMITS_SUPPORTED + create_struct.user_width_max = PNG_USER_WIDTH_MAX; + create_struct.user_height_max = PNG_USER_HEIGHT_MAX; + +# ifdef PNG_USER_CHUNK_CACHE_MAX + /* Added at libpng-1.2.43 and 1.4.0 */ + create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX; +# endif + +# ifdef PNG_USER_CHUNK_MALLOC_MAX + /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists + * in png_struct regardless. + */ + create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX; +# endif +# endif + + /* The following two API calls simply set fields in png_struct, so it is safe + * to do them now even though error handling is not yet set up. + */ +# ifdef PNG_USER_MEM_SUPPORTED + png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn); +# endif + + /* (*error_fn) can return control to the caller after the error_ptr is set, + * this will result in a memory leak unless the error_fn does something + * extremely sophisticated. The design lacks merit but is implicit in the + * API. + */ + png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn); + +# ifdef PNG_SETJMP_SUPPORTED + if (!setjmp(create_jmp_buf)) + { + /* Temporarily fake out the longjmp information until we have + * successfully completed this function. This only works if we have + * setjmp() support compiled in, but it is safe - this stuff should + * never happen. + */ + create_struct.jmp_buf_ptr = &create_jmp_buf; + create_struct.jmp_buf_size = 0; /*stack allocation*/ + create_struct.longjmp_fn = longjmp; +# else + { +# endif + /* Call the general version checker (shared with read and write code): + */ + if (png_user_version_check(&create_struct, user_png_ver)) + { + png_structrp png_ptr = png_voidcast(png_structrp, + png_malloc_warn(&create_struct, (sizeof *png_ptr))); + + if (png_ptr != NULL) + { + /* png_ptr->zstream holds a back-pointer to the png_struct, so + * this can only be done now: + */ + create_struct.zstream.zalloc = png_zalloc; + create_struct.zstream.zfree = png_zfree; + create_struct.zstream.opaque = png_ptr; + +# ifdef PNG_SETJMP_SUPPORTED + /* Eliminate the local error handling: */ + create_struct.jmp_buf_ptr = NULL; + create_struct.jmp_buf_size = 0; + create_struct.longjmp_fn = 0; +# endif + + *png_ptr = create_struct; + + /* This is the successful return point */ + return png_ptr; + } + } + } + + /* A longjmp because of a bug in the application storage allocator or a + * simple failure to allocate the png_struct. + */ + return NULL; +} + +/* Allocate the memory for an info_struct for the application. */ PNG_FUNCTION(png_infop,PNGAPI -png_create_info_struct,(png_structp png_ptr),PNG_ALLOCATED) +png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED) { - png_infop info_ptr; + png_inforp info_ptr; png_debug(1, "in png_create_info_struct"); if (png_ptr == NULL) - return (NULL); + return NULL; + + /* Use the internal API that does not (or at least should not) error out, so + * that this call always returns ok. The application typically sets up the + * error handling *after* creating the info_struct because this is the way it + * has always been done in 'example.c'. + */ + info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr, + (sizeof *info_ptr))); -#ifdef PNG_USER_MEM_SUPPORTED - info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO, - png_ptr->malloc_fn, png_ptr->mem_ptr); -#else - info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); -#endif if (info_ptr != NULL) - png_info_init_3(&info_ptr, png_sizeof(png_info)); + memset(info_ptr, 0, (sizeof *info_ptr)); - return (info_ptr); + return info_ptr; } /* This function frees the memory associated with a single info struct. * Normally, one would use either png_destroy_read_struct() or * png_destroy_write_struct() to free an info struct, but this may be - * useful for some applications. + * useful for some applications. From libpng 1.6.0 this function is also used + * internally to implement the png_info release part of the 'struct' destroy + * APIs. This ensures that all possible approaches free the same data (all of + * it). */ void PNGAPI -png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr) +png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr) { - png_infop info_ptr = NULL; + png_inforp info_ptr = NULL; png_debug(1, "in png_destroy_info_struct"); @@ -271,46 +367,57 @@ png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr) if (info_ptr != NULL) { - png_info_destroy(png_ptr, info_ptr); - -#ifdef PNG_USER_MEM_SUPPORTED - png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn, - png_ptr->mem_ptr); -#else - png_destroy_struct((png_voidp)info_ptr); -#endif + /* Do this first in case of an error below; if the app implements its own + * memory management this can lead to png_free calling png_error, which + * will abort this routine and return control to the app error handler. + * An infinite loop may result if it then tries to free the same info + * ptr. + */ *info_ptr_ptr = NULL; + + png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); + memset(info_ptr, 0, (sizeof *info_ptr)); + png_free(png_ptr, info_ptr); } } /* Initialize the info structure. This is now an internal function (0.89) * and applications using it are urged to use png_create_info_struct() - * instead. + * instead. Use deprecated in 1.6.0, internal use removed (used internally it + * is just a memset). + * + * NOTE: it is almost inconceivable that this API is used because it bypasses + * the user-memory mechanism and the user error handling/warning mechanisms in + * those cases where it does anything other than a memset. */ - -void PNGAPI -png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size) +PNG_FUNCTION(void,PNGAPI +png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size), + PNG_DEPRECATED) { - png_infop info_ptr = *ptr_ptr; + png_inforp info_ptr = *ptr_ptr; png_debug(1, "in png_info_init_3"); if (info_ptr == NULL) return; - if (png_sizeof(png_info) > png_info_struct_size) + if ((sizeof (png_info)) > png_info_struct_size) { - png_destroy_struct(info_ptr); - info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); + *ptr_ptr = NULL; + /* The following line is why this API should not be used: */ + free(info_ptr); + info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL, + (sizeof *info_ptr))); *ptr_ptr = info_ptr; } /* Set everything to 0 */ - png_memset(info_ptr, 0, png_sizeof(png_info)); + memset(info_ptr, 0, (sizeof *info_ptr)); } +/* The following API is not called internally */ void PNGAPI -png_data_freer(png_structp png_ptr, png_infop info_ptr, +png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr, int freer, png_uint_32 mask) { png_debug(1, "in png_data_freer"); @@ -325,12 +432,11 @@ png_data_freer(png_structp png_ptr, png_infop info_ptr, info_ptr->free_me &= ~mask; else - png_warning(png_ptr, - "Unknown freer parameter in png_data_freer"); + png_error(png_ptr, "Unknown freer parameter in png_data_freer"); } void PNGAPI -png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, +png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask, int num) { png_debug(1, "in png_free_data"); @@ -395,8 +501,8 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, info_ptr->pcal_units = NULL; if (info_ptr->pcal_params != NULL) { - int i; - for (i = 0; i < (int)info_ptr->pcal_nparams; i++) + unsigned int i; + for (i = 0; i < info_ptr->pcal_nparams; i++) { png_free(png_ptr, info_ptr->pcal_params[i]); info_ptr->pcal_params[i] = NULL; @@ -409,7 +515,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, #endif #ifdef PNG_iCCP_SUPPORTED - /* Free any iCCP entry */ + /* Free any profile entry */ if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) { png_free(png_ptr, info_ptr->iccp_name); @@ -440,8 +546,8 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, if (info_ptr->splt_palettes_num) { int i; - for (i = 0; i < (int)info_ptr->splt_palettes_num; i++) - png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i); + for (i = 0; i < info_ptr->splt_palettes_num; i++) + png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, (int)i); png_free(png_ptr, info_ptr->splt_palettes); info_ptr->splt_palettes = NULL; @@ -452,13 +558,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, } #endif -#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED - if (png_ptr->unknown_chunk.data) - { - png_free(png_ptr, png_ptr->unknown_chunk.data); - png_ptr->unknown_chunk.data = NULL; - } - +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) { if (num != -1) @@ -477,7 +577,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, if (info_ptr->unknown_chunks_num) { for (i = 0; i < info_ptr->unknown_chunks_num; i++) - png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i); + png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, (int)i); png_free(png_ptr, info_ptr->unknown_chunks); info_ptr->unknown_chunks = NULL; @@ -500,7 +600,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, /* Free any PLTE entry that was internally allocated */ if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) { - png_zfree(png_ptr, info_ptr->palette); + png_free(png_ptr, info_ptr->palette); info_ptr->palette = NULL; info_ptr->valid &= ~PNG_INFO_PLTE; info_ptr->num_palette = 0; @@ -512,8 +612,8 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, { if (info_ptr->row_pointers) { - int row; - for (row = 0; row < (int)info_ptr->height; row++) + png_uint_32 row; + for (row = 0; row < info_ptr->height; row++) { png_free(png_ptr, info_ptr->row_pointers[row]); info_ptr->row_pointers[row] = NULL; @@ -530,29 +630,6 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, info_ptr->free_me &= ~mask; } - -/* This is an internal routine to free any memory that the info struct is - * pointing to before re-using it or freeing the struct itself. Recall - * that png_free() checks for NULL pointers for us. - */ -void /* PRIVATE */ -png_info_destroy(png_structp png_ptr, png_infop info_ptr) -{ - png_debug(1, "in png_info_destroy"); - - png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); - -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED - if (png_ptr->num_chunk_list) - { - png_free(png_ptr, png_ptr->chunk_list); - png_ptr->chunk_list = NULL; - png_ptr->num_chunk_list = 0; - } -#endif - - png_info_init_3(&info_ptr, png_sizeof(png_info)); -} #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ /* This function returns a pointer to the io_ptr associated with the user @@ -560,7 +637,7 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr) * pointer before png_write_destroy() or png_read_destroy() are called. */ png_voidp PNGAPI -png_get_io_ptr(png_structp png_ptr) +png_get_io_ptr(png_const_structrp png_ptr) { if (png_ptr == NULL) return (NULL); @@ -577,7 +654,7 @@ png_get_io_ptr(png_structp png_ptr) * function of your own because "FILE *" isn't necessarily available. */ void PNGAPI -png_init_io(png_structp png_ptr, png_FILE_p fp) +png_init_io(png_structrp png_ptr, png_FILE_p fp) { png_debug(1, "in png_init_io"); @@ -588,42 +665,52 @@ png_init_io(png_structp png_ptr, png_FILE_p fp) } # endif +#ifdef PNG_SAVE_INT_32_SUPPORTED +/* The png_save_int_32 function assumes integers are stored in two's + * complement format. If this isn't the case, then this routine needs to + * be modified to write data in two's complement format. Note that, + * the following works correctly even if png_int_32 has more than 32 bits + * (compare the more complex code required on read for sign extension.) + */ +void PNGAPI +png_save_int_32(png_bytep buf, png_int_32 i) +{ + buf[0] = (png_byte)((i >> 24) & 0xff); + buf[1] = (png_byte)((i >> 16) & 0xff); + buf[2] = (png_byte)((i >> 8) & 0xff); + buf[3] = (png_byte)(i & 0xff); +} +#endif + # ifdef PNG_TIME_RFC1123_SUPPORTED /* Convert the supplied time into an RFC 1123 string suitable for use in * a "Creation Time" or other text-based time string. */ -png_const_charp PNGAPI -png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime) +int PNGAPI +png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime) { static PNG_CONST char short_months[12][4] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; - if (png_ptr == NULL) - return (NULL); + if (out == NULL) + return 0; if (ptime->year > 9999 /* RFC1123 limitation */ || ptime->month == 0 || ptime->month > 12 || ptime->day == 0 || ptime->day > 31 || ptime->hour > 23 || ptime->minute > 59 || ptime->second > 60) - { - png_warning(png_ptr, "Ignoring invalid time value"); - return (NULL); - } + return 0; { size_t pos = 0; char number_buf[5]; /* enough for a four-digit year */ -# define APPEND_STRING(string)\ - pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\ - pos, (string)) +# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string)) # define APPEND_NUMBER(format, value)\ APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value))) -# define APPEND(ch)\ - if (pos < (sizeof png_ptr->time_buffer)-1)\ - png_ptr->time_buffer[pos++] = (ch) +# define APPEND(ch) if (pos < 28) out[pos++] = (ch) APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day); APPEND(' '); @@ -643,14 +730,37 @@ png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime) # undef APPEND_STRING } - return png_ptr->time_buffer; + return 1; } + +# if PNG_LIBPNG_VER < 10700 +/* To do: remove the following from libpng-1.7 */ +/* Original API that uses a private buffer in png_struct. + * Deprecated because it causes png_struct to carry a spurious temporary + * buffer (png_struct::time_buffer), better to have the caller pass this in. + */ +png_const_charp PNGAPI +png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime) +{ + if (png_ptr != NULL) + { + /* The only failure above if png_ptr != NULL is from an invalid ptime */ + if (!png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime)) + png_warning(png_ptr, "Ignoring invalid time value"); + + else + return png_ptr->time_buffer; + } + + return NULL; +} +# endif # endif /* PNG_TIME_RFC1123_SUPPORTED */ #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ png_const_charp PNGAPI -png_get_copyright(png_const_structp png_ptr) +png_get_copyright(png_const_structrp png_ptr) { PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ #ifdef PNG_STRING_COPYRIGHT @@ -658,13 +768,13 @@ png_get_copyright(png_const_structp png_ptr) #else # ifdef __STDC__ return PNG_STRING_NEWLINE \ - "libpng version 1.5.14 - January 24, 2013" PNG_STRING_NEWLINE \ + "libpng version 1.6.0 - February 14, 2013" PNG_STRING_NEWLINE \ "Copyright (c) 1998-2013 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ PNG_STRING_NEWLINE; # else - return "libpng version 1.5.14 - January 24, 2013\ + return "libpng version 1.6.0 - February 14, 2013\ Copyright (c) 1998-2013 Glenn Randers-Pehrson\ Copyright (c) 1996-1997 Andreas Dilger\ Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; @@ -681,14 +791,14 @@ png_get_copyright(png_const_structp png_ptr) * it is guaranteed that png.c uses the correct version of png.h. */ png_const_charp PNGAPI -png_get_libpng_ver(png_const_structp png_ptr) +png_get_libpng_ver(png_const_structrp png_ptr) { /* Version of *.c files used when building libpng */ return png_get_header_ver(png_ptr); } png_const_charp PNGAPI -png_get_header_ver(png_const_structp png_ptr) +png_get_header_ver(png_const_structrp png_ptr) { /* Version of *.h files used when building libpng */ PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ @@ -696,7 +806,7 @@ png_get_header_ver(png_const_structp png_ptr) } png_const_charp PNGAPI -png_get_header_version(png_const_structp png_ptr) +png_get_header_version(png_const_structrp png_ptr) { /* Returns longer string containing both version and date */ PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ @@ -711,52 +821,61 @@ png_get_header_version(png_const_structp png_ptr) #endif } -#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED int PNGAPI -png_handle_as_unknown(png_structp png_ptr, png_const_bytep chunk_name) +png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name) { /* Check chunk_name and return "keep" value if it's on the list, else 0 */ png_const_bytep p, p_end; - if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list <= 0) + if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0) return PNG_HANDLE_CHUNK_AS_DEFAULT; p_end = png_ptr->chunk_list; p = p_end + png_ptr->num_chunk_list*5; /* beyond end */ /* The code is the fifth byte after each four byte string. Historically this - * code was always searched from the end of the list, so it should continue - * to do so in case there are duplicated entries. + * code was always searched from the end of the list, this is no longer + * necessary because the 'set' routine handles duplicate entries correcty. */ do /* num_chunk_list > 0, so at least one */ { p -= 5; - if (!png_memcmp(chunk_name, p, 4)) + + if (!memcmp(chunk_name, p, 4)) return p[4]; } while (p > p_end); + /* This means that known chunks should be processed and unknown chunks should + * be handled according to the value of png_ptr->unknown_default; this can be + * confusing because, as a result, there are two levels of defaulting for + * unknown chunks. + */ return PNG_HANDLE_CHUNK_AS_DEFAULT; } +#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED int /* PRIVATE */ -png_chunk_unknown_handling(png_structp png_ptr, png_uint_32 chunk_name) +png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name) { png_byte chunk_string[5]; PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name); return png_handle_as_unknown(png_ptr, chunk_string); } -#endif +#endif /* READ_UNKNOWN_CHUNKS */ +#endif /* SET_UNKNOWN_CHUNKS */ #ifdef PNG_READ_SUPPORTED /* This function, added to libpng-1.0.6g, is untested. */ int PNGAPI -png_reset_zstream(png_structp png_ptr) +png_reset_zstream(png_structrp png_ptr) { if (png_ptr == NULL) return Z_STREAM_ERROR; + /* WARNING: this resets the window bits to the maximum! */ return (inflateReset(&png_ptr->zstream)); } #endif /* PNG_READ_SUPPORTED */ @@ -772,114 +891,271 @@ png_access_version_number(void) #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) +/* Ensure that png_ptr->zstream.msg holds some appropriate error message string. + * If it doesn't 'ret' is used to set it to something appropriate, even in cases + * like Z_OK or Z_STREAM_END where the error code is apparently a success code. + */ +void /* PRIVATE */ +png_zstream_error(png_structrp png_ptr, int ret) +{ + /* Translate 'ret' into an appropriate error string, priority is given to the + * one in zstream if set. This always returns a string, even in cases like + * Z_OK or Z_STREAM_END where the error code is a success code. + */ + if (png_ptr->zstream.msg == NULL) switch (ret) + { + default: + case Z_OK: + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code"); + break; + + case Z_STREAM_END: + /* Normal exit */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream"); + break; + + case Z_NEED_DICT: + /* This means the deflate stream did not have a dictionary; this + * indicates a bogus PNG. + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary"); + break; + + case Z_ERRNO: + /* gz APIs only: should not happen */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error"); + break; + + case Z_STREAM_ERROR: + /* internal libpng error */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib"); + break; + + case Z_DATA_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream"); + break; + + case Z_MEM_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory"); + break; + + case Z_BUF_ERROR: + /* End of input or output; not a problem if the caller is doing + * incremental read or write. + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated"); + break; + + case Z_VERSION_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version"); + break; + + case PNG_UNEXPECTED_ZLIB_RETURN: + /* Compile errors here mean that zlib now uses the value co-opted in + * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above + * and change pngpriv.h. Note that this message is "... return", + * whereas the default/Z_OK one is "... return code". + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return"); + break; + } +} + /* png_convert_size: a PNGAPI but no longer in png.h, so deleted * at libpng 1.5.5! */ /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ -# ifdef PNG_CHECK_cHRM_SUPPORTED - -int /* PRIVATE */ -png_check_cHRM_fixed(png_structp png_ptr, - png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x, - png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y, - png_fixed_point blue_x, png_fixed_point blue_y) +#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */ +static int +png_colorspace_check_gamma(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_fixed_point gAMA, int from) + /* This is called to check a new gamma value against an existing one. The + * routine returns false if the new gamma value should not be written. + * + * 'from' says where the new gamma value comes from: + * + * 0: the new gamma value is the libpng estimate for an ICC profile + * 1: the new gamma value comes from a gAMA chunk + * 2: the new gamma value comes from an sRGB chunk + */ { - int ret = 1; - unsigned long xy_hi,xy_lo,yx_hi,yx_lo; + png_fixed_point gtest; + + if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 && + (!png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) || + png_gamma_significant(gtest))) + { + /* Either this is an sRGB image, in which case the calculated gamma + * approximation should match, or this is an image with a profile and the + * value libpng calculates for the gamma of the profile does not match the + * value recorded in the file. The former, sRGB, case is an error, the + * latter is just a warning. + */ + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2) + { + png_chunk_report(png_ptr, "gamma value does not match sRGB", + PNG_CHUNK_ERROR); + /* Do not overwrite an sRGB value */ + return from == 2; + } - png_debug(1, "in function png_check_cHRM_fixed"); + else /* sRGB tag not involved */ + { + png_chunk_report(png_ptr, "gamma value does not match libpng estimate", + PNG_CHUNK_WARNING); + return from == 1; + } + } - if (png_ptr == NULL) - return 0; + return 1; +} - /* (x,y,z) values are first limited to 0..100000 (PNG_FP_1), the white - * y must also be greater than 0. To test for the upper limit calculate - * (PNG_FP_1-y) - x must be <= to this for z to be >= 0 (and the expression - * cannot overflow.) At this point we know x and y are >= 0 and (x+y) is - * <= PNG_FP_1. The previous test on PNG_MAX_UINT_31 is removed because it - * pointless (and it produces compiler warnings!) +void /* PRIVATE */ +png_colorspace_set_gamma(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_fixed_point gAMA) +{ + /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't + * occur. Since the fixed point representation is assymetrical it is + * possible for 1/gamma to overflow the limit of 21474 and this means the + * gamma value must be at least 5/100000 and hence at most 20000.0. For + * safety the limits here are a little narrower. The values are 0.00016 to + * 6250.0, which are truly ridiculous gamma values (and will produce + * displays that are all black or all white.) + * + * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk + * handling code, which only required the value to be >0. */ - if (white_x < 0 || white_y <= 0 || - red_x < 0 || red_y < 0 || - green_x < 0 || green_y < 0 || - blue_x < 0 || blue_y < 0) - { - png_warning(png_ptr, - "Ignoring attempt to set negative chromaticity value"); - ret = 0; - } - /* And (x+y) must be <= PNG_FP_1 (so z is >= 0) */ - if (white_x > PNG_FP_1 - white_y) - { - png_warning(png_ptr, "Invalid cHRM white point"); - ret = 0; - } + png_const_charp errmsg; + + if (gAMA < 16 || gAMA > 625000000) + errmsg = "gamma value out of range"; + +# ifdef PNG_READ_gAMA_SUPPORTED + /* Allow the application to set the gamma value more than once */ + else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && + (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0) + errmsg = "duplicate"; +# endif - if (red_x > PNG_FP_1 - red_y) + /* Do nothing if the colorspace is already invalid */ + else if (colorspace->flags & PNG_COLORSPACE_INVALID) + return; + + else { - png_warning(png_ptr, "Invalid cHRM red point"); - ret = 0; + if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, 1/*from gAMA*/)) + { + /* Store this gamma value. */ + colorspace->gamma = gAMA; + colorspace->flags |= + (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA); + } + + /* At present if the check_gamma test fails the gamma of the colorspace is + * not updated however the colorspace is not invalidated. This + * corresponds to the case where the existing gamma comes from an sRGB + * chunk or profile. An error message has already been output. + */ + return; } - if (green_x > PNG_FP_1 - green_y) + /* Error exit - errmsg has been set. */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR); +} + +void /* PRIVATE */ +png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr) +{ + if (info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) { - png_warning(png_ptr, "Invalid cHRM green point"); - ret = 0; + /* Everything is invalid */ + info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB| + PNG_INFO_iCCP); + +# ifdef PNG_COLORSPACE_SUPPORTED + /* Clean up the iCCP profile now if it won't be used. */ + png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/); +# else + PNG_UNUSED(png_ptr) +# endif } - if (blue_x > PNG_FP_1 - blue_y) + else { - png_warning(png_ptr, "Invalid cHRM blue point"); - ret = 0; - } +# ifdef PNG_COLORSPACE_SUPPORTED + /* Leave the INFO_iCCP flag set if the pngset.c code has already set + * it; this allows a PNG to contain a profile which matches sRGB and + * yet still have that profile retrievable by the application. + */ + if (info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) + info_ptr->valid |= PNG_INFO_sRGB; - png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo); - png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo); + else + info_ptr->valid &= ~PNG_INFO_sRGB; - if (xy_hi == yx_hi && xy_lo == yx_lo) - { - png_warning(png_ptr, - "Ignoring attempt to set cHRM RGB triangle with zero area"); - ret = 0; + if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) + info_ptr->valid |= PNG_INFO_cHRM; + + else + info_ptr->valid &= ~PNG_INFO_cHRM; +# endif + + if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) + info_ptr->valid |= PNG_INFO_gAMA; + + else + info_ptr->valid &= ~PNG_INFO_gAMA; } +} - return ret; +#ifdef PNG_READ_SUPPORTED +void /* PRIVATE */ +png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr) +{ + if (info_ptr == NULL) /* reduce code size; check here not in the caller */ + return; + + info_ptr->colorspace = png_ptr->colorspace; + png_colorspace_sync_info(png_ptr, info_ptr); } -# endif /* PNG_CHECK_cHRM_SUPPORTED */ +#endif +#endif -#ifdef PNG_cHRM_SUPPORTED +#ifdef PNG_COLORSPACE_SUPPORTED /* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for * cHRM, as opposed to using chromaticities. These internal APIs return * non-zero on a parameter error. The X, Y and Z values are required to be * positive and less than 1.0. */ -int png_xy_from_XYZ(png_xy *xy, png_XYZ XYZ) +static int +png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ) { png_int_32 d, dwhite, whiteX, whiteY; - d = XYZ.redX + XYZ.redY + XYZ.redZ; - if (!png_muldiv(&xy->redx, XYZ.redX, PNG_FP_1, d)) return 1; - if (!png_muldiv(&xy->redy, XYZ.redY, PNG_FP_1, d)) return 1; + d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z; + if (!png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d)) return 1; dwhite = d; - whiteX = XYZ.redX; - whiteY = XYZ.redY; + whiteX = XYZ->red_X; + whiteY = XYZ->red_Y; - d = XYZ.greenX + XYZ.greenY + XYZ.greenZ; - if (!png_muldiv(&xy->greenx, XYZ.greenX, PNG_FP_1, d)) return 1; - if (!png_muldiv(&xy->greeny, XYZ.greenY, PNG_FP_1, d)) return 1; + d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z; + if (!png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d)) return 1; dwhite += d; - whiteX += XYZ.greenX; - whiteY += XYZ.greenY; + whiteX += XYZ->green_X; + whiteY += XYZ->green_Y; - d = XYZ.blueX + XYZ.blueY + XYZ.blueZ; - if (!png_muldiv(&xy->bluex, XYZ.blueX, PNG_FP_1, d)) return 1; - if (!png_muldiv(&xy->bluey, XYZ.blueY, PNG_FP_1, d)) return 1; + d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z; + if (!png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d)) return 1; dwhite += d; - whiteX += XYZ.blueX; - whiteY += XYZ.blueY; + whiteX += XYZ->blue_X; + whiteY += XYZ->blue_Y; - /* The reference white is simply the same of the end-point (X,Y,Z) vectors, + /* The reference white is simply the sum of the end-point (X,Y,Z) vectors, * thus: */ if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1; @@ -888,7 +1164,8 @@ int png_xy_from_XYZ(png_xy *xy, png_XYZ XYZ) return 0; } -int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy) +static int +png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy) { png_fixed_point red_inverse, green_inverse, blue_scale; png_fixed_point left, right, denominator; @@ -897,14 +1174,14 @@ int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy) * have end points with 0 tristimulus values (these are impossible end * points, but they are used to cover the possible colors.) */ - if (xy.redx < 0 || xy.redx > PNG_FP_1) return 1; - if (xy.redy < 0 || xy.redy > PNG_FP_1-xy.redx) return 1; - if (xy.greenx < 0 || xy.greenx > PNG_FP_1) return 1; - if (xy.greeny < 0 || xy.greeny > PNG_FP_1-xy.greenx) return 1; - if (xy.bluex < 0 || xy.bluex > PNG_FP_1) return 1; - if (xy.bluey < 0 || xy.bluey > PNG_FP_1-xy.bluex) return 1; - if (xy.whitex < 0 || xy.whitex > PNG_FP_1) return 1; - if (xy.whitey < 0 || xy.whitey > PNG_FP_1-xy.whitex) return 1; + if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1; + if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1; + if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1; + if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1; + if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1; + if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1; + if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1; + if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1; /* The reverse calculation is more difficult because the original tristimulus * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8 @@ -1085,91 +1362,996 @@ int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy) /* By the argument, above overflow should be impossible here. The return * value of 2 indicates an internal error to the caller. */ - if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.redy - xy.bluey, 7)) return 2; - if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.redx - xy.bluex, 7)) return 2; + if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7)) + return 2; + if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7)) + return 2; denominator = left - right; /* Now find the red numerator. */ - if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2; - if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.whitex-xy.bluex, 7)) return 2; + if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7)) + return 2; + if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7)) + return 2; /* Overflow is possible here and it indicates an extreme set of PNG cHRM * chunk values. This calculation actually returns the reciprocal of the * scale value because this allows us to delay the multiplication of white-y * into the denominator, which tends to produce a small number. */ - if (!png_muldiv(&red_inverse, xy.whitey, denominator, left-right) || - red_inverse <= xy.whitey /* r+g+b scales = white scale */) + if (!png_muldiv(&red_inverse, xy->whitey, denominator, left-right) || + red_inverse <= xy->whitey /* r+g+b scales = white scale */) return 1; /* Similarly for green_inverse: */ - if (!png_muldiv(&left, xy.redy-xy.bluey, xy.whitex-xy.bluex, 7)) return 2; - if (!png_muldiv(&right, xy.redx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2; - if (!png_muldiv(&green_inverse, xy.whitey, denominator, left-right) || - green_inverse <= xy.whitey) + if (!png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7)) + return 2; + if (!png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7)) + return 2; + if (!png_muldiv(&green_inverse, xy->whitey, denominator, left-right) || + green_inverse <= xy->whitey) return 1; /* And the blue scale, the checks above guarantee this can't overflow but it * can still produce 0 for extreme cHRM values. */ - blue_scale = png_reciprocal(xy.whitey) - png_reciprocal(red_inverse) - + blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) - png_reciprocal(green_inverse); if (blue_scale <= 0) return 1; /* And fill in the png_XYZ: */ - if (!png_muldiv(&XYZ->redX, xy.redx, PNG_FP_1, red_inverse)) return 1; - if (!png_muldiv(&XYZ->redY, xy.redy, PNG_FP_1, red_inverse)) return 1; - if (!png_muldiv(&XYZ->redZ, PNG_FP_1 - xy.redx - xy.redy, PNG_FP_1, + if (!png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse)) return 1; + if (!png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse)) return 1; + if (!png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1, red_inverse)) return 1; - if (!png_muldiv(&XYZ->greenX, xy.greenx, PNG_FP_1, green_inverse)) return 1; - if (!png_muldiv(&XYZ->greenY, xy.greeny, PNG_FP_1, green_inverse)) return 1; - if (!png_muldiv(&XYZ->greenZ, PNG_FP_1 - xy.greenx - xy.greeny, PNG_FP_1, + if (!png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse)) return 1; + if (!png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse)) return 1; + if (!png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1, green_inverse)) return 1; - if (!png_muldiv(&XYZ->blueX, xy.bluex, blue_scale, PNG_FP_1)) return 1; - if (!png_muldiv(&XYZ->blueY, xy.bluey, blue_scale, PNG_FP_1)) return 1; - if (!png_muldiv(&XYZ->blueZ, PNG_FP_1 - xy.bluex - xy.bluey, blue_scale, + if (!png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1)) return 1; + if (!png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1)) return 1; + if (!png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale, PNG_FP_1)) return 1; return 0; /*success*/ } -int png_XYZ_from_xy_checked(png_structp png_ptr, png_XYZ *XYZ, png_xy xy) +static int +png_XYZ_normalize(png_XYZ *XYZ) +{ + png_int_32 Y; + + if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 || + XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 || + XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0) + return 1; + + /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1. + * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore + * relying on addition of two positive values producing a negative one is not + * safe. + */ + Y = XYZ->red_Y; + if (0x7fffffff - Y < XYZ->green_X) return 1; + Y += XYZ->green_Y; + if (0x7fffffff - Y < XYZ->blue_X) return 1; + Y += XYZ->blue_Y; + + if (Y != PNG_FP_1) + { + if (!png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y)) return 1; + + if (!png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y)) return 1; + + if (!png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y)) return 1; + } + + return 0; +} + +static int +png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta) +{ + /* Allow an error of +/-0.01 (absolute value) on each chromaticity */ + return !(PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) || + PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) || + PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) || + PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) || + PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) || + PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) || + PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) || + PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta)); +} + +/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM + * chunk chromaticities. Earlier checks used to simply look for the overflow + * condition (where the determinant of the matrix to solve for XYZ ends up zero + * because the chromaticity values are not all distinct.) Despite this it is + * theoretically possible to produce chromaticities that are apparently valid + * but that rapidly degrade to invalid, potentially crashing, sets because of + * arithmetic inaccuracies when calculations are performed on them. The new + * check is to round-trip xy -> XYZ -> xy and then check that the result is + * within a small percentage of the original. + */ +static int +png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy) +{ + int result; + png_xy xy_test; + + /* As a side-effect this routine also returns the XYZ endpoints. */ + result = png_XYZ_from_xy(XYZ, xy); + if (result) return result; + + result = png_xy_from_XYZ(&xy_test, XYZ); + if (result) return result; + + if (png_colorspace_endpoints_match(xy, &xy_test, + 5/*actually, the math is pretty accurate*/)) + return 0; + + /* Too much slip */ + return 1; +} + +/* This is the check going the other way. The XYZ is modified to normalize it + * (another side-effect) and the xy chromaticities are returned. + */ +static int +png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ) +{ + int result; + png_XYZ XYZtemp; + + result = png_XYZ_normalize(XYZ); + if (result) return result; + + result = png_xy_from_XYZ(xy, XYZ); + if (result) return result; + + XYZtemp = *XYZ; + return png_colorspace_check_xy(&XYZtemp, xy); +} + +/* Used to check for an endpoint match against sRGB */ +static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */ { - switch (png_XYZ_from_xy(XYZ, xy)) + /* color x y */ + /* red */ 64000, 33000, + /* green */ 30000, 60000, + /* blue */ 15000, 6000, + /* white */ 31270, 32900 +}; + +static int +png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ, + int preferred) +{ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + /* The consistency check is performed on the chromaticities; this factors out + * variations because of the normalization (or not) of the end point Y + * values. + */ + if (preferred < 2 && (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + /* The end points must be reasonably close to any we already have. The + * following allows an error of up to +/-.001 + */ + if (!png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, 100)) + { + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "inconsistent chromaticities"); + return 0; /* failed */ + } + + /* Only overwrite with preferred values */ + if (!preferred) + return 1; /* ok, but no change */ + } + + colorspace->end_points_xy = *xy; + colorspace->end_points_XYZ = *XYZ; + colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS; + + /* The end points are normally quoted to two decimal digits, so allow +/-0.01 + * on this test. + */ + if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000)) + colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB; + + else + colorspace->flags &= PNG_COLORSPACE_CANCEL( + PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); + + return 2; /* ok and changed */ +} + +int /* PRIVATE */ +png_colorspace_set_chromaticities(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_xy *xy, int preferred) +{ + /* We must check the end points to ensure they are reasonable - in the past + * color management systems have crashed as a result of getting bogus + * colorant values, while this isn't the fault of libpng it is the + * responsibility of libpng because PNG carries the bomb and libpng is in a + * position to protect against it. + */ + png_XYZ XYZ; + + switch (png_colorspace_check_xy(&XYZ, xy)) { case 0: /* success */ - return 1; + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ, + preferred); case 1: - /* The chunk may be technically valid, but we got png_fixed_point - * overflow while trying to get XYZ values out of it. This is - * entirely benign - the cHRM chunk is pretty extreme. + /* We can't invert the chromaticities so we can't produce value XYZ + * values. Likely as not a color management system will fail too. */ - png_warning(png_ptr, - "extreme cHRM chunk cannot be converted to tristimulus values"); + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "invalid chromaticities"); break; default: /* libpng is broken; this should be a warning but if it happens we * want error reports so for the moment it is an error. */ - png_error(png_ptr, "internal error in png_XYZ_from_xy"); + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_error(png_ptr, "internal error checking chromaticities"); + break; + } + + return 0; /* failed */ +} + +int /* PRIVATE */ +png_colorspace_set_endpoints(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred) +{ + png_XYZ XYZ = *XYZ_in; + png_xy xy; + + switch (png_colorspace_check_XYZ(&xy, &XYZ)) + { + case 0: + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ, + preferred); + + case 1: + /* End points are invalid. */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "invalid end points"); + break; + + default: + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_error(png_ptr, "internal error checking chromaticities"); + break; + } + + return 0; /* failed */ +} + +#if defined PNG_sRGB_SUPPORTED || defined PNG_iCCP_SUPPORTED +/* Error message generation */ +static char +png_icc_tag_char(png_uint_32 byte) +{ + byte &= 0xff; + if (byte >= 32 && byte <= 126) + return (char)byte; + else + return '?'; +} + +static void +png_icc_tag_name(char *name, png_uint_32 tag) +{ + name[0] = '\''; + name[1] = png_icc_tag_char(tag >> 24); + name[2] = png_icc_tag_char(tag >> 16); + name[3] = png_icc_tag_char(tag >> 8); + name[4] = png_icc_tag_char(tag ); + name[5] = '\''; +} + +static int +is_ICC_signature_char(png_alloc_size_t it) +{ + return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) || + (it >= 97 && it <= 122); +} + +static int is_ICC_signature(png_alloc_size_t it) +{ + return is_ICC_signature_char(it >> 24) /* checks all the top bits */ && + is_ICC_signature_char((it >> 16) & 0xff) && + is_ICC_signature_char((it >> 8) & 0xff) && + is_ICC_signature_char(it & 0xff); +} + +static int +png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_alloc_size_t value, png_const_charp reason) +{ + size_t pos; + char message[196]; /* see below for calculation */ + + if (colorspace != NULL) + colorspace->flags |= PNG_COLORSPACE_INVALID; + + pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */ + pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */ + pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */ + if (is_ICC_signature(value)) + { + /* So 'value' is at most 4 bytes and the following cast is safe */ + png_icc_tag_name(message+pos, (png_uint_32)value); + pos += 6; /* total +8; less than the else clause */ + message[pos++] = ':'; + message[pos++] = ' '; + } +# ifdef PNG_WARNINGS_SUPPORTED + else + { + char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/ + + pos = png_safecat(message, (sizeof message), pos, + png_format_number(number, number+(sizeof number), + PNG_NUMBER_FORMAT_x, value)); + pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/ + } +# endif + /* The 'reason' is an arbitrary message, allow +79 maximum 195 */ + pos = png_safecat(message, (sizeof message), pos, reason); + + /* This is recoverable, but make it unconditionally an app_error on write to + * avoid writing invalid ICC profiles into PNG files. (I.e. we handle them + * on read, with a warning, but on write unless the app turns off + * application errors the PNG won't be written.) + */ + png_chunk_report(png_ptr, message, + (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR); + + return 0; +} +#endif /* sRGB || iCCP */ + +#ifdef PNG_sRGB_SUPPORTED +int /* PRIVATE */ +png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace, + int intent) +{ + /* sRGB sets known gamma, end points and (from the chunk) intent. */ + /* IMPORTANT: these are not necessarily the values found in an ICC profile + * because ICC profiles store values adapted to a D50 environment; it is + * expected that the ICC profile mediaWhitePointTag will be D50, see the + * checks and code elsewhere to understand this better. + * + * These XYZ values, which are accurate to 5dp, produce rgb to gray + * coefficients of (6968,23435,2366), which are reduced (because they add up + * to 32769 not 32768) to (6968,23434,2366). These are the values that + * libpng has traditionally used (and are the best values given the 15bit + * algorithm used by the rgb to gray code.) + */ + static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */ + { + /* color X Y Z */ + /* red */ 41239, 21264, 1933, + /* green */ 35758, 71517, 11919, + /* blue */ 18048, 7219, 95053 + }; + + /* Do nothing if the colorspace is already invalidated. */ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + /* Check the intent, then check for existing settings. It is valid for the + * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must + * be consistent with the correct values. If, however, this function is + * called below because an iCCP chunk matches sRGB then it is quite + * conceivable that an older app recorded incorrect gAMA and cHRM because of + * an incorrect calculation based on the values in the profile - this does + * *not* invalidate the profile (though it still produces an error, which can + * be ignored.) + */ + if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST) + return png_icc_profile_error(png_ptr, colorspace, "sRGB", + (unsigned)intent, "invalid sRGB rendering intent"); + + if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 && + colorspace->rendering_intent != intent) + return png_icc_profile_error(png_ptr, colorspace, "sRGB", + (unsigned)intent, "inconsistent rendering intents"); + + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0) + { + png_benign_error(png_ptr, "duplicate sRGB information ignored"); + return 0; + } + + /* If the standard sRGB cHRM chunk does not match the one from the PNG file + * warn but overwrite the value with the correct one. + */ + if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 && + !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy, + 100)) + png_chunk_report(png_ptr, "cHRM chunk does not match sRGB", + PNG_CHUNK_ERROR); + + /* This check is just done for the error reporting - the routine always + * returns true when the 'from' argument corresponds to sRGB (2). + */ + (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE, + 2/*from sRGB*/); + + /* intent: bugs in GCC force 'int' to be used as the parameter type. */ + colorspace->rendering_intent = (png_uint_16)intent; + colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT; + + /* endpoints */ + colorspace->end_points_xy = sRGB_xy; + colorspace->end_points_XYZ = sRGB_XYZ; + colorspace->flags |= + (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); + + /* gamma */ + colorspace->gamma = PNG_GAMMA_sRGB_INVERSE; + colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA; + + /* Finally record that we have an sRGB profile */ + colorspace->flags |= + (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB); + + return 1; /* set */ +} +#endif /* sRGB */ + +#ifdef PNG_iCCP_SUPPORTED +/* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value + * is XYZ(0.9642,1.0,0.8249), which scales to: + * + * (63189.8112, 65536, 54060.6464) + */ +static const png_byte D50_nCIEXYZ[12] = + { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d }; + +int /* PRIVATE */ +png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length) +{ + if (profile_length < 132) + return png_icc_profile_error(png_ptr, colorspace, name, profile_length, + "too short"); + + if (profile_length & 3) + return png_icc_profile_error(png_ptr, colorspace, name, profile_length, + "invalid length"); + + return 1; +} + +int /* PRIVATE */ +png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, + png_const_bytep profile/* first 132 bytes only */, int color_type) +{ + png_uint_32 temp; + + /* Length check; this cannot be ignored in this code because profile_length + * is used later to check the tag table, so even if the profile seems over + * long profile_length from the caller must be correct. The caller can fix + * this up on read or write by just passing in the profile header length. + */ + temp = png_get_uint_32(profile); + if (temp != profile_length) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "length does not match profile"); + + temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */ + if (temp > 357913930 || /* (2^32-4-132)/12: maxium possible tag count */ + profile_length < 132+12*temp) /* truncated tag table */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "tag count too large"); + + /* The 'intent' must be valid or we can't store it, ICC limits the intent to + * 16 bits. + */ + temp = png_get_uint_32(profile+64); + if (temp >= 0xffff) /* The ICC limit */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid rendering intent"); + + /* This is just a warning because the profile may be valid in future + * versions. + */ + if (temp >= PNG_sRGB_INTENT_LAST) + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "intent outside defined range"); + + /* At this point the tag table can't be checked because it hasn't necessarily + * been loaded; however, various header fields can be checked. These checks + * are for values permitted by the PNG spec in an ICC profile; the PNG spec + * restricts the profiles that can be passed in an iCCP chunk (they must be + * appropriate to processing PNG data!) + */ + + /* Data checks (could be skipped). These checks must be independent of the + * version number; however, the version number doesn't accomodate changes in + * the header fields (just the known tags and the interpretation of the + * data.) + */ + temp = png_get_uint_32(profile+36); /* signature 'ascp' */ + if (temp != 0x61637370) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid signature"); + + /* Currently the PCS illuminant/adopted white point (the computational + * white point) are required to be D50, + * however the profile contains a record of the illuminant so perhaps ICC + * expects to be able to change this in the future (despite the rationale in + * the introduction for using a fixed PCS adopted white.) Consequently the + * following is just a warning. + */ + if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0) + (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/, + "PCS illuminant is not D50"); + + /* The PNG spec requires this: + * "If the iCCP chunk is present, the image samples conform to the colour + * space represented by the embedded ICC profile as defined by the + * International Color Consortium [ICC]. The colour space of the ICC profile + * shall be an RGB colour space for colour images (PNG colour types 2, 3, and + * 6), or a greyscale colour space for greyscale images (PNG colour types 0 + * and 4)." + * + * This checking code ensures the embedded profile (on either read or write) + * conforms to the specification requirements. Notice that an ICC 'gray' + * color-space profile contains the information to transform the monochrome + * data to XYZ or L*a*b (according to which PCS the profile uses) and this + * should be used in preference to the standard libpng K channel replication + * into R, G and B channels. + * + * Previously it was suggested that an RGB profile on grayscale data could be + * handled. However it it is clear that using an RGB profile in this context + * must be an error - there is no specification of what it means. Thus it is + * almost certainly more correct to ignore the profile. + */ + temp = png_get_uint_32(profile+16); /* data colour space field */ + switch (temp) + { + case 0x52474220: /* 'RGB ' */ + if (!(color_type & PNG_COLOR_MASK_COLOR)) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "RGB color space not permitted on grayscale PNG"); + break; + + case 0x47524159: /* 'GRAY' */ + if (color_type & PNG_COLOR_MASK_COLOR) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "Gray color space not permitted on RGB PNG"); + break; + + default: + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid ICC profile color space"); + } + + /* It is up to the application to check that the profile class matches the + * application requirements; the spec provides no guidance, but it's pretty + * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer + * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these + * cases. Issue an error for device link or abstract profiles - these don't + * contain the records necessary to transform the color-space to anything + * other than the target device (and not even that for an abstract profile). + * Profiles of these classes may not be embedded in images. + */ + temp = png_get_uint_32(profile+12); /* profile/device class */ + switch (temp) + { + case 0x73636E72: /* 'scnr' */ + case 0x6D6E7472: /* 'mntr' */ + case 0x70727472: /* 'prtr' */ + case 0x73706163: /* 'spac' */ + /* All supported */ + break; + + case 0x61627374: /* 'abst' */ + /* May not be embedded in an image */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid embedded Abstract ICC profile"); + + case 0x6C696E6B: /* 'link' */ + /* DeviceLink profiles cannnot be interpreted in a non-device specific + * fashion, if an app uses the AToB0Tag in the profile the results are + * undefined unless the result is sent to the intended device, + * therefore a DeviceLink profile should not be found embedded in a + * PNG. + */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "unexpected DeviceLink ICC profile class"); + + case 0x6E6D636C: /* 'nmcl' */ + /* A NamedColor profile is also device specific, however it doesn't + * contain an AToB0 tag that is open to misintrepretation. Almost + * certainly it will fail the tests below. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "unexpected NamedColor ICC profile class"); + break; + + default: + /* To allow for future enhancements to the profile accept unrecognized + * profile classes with a warning, these then hit the test below on the + * tag content to ensure they are backward compatible with one of the + * understood profiles. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "unrecognized ICC profile class"); break; } - /* ERROR RETURN */ + /* For any profile other than a device link one the PCS must be encoded + * either in XYZ or Lab. + */ + temp = png_get_uint_32(profile+20); + switch (temp) + { + case 0x58595A20: /* 'XYZ ' */ + case 0x4C616220: /* 'Lab ' */ + break; + + default: + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "unexpected ICC PCS encoding"); + } + + return 1; +} + +int /* PRIVATE */ +png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, + png_const_bytep profile /* header plus whole tag table */) +{ + png_uint_32 tag_count = png_get_uint_32(profile+128); + png_uint_32 itag; + png_const_bytep tag = profile+132; /* The first tag */ + + /* First scan all the tags in the table and add bits to the icc_info value + * (temporarily in 'tags'). + */ + for (itag=0; itag < tag_count; ++itag, tag += 12) + { + png_uint_32 tag_id = png_get_uint_32(tag+0); + png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */ + png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */ + + /* The ICC specification does not exclude zero length tags, therefore the + * start might actually be anywhere if there is no data, but this would be + * a clear abuse of the intent of the standard so the start is checked for + * being in range. All defined tag types have an 8 byte header - a 4 byte + * type signature then 0. + */ + if ((tag_start & 3) != 0) + { + /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is + * only a warning here because libpng does not care about the + * alignment. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, tag_id, + "ICC profile tag start not a multiple of 4"); + } + + /* This is a hard error; potentially it can cause read outside the + * profile. + */ + if (tag_start > profile_length || tag_length > profile_length - tag_start) + return png_icc_profile_error(png_ptr, colorspace, name, tag_id, + "ICC profile tag outside profile"); + } + + return 1; /* success, maybe with warnings */ +} + +#ifdef PNG_sRGB_SUPPORTED +/* Information about the known ICC sRGB profiles */ +static const struct +{ + png_uint_32 adler, crc, length; + png_uint_32 md5[4]; + png_byte have_md5; + png_byte is_broken; + png_uint_16 intent; + +# define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0) +# define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\ + { adler, crc, length, md5, broke, intent }, + +} png_sRGB_checks[] = +{ + /* This data comes from contrib/tools/checksum-icc run on downloads of + * all four ICC sRGB profiles from www.color.org. + */ + /* adler32, crc32, MD5[4], intent, date, length, file-name */ + PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9, + PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0, + "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc") + + /* ICC sRGB v2 perceptual no black-compensation: */ + PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21, + PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0, + "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc") + + PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae, + PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0, + "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc") + + /* ICC sRGB v4 perceptual */ + PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812, + PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0, + "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc") + + /* The following profiles have no known MD5 checksum. If there is a match + * on the (empty) MD5 the other fields are used to attempt a match and + * a warning is produced. The first two of these profiles have a 'cprt' tag + * which suggests that they were also made by Hewlett Packard. + */ + PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0, + "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc") + + /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not + * match the D50 PCS illuminant in the header (it is in fact the D65 values, + * so the white point is recorded as the un-adapted value.) The profiles + * below only differ in one byte - the intent - and are basically the same as + * the previous profile except for the mediaWhitePointTag error and a missing + * chromaticAdaptationTag. + */ + PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/, + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual") + + PNG_ICC_CHECKSUM(0x0398f3fcUL, 0xf29e526dUL, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/, + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative") +}; + +static int +png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr, + png_const_bytep profile, uLong adler) +{ + /* The quick check is to verify just the MD5 signature and trust the + * rest of the data. Because the profile has already been verified for + * correctness this is safe. png_colorspace_set_sRGB will check the 'intent' + * field too, so if the profile has been edited with an intent not defined + * by sRGB (but maybe defined by a later ICC specification) the read of + * the profile will fail at that point. + */ + png_uint_32 length = 0; + png_uint_32 intent = 0x10000; /* invalid */ +#if PNG_sRGB_PROFILE_CHECKS > 1 + uLong crc = 0; /* the value for 0 length data */ +#endif + unsigned int i; + + for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i) + { + if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] && + png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] && + png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] && + png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3]) + { + /* This may be one of the old HP profiles without an MD5, in that + * case we can only use the length and Adler32 (note that these + * are not used by default if there is an MD5!) + */ +# if PNG_sRGB_PROFILE_CHECKS == 0 + if (png_sRGB_checks[i].have_md5) + return 1+png_sRGB_checks[i].is_broken; +# endif + + /* Profile is unsigned or more checks have been configured in. */ + if (length == 0) + { + length = png_get_uint_32(profile); + intent = png_get_uint_32(profile+64); + } + + /* Length *and* intent must match */ + if (length == png_sRGB_checks[i].length && + intent == png_sRGB_checks[i].intent) + { + /* Now calculate the alder32 if not done already. */ + if (adler == 0) + { + adler = adler32(0, NULL, 0); + adler = adler32(adler, profile, length); + } + + if (adler == png_sRGB_checks[i].adler) + { + /* These basic checks suggest that the data has not been + * modified, but if the check level is more than 1 perform + * our own crc32 checksum on the data. + */ +# if PNG_sRGB_PROFILE_CHECKS > 1 + if (crc == 0) + { + crc = crc32(0, NULL, 0); + crc = crc32(crc, profile, length); + } + + /* So this check must pass for the 'return' below to happen. + */ + if (crc == png_sRGB_checks[i].crc) +# endif + { + if (png_sRGB_checks[i].is_broken) + { + /* These profiles are known to have bad data that may cause + * problems if they are used, therefore attempt to + * discourage their use, skip the 'have_md5' warning below, + * which is made irrelevant by this error. + */ + png_chunk_report(png_ptr, "known incorrect sRGB profile", + PNG_CHUNK_ERROR); + } + + /* Warn that this being done; this isn't even an error since + * the profile is perfectly valid, but it would be nice if + * people used the up-to-date ones. + */ + else if (!png_sRGB_checks[i].have_md5) + { + png_chunk_report(png_ptr, + "out-of-date sRGB profile with no signature", + PNG_CHUNK_WARNING); + } + + return 1+png_sRGB_checks[i].is_broken; + } + } + } + +# if PNG_sRGB_PROFILE_CHECKS > 0 + /* The signature matched, but the profile had been changed in some + * way. This is an apparent violation of the ICC terms of use and, + * anyway, probably indicates a data error or uninformed hacking. + */ + if (png_sRGB_checks[i].have_md5) + png_benign_error(png_ptr, + "copyright violation: edited ICC profile ignored"); +# endif + } + } + + return 0; /* no match */ +} +#endif + +#ifdef PNG_sRGB_SUPPORTED +void /* PRIVATE */ +png_icc_set_sRGB(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_bytep profile, uLong adler) +{ + /* Is this profile one of the known ICC sRGB profiles? If it is, just set + * the sRGB information. + */ + if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler)) + (void)png_colorspace_set_sRGB(png_ptr, colorspace, + (int)/*already checked*/png_get_uint_32(profile+64)); +} +#endif /* PNG_READ_sRGB_SUPPORTED */ + +int /* PRIVATE */ +png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, png_const_bytep profile, + int color_type) +{ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + if (png_icc_check_length(png_ptr, colorspace, name, profile_length) && + png_icc_check_header(png_ptr, colorspace, name, profile_length, profile, + color_type) && + png_icc_check_tag_table(png_ptr, colorspace, name, profile_length, + profile)) + { + png_icc_set_sRGB(png_ptr, colorspace, profile, 0); + return 1; + } + + /* Failure case */ return 0; } +#endif /* iCCP */ + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +void /* PRIVATE */ +png_colorspace_set_rgb_coefficients(png_structrp png_ptr) +{ + /* Set the rgb_to_gray coefficients from the colorspace. */ + if (!png_ptr->rgb_to_gray_coefficients_set && + (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) + { + /* png_set_background has not been called, get the coefficients from the Y + * values of the colorspace colorants. + */ + png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y; + png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y; + png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y; + png_fixed_point total = r+g+b; + + if (total > 0 && + r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 && + g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 && + b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 && + r+g+b <= 32769) + { + /* We allow 0 coefficients here. r+g+b may be 32769 if two or + * all of the coefficients were rounded up. Handle this by + * reducing the *largest* coefficient by 1; this matches the + * approach used for the default coefficients in pngrtran.c + */ + int add = 0; + + if (r+g+b > 32768) + add = -1; + else if (r+g+b < 32768) + add = 1; + + if (add != 0) + { + if (g >= r && g >= b) + g += add; + else if (r >= g && r >= b) + r += add; + else + b += add; + } + + /* Check for an internal error. */ + if (r+g+b != 32768) + png_error(png_ptr, + "internal error handling cHRM coefficients"); + + else + { + png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r; + png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g; + } + } + + /* This is a png_error at present even though it could be ignored - + * it should never happen, but it is important that if it does, the + * bug is fixed. + */ + else + png_error(png_ptr, "internal error handling cHRM->XYZ"); + } +} #endif +#endif /* COLORSPACE */ + void /* PRIVATE */ -png_check_IHDR(png_structp png_ptr, +png_check_IHDR(png_const_structrp png_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, int interlace_type, int compression_type, int filter_type) @@ -1470,7 +2652,7 @@ static double png_pow10(int power) { int recip = 0; - double d = 1.0; + double d = 1; /* Handle negative exponent with a reciprocal at the end because * 10 is exact whereas .1 is inexact in base 2 @@ -1484,7 +2666,7 @@ png_pow10(int power) if (power > 0) { /* Decompose power bitwise. */ - double mult = 10.0; + double mult = 10; do { if (power & 1) d *= mult; @@ -1504,7 +2686,7 @@ png_pow10(int power) * precision. */ void /* PRIVATE */ -png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, +png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size, double fp, unsigned int precision) { /* We use standard functions from math.h, but not printf because @@ -1603,8 +2785,7 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, { double d; - fp *= 10.0; - + fp *= 10; /* Use modf here, not floor and subtract, so that * the separation is done in one step. At the end * of the loop don't break the number into parts so @@ -1617,7 +2798,7 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, { d = floor(fp + .5); - if (d > 9.0) + if (d > 9) { /* Rounding up to 10, handle that here. */ if (czero > 0) @@ -1625,10 +2806,9 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, --czero, d = 1; if (cdigits == 0) --clead; } - else { - while (cdigits > 0 && d > 9.0) + while (cdigits > 0 && d > 9) { int ch = *--ascii; @@ -1653,7 +2833,7 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, * exponent but take into account the leading * decimal point. */ - if (d > 9.0) /* cdigits == 0 */ + if (d > 9) /* cdigits == 0 */ { if (exp_b10 == (-1)) { @@ -1674,19 +2854,18 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, ++exp_b10; /* In all cases we output a '1' */ - d = 1.0; + d = 1; } } } fp = 0; /* Guarantees termination below. */ } - if (d == 0.0) + if (d == 0) { ++czero; if (cdigits == 0) ++clead; } - else { /* Included embedded zeros in the digit count. */ @@ -1714,7 +2893,6 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, above */ --exp_b10; } - *ascii++ = (char)(48 + (int)d), ++cdigits; } } @@ -1822,8 +3000,8 @@ png_ascii_from_fp(png_structp png_ptr, png_charp ascii, png_size_t size, /* Function to format a fixed point value in ASCII. */ void /* PRIVATE */ -png_ascii_from_fixed(png_structp png_ptr, png_charp ascii, png_size_t size, - png_fixed_point fp) +png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii, + png_size_t size, png_fixed_point fp) { /* Require space for 10 decimal digits, a decimal point, a minus sign and a * trailing \0, 13 characters: @@ -1893,9 +3071,14 @@ png_ascii_from_fixed(png_structp png_ptr, png_charp ascii, png_size_t size, #endif /* READ_SCAL */ #if defined(PNG_FLOATING_POINT_SUPPORTED) && \ - !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) + !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \ + (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \ + defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \ + (defined(PNG_sCAL_SUPPORTED) && \ + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)) png_fixed_point -png_fixed(png_structp png_ptr, double fp, png_const_charp text) +png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text) { double r = floor(100000 * fp + .5); @@ -2034,7 +3217,7 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times, * result. */ png_fixed_point -png_muldiv_warn(png_structp png_ptr, png_fixed_point a, png_int_32 times, +png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times, png_int_32 divisor) { png_fixed_point result; @@ -2047,8 +3230,7 @@ png_muldiv_warn(png_structp png_ptr, png_fixed_point a, png_int_32 times, } #endif -#if (defined PNG_READ_GAMMA_SUPPORTED) || (defined PNG_cHRM_SUPPORTED) -/* more fixed point functions for gamma and cHRM (xy/XYZ) suport. */ +#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */ /* Calculate a reciprocal, return 0 on div-by-zero or overflow. */ png_fixed_point png_reciprocal(png_fixed_point a) @@ -2068,6 +3250,17 @@ png_reciprocal(png_fixed_point a) return 0; /* error/overflow */ } +/* This is the shared test on whether a gamma value is 'significant' - whether + * it is worth doing gamma correction. + */ +int /* PRIVATE */ +png_gamma_significant(png_fixed_point gamma_val) +{ + return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || + gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; +} +#endif + #ifdef PNG_READ_GAMMA_SUPPORTED /* A local convenience routine. */ static png_fixed_point @@ -2090,7 +3283,6 @@ png_product2(png_fixed_point a, png_fixed_point b) return 0; /* overflow */ } -#endif /* READ_GAMMA */ /* The inverse of the above. */ png_fixed_point @@ -2118,75 +3310,30 @@ png_reciprocal2(png_fixed_point a, png_fixed_point b) return 0; /* overflow */ } -#endif /* READ_GAMMA || cHRM */ - -#ifdef PNG_CHECK_cHRM_SUPPORTED -/* Added at libpng version 1.2.34 (Dec 8, 2008) and 1.4.0 (Jan 2, - * 2010: moved from pngset.c) */ -/* - * Multiply two 32-bit numbers, V1 and V2, using 32-bit - * arithmetic, to produce a 64-bit result in the HI/LO words. - * - * A B - * x C D - * ------ - * AD || BD - * AC || CB || 0 - * - * where A and B are the high and low 16-bit words of V1, - * C and D are the 16-bit words of V2, AD is the product of - * A and D, and X || Y is (X << 16) + Y. -*/ - -void /* PRIVATE */ -png_64bit_product (long v1, long v2, unsigned long *hi_product, - unsigned long *lo_product) -{ - int a, b, c, d; - long lo, hi, x, y; - - a = (v1 >> 16) & 0xffff; - b = v1 & 0xffff; - c = (v2 >> 16) & 0xffff; - d = v2 & 0xffff; - - lo = b * d; /* BD */ - x = a * d + c * b; /* AD + CB */ - y = ((lo >> 16) & 0xffff) + x; - - lo = (lo & 0xffff) | ((y & 0xffff) << 16); - hi = (y >> 16) & 0xffff; - - hi += a * c; /* AC */ - - *hi_product = (unsigned long)hi; - *lo_product = (unsigned long)lo; -} -#endif /* CHECK_cHRM */ +#endif /* READ_GAMMA */ #ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */ #ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED /* Fixed point gamma. * + * The code to calculate the tables used below can be found in the shell script + * contrib/tools/intgamma.sh + * * To calculate gamma this code implements fast log() and exp() calls using only * fixed point arithmetic. This code has sufficient precision for either 8-bit * or 16-bit sample values. * * The tables used here were calculated using simple 'bc' programs, but C double - * precision floating point arithmetic would work fine. The programs are given - * at the head of each table. + * precision floating point arithmetic would work fine. * * 8-bit log table * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to * 255, so it's the base 2 logarithm of a normalized 8-bit floating point * mantissa. The numbers are 32-bit fractions. */ -static png_uint_32 +static const png_uint_32 png_8bit_l2[128] = { -# ifdef PNG_DO_BC - for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; } -# else 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U, 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U, 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U, @@ -2209,7 +3356,6 @@ png_8bit_l2[128] = 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U, 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U, 24347096U, 0U -# endif #if 0 /* The following are the values for 16-bit tables - these work fine for the @@ -2232,18 +3378,18 @@ png_8bit_l2[128] = #endif }; -PNG_STATIC png_int_32 +static png_int_32 png_log8bit(unsigned int x) { unsigned int lg2 = 0; /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log, * because the log is actually negate that means adding 1. The final * returned value thus has the range 0 (for 255 input) to 7.994 (for 1 - * input), return 7.99998 for the overflow (log 0) case - so the result is + * input), return -1 for the overflow (log 0) case, - so the result is * always at most 19 bits. */ if ((x &= 0xff) == 0) - return 0xffffffff; + return -1; if ((x & 0xf0) == 0) lg2 = 4, x <<= 4; @@ -2288,14 +3434,14 @@ png_log8bit(unsigned int x) * Zero (257): 0 * End (258): 23499 */ -PNG_STATIC png_int_32 +static png_int_32 png_log16bit(png_uint_32 x) { unsigned int lg2 = 0; /* As above, but now the input has 16 bits. */ if ((x &= 0xffff) == 0) - return 0xffffffff; + return -1; if ((x & 0xff00) == 0) lg2 = 8, x <<= 8; @@ -2345,7 +3491,7 @@ png_log16bit(png_uint_32 x) * integer bits (the top 4) simply determine a shift. * * The worst case is the 16-bit distinction between 65535 and 65534, this - * requires perhaps spurious accuracy in the decoding of the logarithm to + * requires perhaps spurious accuracty in the decoding of the logarithm to * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance * of getting this accuracy in practice. * @@ -2353,21 +3499,17 @@ png_log16bit(png_uint_32 x) * frational part of the logarithm by using an accurate 32-bit value from the * top four fractional bits then multiplying in the remaining bits. */ -static png_uint_32 +static const png_uint_32 png_32bit_exp[16] = { -# ifdef PNG_DO_BC - for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; } -# else /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */ 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U, 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U, 2553802834U, 2445529972U, 2341847524U, 2242560872U -# endif }; /* Adjustment table; provided to explain the numbers in the code below. */ -#ifdef PNG_DO_BC +#if 0 for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"} 11 44937.64284865548751208448 10 45180.98734845585101160448 @@ -2383,7 +3525,7 @@ for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"} 0 45425.85339951654943850496 #endif -PNG_STATIC png_uint_32 +static png_uint_32 png_exp(png_fixed_point x) { if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */ @@ -2431,7 +3573,7 @@ png_exp(png_fixed_point x) return 0; } -PNG_STATIC png_byte +static png_byte png_exp8bit(png_fixed_point lg2) { /* Get a 32-bit value: */ @@ -2445,7 +3587,7 @@ png_exp8bit(png_fixed_point lg2) return (png_byte)((x + 0x7fffffU) >> 24); } -PNG_STATIC png_uint_16 +static png_uint_16 png_exp16bit(png_fixed_point lg2) { /* Get a 32-bit value: */ @@ -2509,7 +3651,7 @@ png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val) * 8-bit (as are the arguments.) */ png_uint_16 /* PRIVATE */ -png_gamma_correct(png_structp png_ptr, unsigned int value, +png_gamma_correct(png_structrp png_ptr, unsigned int value, png_fixed_point gamma_val) { if (png_ptr->bit_depth == 8) @@ -2519,18 +3661,8 @@ png_gamma_correct(png_structp png_ptr, unsigned int value, return png_gamma_16bit_correct(value, gamma_val); } -/* This is the shared test on whether a gamma value is 'significant' - whether - * it is worth doing gamma correction. - */ -int /* PRIVATE */ -png_gamma_significant(png_fixed_point gamma_val) -{ - return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || - gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; -} - /* Internal function to build a single 16-bit table - the table consists of - * 'num' 256-entry subtables, where 'num' is determined by 'shift' - the amount + * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount * to shift the input values right (or 16-number_of_signifiant_bits). * * The caller is responsible for ensuring that the table gets cleaned up on @@ -2538,7 +3670,7 @@ png_gamma_significant(png_fixed_point gamma_val) * should be somewhere that will be cleaned. */ static void -png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable, +png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable, PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) { /* Various values derived from 'shift': */ @@ -2548,12 +3680,12 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable, unsigned int i; png_uint_16pp table = *ptable = - (png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p)); + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); for (i = 0; i < num; i++) { png_uint_16p sub_table = table[i] = - (png_uint_16p)png_malloc(png_ptr, 256 * png_sizeof(png_uint_16)); + (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16))); /* The 'threshold' test is repeated here because it can arise for one of * the 16-bit tables even if the others don't hit it. @@ -2606,7 +3738,7 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable, * required. */ static void -png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, +png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable, PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) { PNG_CONST unsigned int num = 1U << (8U - shift); @@ -2615,15 +3747,15 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, png_uint_32 last; png_uint_16pp table = *ptable = - (png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p)); + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); - /* 'num' is the number of tables and also the number of low bits of the - * input 16-bit value used to select a table. Each table is itself indexed - * by the high 8 bits of the value. + /* 'num' is the number of tables and also the number of low bits of low + * bits of the input 16-bit value used to select a table. Each table is + * itself index by the high 8 bits of the value. */ for (i = 0; i < num; i++) table[i] = (png_uint_16p)png_malloc(png_ptr, - 256 * png_sizeof(png_uint_16)); + 256 * (sizeof (png_uint_16))); /* 'gamma_val' is set to the reciprocal of the value calculated above, so * pow(out,g) is an *input* value. 'last' is the last input value set. @@ -2670,10 +3802,10 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable, /* Build a single 8-bit table: same as the 16-bit case but much simpler (and * typically much faster). Note that libpng currently does no sBIT processing - * (apparently contrary to the spec) so a 256-entry table is always generated. + * (apparently contrary to the spec) so a 256 entry table is always generated. */ static void -png_build_8bit_table(png_structp png_ptr, png_bytepp ptable, +png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable, PNG_CONST png_fixed_point gamma_val) { unsigned int i; @@ -2690,7 +3822,7 @@ png_build_8bit_table(png_structp png_ptr, png_bytepp ptable, * tables. */ void /* PRIVATE */ -png_destroy_gamma_table(png_structp png_ptr) +png_destroy_gamma_table(png_structrp png_ptr) { png_free(png_ptr, png_ptr->gamma_table); png_ptr->gamma_table = NULL; @@ -2746,7 +3878,7 @@ png_destroy_gamma_table(png_structp png_ptr) * we don't need to allocate > 64K chunks for a full 16-bit table. */ void /* PRIVATE */ -png_build_gamma_table(png_structp png_ptr, int bit_depth) +png_build_gamma_table(png_structrp png_ptr, int bit_depth) { png_debug(1, "in png_build_gamma_table"); @@ -2765,7 +3897,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) if (bit_depth <= 8) { png_build_8bit_table(png_ptr, &png_ptr->gamma_table, - png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->gamma, + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, png_ptr->screen_gamma) : PNG_FP_1); #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ @@ -2774,11 +3906,11 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) { png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1, - png_reciprocal(png_ptr->gamma)); + png_reciprocal(png_ptr->colorspace.gamma)); png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1, png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : - png_ptr->gamma/* Probably doing rgb_to_gray */); + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); } #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ } @@ -2806,7 +3938,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) * Where 'iv' is the input color value and 'ov' is the output value - * pow(iv, gamma). * - * Thus the gamma table consists of up to 256 256-entry tables. The table + * Thus the gamma table consists of up to 256 256 entry tables. The table * is selected by the (8-gamma_shift) most significant of the low 8 bits of * the color value then indexed by the upper 8 bits: * @@ -2847,13 +3979,13 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) #endif png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift, - png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma, + png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma, png_ptr->screen_gamma) : PNG_FP_1); #ifdef PNG_16BIT_SUPPORTED else png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift, - png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->gamma, + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, png_ptr->screen_gamma) : PNG_FP_1); #endif @@ -2863,7 +3995,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) { png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift, - png_reciprocal(png_ptr->gamma)); + png_reciprocal(png_ptr->colorspace.gamma)); /* Notice that the '16 from 1' table should be full precision, however * the lookup on this table still uses gamma_shift, so it can't be. @@ -2871,10 +4003,270 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth) */ png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift, png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : - png_ptr->gamma/* Probably doing rgb_to_gray */); + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); } #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ } } #endif /* READ_GAMMA */ + +/* sRGB support */ +#if defined PNG_SIMPLIFIED_READ_SUPPORTED ||\ + defined PNG_SIMPLIFIED_WRITE_SUPPORTED +/* sRGB conversion tables; these are machine generated with the code in + * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the + * specification (see the article at http://en.wikipedia.org/wiki/SRGB) + * is used, not the gamma=1/2.2 approximation use elsewhere in libpng. + * The sRGB to linear table is exact (to the nearest 16 bit linear fraction). + * The inverse (linear to sRGB) table has accuracies as follows: + * + * For all possible (255*65535+1) input values: + * + * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact + * + * For the input values corresponding to the 65536 16-bit values: + * + * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact + * + * In all cases the inexact readings are off by one. + */ + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED +/* The convert-to-sRGB table is only currently required for read. */ +const png_uint_16 png_sRGB_table[256] = +{ + 0,20,40,60,80,99,119,139, + 159,179,199,219,241,264,288,313, + 340,367,396,427,458,491,526,562, + 599,637,677,718,761,805,851,898, + 947,997,1048,1101,1156,1212,1270,1330, + 1391,1453,1517,1583,1651,1720,1790,1863, + 1937,2013,2090,2170,2250,2333,2418,2504, + 2592,2681,2773,2866,2961,3058,3157,3258, + 3360,3464,3570,3678,3788,3900,4014,4129, + 4247,4366,4488,4611,4736,4864,4993,5124, + 5257,5392,5530,5669,5810,5953,6099,6246, + 6395,6547,6700,6856,7014,7174,7335,7500, + 7666,7834,8004,8177,8352,8528,8708,8889, + 9072,9258,9445,9635,9828,10022,10219,10417, + 10619,10822,11028,11235,11446,11658,11873,12090, + 12309,12530,12754,12980,13209,13440,13673,13909, + 14146,14387,14629,14874,15122,15371,15623,15878, + 16135,16394,16656,16920,17187,17456,17727,18001, + 18277,18556,18837,19121,19407,19696,19987,20281, + 20577,20876,21177,21481,21787,22096,22407,22721, + 23038,23357,23678,24002,24329,24658,24990,25325, + 25662,26001,26344,26688,27036,27386,27739,28094, + 28452,28813,29176,29542,29911,30282,30656,31033, + 31412,31794,32179,32567,32957,33350,33745,34143, + 34544,34948,35355,35764,36176,36591,37008,37429, + 37852,38278,38706,39138,39572,40009,40449,40891, + 41337,41785,42236,42690,43147,43606,44069,44534, + 45002,45473,45947,46423,46903,47385,47871,48359, + 48850,49344,49841,50341,50844,51349,51858,52369, + 52884,53401,53921,54445,54971,55500,56032,56567, + 57105,57646,58190,58737,59287,59840,60396,60955, + 61517,62082,62650,63221,63795,64372,64952,65535 +}; + +#endif /* simplified read only */ + +/* The base/delta tables are required for both read and write (but currently + * only the simplified versions.) + */ +const png_uint_16 png_sRGB_base[512] = +{ + 128,1782,3383,4644,5675,6564,7357,8074, + 8732,9346,9921,10463,10977,11466,11935,12384, + 12816,13233,13634,14024,14402,14769,15125,15473, + 15812,16142,16466,16781,17090,17393,17690,17981, + 18266,18546,18822,19093,19359,19621,19879,20133, + 20383,20630,20873,21113,21349,21583,21813,22041, + 22265,22487,22707,22923,23138,23350,23559,23767, + 23972,24175,24376,24575,24772,24967,25160,25352, + 25542,25730,25916,26101,26284,26465,26645,26823, + 27000,27176,27350,27523,27695,27865,28034,28201, + 28368,28533,28697,28860,29021,29182,29341,29500, + 29657,29813,29969,30123,30276,30429,30580,30730, + 30880,31028,31176,31323,31469,31614,31758,31902, + 32045,32186,32327,32468,32607,32746,32884,33021, + 33158,33294,33429,33564,33697,33831,33963,34095, + 34226,34357,34486,34616,34744,34873,35000,35127, + 35253,35379,35504,35629,35753,35876,35999,36122, + 36244,36365,36486,36606,36726,36845,36964,37083, + 37201,37318,37435,37551,37668,37783,37898,38013, + 38127,38241,38354,38467,38580,38692,38803,38915, + 39026,39136,39246,39356,39465,39574,39682,39790, + 39898,40005,40112,40219,40325,40431,40537,40642, + 40747,40851,40955,41059,41163,41266,41369,41471, + 41573,41675,41777,41878,41979,42079,42179,42279, + 42379,42478,42577,42676,42775,42873,42971,43068, + 43165,43262,43359,43456,43552,43648,43743,43839, + 43934,44028,44123,44217,44311,44405,44499,44592, + 44685,44778,44870,44962,45054,45146,45238,45329, + 45420,45511,45601,45692,45782,45872,45961,46051, + 46140,46229,46318,46406,46494,46583,46670,46758, + 46846,46933,47020,47107,47193,47280,47366,47452, + 47538,47623,47709,47794,47879,47964,48048,48133, + 48217,48301,48385,48468,48552,48635,48718,48801, + 48884,48966,49048,49131,49213,49294,49376,49458, + 49539,49620,49701,49782,49862,49943,50023,50103, + 50183,50263,50342,50422,50501,50580,50659,50738, + 50816,50895,50973,51051,51129,51207,51285,51362, + 51439,51517,51594,51671,51747,51824,51900,51977, + 52053,52129,52205,52280,52356,52432,52507,52582, + 52657,52732,52807,52881,52956,53030,53104,53178, + 53252,53326,53400,53473,53546,53620,53693,53766, + 53839,53911,53984,54056,54129,54201,54273,54345, + 54417,54489,54560,54632,54703,54774,54845,54916, + 54987,55058,55129,55199,55269,55340,55410,55480, + 55550,55620,55689,55759,55828,55898,55967,56036, + 56105,56174,56243,56311,56380,56448,56517,56585, + 56653,56721,56789,56857,56924,56992,57059,57127, + 57194,57261,57328,57395,57462,57529,57595,57662, + 57728,57795,57861,57927,57993,58059,58125,58191, + 58256,58322,58387,58453,58518,58583,58648,58713, + 58778,58843,58908,58972,59037,59101,59165,59230, + 59294,59358,59422,59486,59549,59613,59677,59740, + 59804,59867,59930,59993,60056,60119,60182,60245, + 60308,60370,60433,60495,60558,60620,60682,60744, + 60806,60868,60930,60992,61054,61115,61177,61238, + 61300,61361,61422,61483,61544,61605,61666,61727, + 61788,61848,61909,61969,62030,62090,62150,62211, + 62271,62331,62391,62450,62510,62570,62630,62689, + 62749,62808,62867,62927,62986,63045,63104,63163, + 63222,63281,63340,63398,63457,63515,63574,63632, + 63691,63749,63807,63865,63923,63981,64039,64097, + 64155,64212,64270,64328,64385,64443,64500,64557, + 64614,64672,64729,64786,64843,64900,64956,65013, + 65070,65126,65183,65239,65296,65352,65409,65465 +}; + +const png_byte png_sRGB_delta[512] = +{ + 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54, + 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36, + 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28, + 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24, + 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21, + 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19, + 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17, + 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16, + 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15, + 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14, + 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13, + 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12, + 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12, + 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11, + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, + 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 +}; +#endif /* SIMPLIFIED READ/WRITE sRGB support */ + +/* SIMPLIFIED READ/WRITE SUPPORT */ +#if defined PNG_SIMPLIFIED_READ_SUPPORTED ||\ + defined PNG_SIMPLIFIED_WRITE_SUPPORTED +static int +png_image_free_function(png_voidp argument) +{ + png_imagep image = png_voidcast(png_imagep, argument); + png_controlp cp = image->opaque; + png_control c; + + /* Double check that we have a png_ptr - it should be impossible to get here + * without one. + */ + if (cp->png_ptr == NULL) + return 0; + + /* First free any data held in the control structure. */ +# ifdef PNG_STDIO_SUPPORTED + if (cp->owned_file) + { + FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr); + cp->owned_file = 0; + + /* Ignore errors here. */ + if (fp != NULL) + { + cp->png_ptr->io_ptr = NULL; + (void)fclose(fp); + } + } +# endif + + /* Copy the control structure so that the original, allocated, version can be + * safely freed. Notice that a png_error here stops the remainder of the + * cleanup, but this is probably fine because that would indicate bad memory + * problems anyway. + */ + c = *cp; + image->opaque = &c; + png_free(c.png_ptr, cp); + + /* Then the structures, calling the correct API. */ + if (c.for_write) + { +# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED + png_destroy_write_struct(&c.png_ptr, &c.info_ptr); +# else + png_error(c.png_ptr, "simplified write not supported"); +# endif + } + else + { +# ifdef PNG_SIMPLIFIED_READ_SUPPORTED + png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL); +# else + png_error(c.png_ptr, "simplified read not supported"); +# endif + } + + /* Success. */ + return 1; +} + +void PNGAPI +png_image_free(png_imagep image) +{ + /* Safely call the real function, but only if doing so is safe at this point + * (if not inside an error handling context). Otherwise assume + * png_safe_execute will call this API after the return. + */ + if (image != NULL && image->opaque != NULL && + image->opaque->error_buf == NULL) + { + /* Ignore errors here: */ + (void)png_safe_execute(image, png_image_free_function, image); + image->opaque = NULL; + } +} + +int /* PRIVATE */ +png_image_error(png_imagep image, png_const_charp error_message) +{ + /* Utility to log an error. */ + png_safecat(image->message, (sizeof image->message), 0, error_message); + image->warning_or_error |= PNG_IMAGE_ERROR; + png_image_free(image); + return 0; +} + +#endif /* SIMPLIFIED READ/WRITE */ #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ |