/* png.c - location for general purpose libpng functions * * Last changed in libpng 1.4.1 [February 25, 2010] * Copyright (c) 1998-2010 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.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h */ #define PNG_NO_EXTERN #define PNG_NO_PEDANTIC_WARNINGS #include "png.h" #include "pngpriv.h" /* Generate a compiler error if there is an old png.h in the search path. */ typedef version_1_4_2rc03 Your_png_h_is_not_version_1_4_2rc03; /* Version information for C files. This had better match the version * string defined in png.h. */ /* 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 * stream we can set num_bytes = 8 so that libpng will not attempt to read * or write any of the magic bytes before it starts on the IHDR. */ #ifdef PNG_READ_SUPPORTED void PNGAPI png_set_sig_bytes(png_structp png_ptr, int num_bytes) { png_debug(1, "in png_set_sig_bytes"); if (png_ptr == NULL) return; if (num_bytes > 8) png_error(png_ptr, "Too many bytes for PNG signature"); png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes); } /* Checks whether the supplied bytes match the PNG signature. We allow * checking less than the full 8-byte signature so that those apps that * already read the first few bytes of a file to determine the file type * can simply check the remaining bytes for extra assurance. Returns * an integer less than, equal to, or greater than zero if sig is found, * respectively, to be less than, to match, or be greater than the correct * PNG signature (this is the same behaviour as strcmp, memcmp, etc). */ int PNGAPI png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check) { png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; if (num_to_check > 8) num_to_check = 8; else if (num_to_check < 1) return (-1); if (start > 7) return (-1); if (start + num_to_check > 8) num_to_check = 8 - start; return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check))); } #endif /* PNG_READ_SUPPORTED */ #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) /* Function to allocate memory for zlib and clear it to 0. */ voidpf /* PRIVATE */ png_zalloc(voidpf png_ptr, uInt items, uInt size) { png_voidp ptr; png_structp p=(png_structp)png_ptr; png_uint_32 save_flags=p->flags; png_alloc_size_t num_bytes; if (png_ptr == NULL) return (NULL); if (items > PNG_UINT_32_MAX/size) { png_warning (p, "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); } /* Function to free memory for zlib */ void /* PRIVATE */ png_zfree(voidpf png_ptr, voidpf ptr) { png_free((png_structp)png_ptr, (png_voidp)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_ptr->crc = crc32(0, Z_NULL, 0); } /* Calculate the CRC over a section of data. We can only pass as * much data to this routine as the largest single buffer size. We * also check that this data will actually be used before going to the * trouble of calculating it. */ void /* PRIVATE */ png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length) { int need_crc = 1; if (png_ptr->chunk_name[0] & 0x20) /* ancillary */ { if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) need_crc = 0; } else /* critical */ { if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) need_crc = 0; } if (need_crc) png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length); } /* 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. */ png_infop PNGAPI png_create_info_struct(png_structp png_ptr) { png_infop info_ptr; png_debug(1, "in png_create_info_struct"); if (png_ptr == NULL) return (NULL); #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)); 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. */ void PNGAPI png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr) { png_infop info_ptr = NULL; png_debug(1, "in png_destroy_info_struct"); if (png_ptr == NULL) return; if (info_ptr_ptr != NULL) info_ptr = *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 *info_ptr_ptr = NULL; } } /* 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. */ void PNGAPI png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size) { png_infop 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) { png_destroy_struct(info_ptr); info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); *ptr_ptr = info_ptr; } /* Set everything to 0 */ png_memset(info_ptr, 0, png_sizeof(png_info)); } void PNGAPI png_data_freer(png_structp png_ptr, png_infop info_ptr, int freer, png_uint_32 mask) { png_debug(1, "in png_data_freer"); if (png_ptr == NULL || info_ptr == NULL) return; if (freer == PNG_DESTROY_WILL_FREE_DATA) info_ptr->free_me |= mask; else if (freer == PNG_USER_WILL_FREE_DATA) info_ptr->free_me &= ~mask; else png_warning(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, int num) { png_debug(1, "in png_free_data"); if (png_ptr == NULL || info_ptr == NULL) return; #ifdef PNG_TEXT_SUPPORTED /* Free text item num or (if num == -1) all text items */ if ((mask & PNG_FREE_TEXT) & info_ptr->free_me) { if (num != -1) { if (info_ptr->text && info_ptr->text[num].key) { png_free(png_ptr, info_ptr->text[num].key); info_ptr->text[num].key = NULL; } } else { int i; for (i = 0; i < info_ptr->num_text; i++) png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i); png_free(png_ptr, info_ptr->text); info_ptr->text = NULL; info_ptr->num_text=0; } } #endif #ifdef PNG_tRNS_SUPPORTED /* Free any tRNS entry */ if ((mask & PNG_FREE_TRNS) & info_ptr->free_me) { png_free(png_ptr, info_ptr->trans_alpha); info_ptr->trans_alpha = NULL; info_ptr->valid &= ~PNG_INFO_tRNS; } #endif #ifdef PNG_sCAL_SUPPORTED /* Free any sCAL entry */ if ((mask & PNG_FREE_SCAL) & info_ptr->free_me) { #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED) png_free(png_ptr, info_ptr->scal_s_width); png_free(png_ptr, info_ptr->scal_s_height); info_ptr->scal_s_width = NULL; info_ptr->scal_s_height = NULL; #endif info_ptr->valid &= ~PNG_INFO_sCAL; } #endif #ifdef PNG_pCAL_SUPPORTED /* Free any pCAL entry */ if ((mask & PNG_FREE_PCAL) & info_ptr->free_me) { png_free(png_ptr, info_ptr->pcal_purpose); png_free(png_ptr, info_ptr->pcal_units); info_ptr->pcal_purpose = NULL; info_ptr->pcal_units = NULL; if (info_ptr->pcal_params != NULL) { int i; for (i = 0; i < (int)info_ptr->pcal_nparams; i++) { png_free(png_ptr, info_ptr->pcal_params[i]); info_ptr->pcal_params[i] = NULL; } png_free(png_ptr, info_ptr->pcal_params); info_ptr->pcal_params = NULL; } info_ptr->valid &= ~PNG_INFO_pCAL; } #endif #ifdef PNG_iCCP_SUPPORTED /* Free any iCCP entry */ if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) { png_free(png_ptr, info_ptr->iccp_name); png_free(png_ptr, info_ptr->iccp_profile); info_ptr->iccp_name = NULL; info_ptr->iccp_profile = NULL; info_ptr->valid &= ~PNG_INFO_iCCP; } #endif #ifdef PNG_sPLT_SUPPORTED /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ if ((mask & PNG_FREE_SPLT) & info_ptr->free_me) { if (num != -1) { if (info_ptr->splt_palettes) { png_free(png_ptr, info_ptr->splt_palettes[num].name); png_free(png_ptr, info_ptr->splt_palettes[num].entries); info_ptr->splt_palettes[num].name = NULL; info_ptr->splt_palettes[num].entries = NULL; } } else { 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); png_free(png_ptr, info_ptr->splt_palettes); info_ptr->splt_palettes = NULL; info_ptr->splt_palettes_num = 0; } info_ptr->valid &= ~PNG_INFO_sPLT; } } #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; } if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) { if (num != -1) { if (info_ptr->unknown_chunks) { png_free(png_ptr, info_ptr->unknown_chunks[num].data); info_ptr->unknown_chunks[num].data = NULL; } } else { int i; if (info_ptr->unknown_chunks_num) { for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++) png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i); png_free(png_ptr, info_ptr->unknown_chunks); info_ptr->unknown_chunks = NULL; info_ptr->unknown_chunks_num = 0; } } } #endif #ifdef PNG_hIST_SUPPORTED /* Free any hIST entry */ if ((mask & PNG_FREE_HIST) & info_ptr->free_me) { png_free(png_ptr, info_ptr->hist); info_ptr->hist = NULL; info_ptr->valid &= ~PNG_INFO_hIST; } #endif /* Free any PLTE entry that was internally allocated */ if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) { png_zfree(png_ptr, info_ptr->palette); info_ptr->palette = NULL; info_ptr->valid &= ~PNG_INFO_PLTE; info_ptr->num_palette = 0; } #ifdef PNG_INFO_IMAGE_SUPPORTED /* Free any image bits attached to the info structure */ if ((mask & PNG_FREE_ROWS) & info_ptr->free_me) { if (info_ptr->row_pointers) { int row; for (row = 0; row < (int)info_ptr->height; row++) { png_free(png_ptr, info_ptr->row_pointers[row]); info_ptr->row_pointers[row] = NULL; } png_free(png_ptr, info_ptr->row_pointers); info_ptr->row_pointers = NULL; } info_ptr->valid &= ~PNG_INFO_IDAT; } #endif if (num == -1) info_ptr->free_me &= ~mask; else info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL); } /* 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 * functions. The application should free any memory associated with this * pointer before png_write_destroy() or png_read_destroy() are called. */ png_voidp PNGAPI png_get_io_ptr(png_structp png_ptr) { if (png_ptr == NULL) return (NULL); return (png_ptr->io_ptr); } #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) #ifdef PNG_STDIO_SUPPORTED /* Initialize the default input/output functions for the PNG file. If you * use your own read or write routines, you can call either png_set_read_fn() * or png_set_write_fn() instead of png_init_io(). If you have defined * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't * necessarily available. */ void PNGAPI png_init_io(png_structp png_ptr, png_FILE_p fp) { png_debug(1, "in png_init_io"); if (png_ptr == NULL) return; png_ptr->io_ptr = (png_voidp)fp; } #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_charp PNGAPI png_convert_to_rfc1123(png_structp png_ptr, png_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 (png_ptr->time_buffer == NULL) { png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29* png_sizeof(char))); } #ifdef USE_FAR_KEYWORD { char near_time_buf[29]; png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000", ptime->day % 32, short_months[(ptime->month - 1) % 12], ptime->year, ptime->hour % 24, ptime->minute % 60, ptime->second % 61); png_memcpy(png_ptr->time_buffer, near_time_buf, 29*png_sizeof(char)); } #else png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000", ptime->day % 32, short_months[(ptime->month - 1) % 12], ptime->year, ptime->hour % 24, ptime->minute % 60, ptime->second % 61); #endif return ((png_charp)png_ptr->time_buffer); } #endif /* PNG_TIME_RFC1123_SUPPORTED */ #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ png_charp PNGAPI png_get_copyright(png_structp png_ptr) { png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ #ifdef PNG_STRING_COPYRIGHT return PNG_STRING_COPYRIGHT #else #ifdef __STDC__ return ((png_charp) PNG_STRING_NEWLINE \ "libpng version 1.4.2rc03 - April 16, 2010" PNG_STRING_NEWLINE \ "Copyright (c) 1998-2010 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 ((png_charp) "libpng version 1.4.2rc03 - April 16, 2010\ Copyright (c) 1998-2010 Glenn Randers-Pehrson\ Copyright (c) 1996-1997 Andreas Dilger\ Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."); #endif #endif } /* The following return the library version as a short string in the * format 1.0.0 through 99.99.99zz. To get the version of *.h files * used with your application, print out PNG_LIBPNG_VER_STRING, which * is defined in png.h. * Note: now there is no difference between png_get_libpng_ver() and * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, * it is guaranteed that png.c uses the correct version of png.h. */ png_charp PNGAPI png_get_libpng_ver(png_structp png_ptr) { /* Version of *.c files used when building libpng */ png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ return ((png_charp) PNG_LIBPNG_VER_STRING); } png_charp PNGAPI png_get_header_ver(png_structp png_ptr) { /* Version of *.h files used when building libpng */ png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ return ((png_charp) PNG_LIBPNG_VER_STRING); } png_charp PNGAPI png_get_header_version(png_structp png_ptr) { /* Returns longer string containing both version and date */ png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ #ifdef __STDC__ return ((png_charp) PNG_HEADER_VERSION_STRING #ifndef PNG_READ_SUPPORTED " (NO READ SUPPORT)" #endif PNG_STRING_NEWLINE); #else return ((png_charp) PNG_HEADER_VERSION_STRING); #endif } #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED int PNGAPI png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name) { /* Check chunk_name and return "keep" value if it's on the list, else 0 */ int i; png_bytep p; if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0) return 0; p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5; for (i = png_ptr->num_chunk_list; i; i--, p -= 5) if (!png_memcmp(chunk_name, p, 4)) return ((int)*(p + 4)); return 0; } #endif /* This function, added to libpng-1.0.6g, is untested. */ int PNGAPI png_reset_zstream(png_structp png_ptr) { if (png_ptr == NULL) return Z_STREAM_ERROR; return (inflateReset(&png_ptr->zstream)); } #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ /* This function was added to libpng-1.0.7 */ png_uint_32 PNGAPI png_access_version_number(void) { /* Version of *.c files used when building libpng */ return((png_uint_32) PNG_LIBPNG_VER); } #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) #ifdef PNG_SIZE_T /* Added at libpng version 1.2.6 */ PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size)); png_size_t PNGAPI png_convert_size(size_t size) { if (size > (png_size_t)-1) PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */ return ((png_size_t)size); } #endif /* PNG_SIZE_T */ /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ #ifdef PNG_cHRM_SUPPORTED #ifdef PNG_CHECK_cHRM_SUPPORTED /* * 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; } 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) { int ret = 1; unsigned long xy_hi,xy_lo,yx_hi,yx_lo; png_debug(1, "in function png_check_cHRM_fixed"); if (png_ptr == NULL) return 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; } if (white_x > (png_fixed_point) PNG_UINT_31_MAX || white_y > (png_fixed_point) PNG_UINT_31_MAX || red_x > (png_fixed_point) PNG_UINT_31_MAX || red_y > (png_fixed_point) PNG_UINT_31_MAX || green_x > (png_fixed_point) PNG_UINT_31_MAX || green_y > (png_fixed_point) PNG_UINT_31_MAX || blue_x > (png_fixed_point) PNG_UINT_31_MAX || blue_y > (png_fixed_point) PNG_UINT_31_MAX ) { png_warning(png_ptr, "Ignoring attempt to set chromaticity value exceeding 21474.83"); ret = 0; } if (white_x > 100000L - white_y) { png_warning(png_ptr, "Invalid cHRM white point"); ret = 0; } if (red_x > 100000L - red_y) { png_warning(png_ptr, "Invalid cHRM red point"); ret = 0; } if (green_x > 100000L - green_y) { png_warning(png_ptr, "Invalid cHRM green point"); ret = 0; } if (blue_x > 100000L - blue_y) { png_warning(png_ptr, "Invalid cHRM blue point"); ret = 0; } 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); 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; } return ret; } #endif /* PNG_CHECK_cHRM_SUPPORTED */ #endif /* PNG_cHRM_SUPPORTED */ void /* PRIVATE */ png_check_IHDR(png_structp 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) { int error = 0; /* Check for width and height valid values */ if (width == 0) { png_warning(png_ptr, "Image width is zero in IHDR"); error = 1; } if (height == 0) { png_warning(png_ptr, "Image height is zero in IHDR"); error = 1; } #ifdef PNG_SET_USER_LIMITS_SUPPORTED if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX) #else if (width > PNG_USER_WIDTH_MAX) #endif { png_warning(png_ptr, "Image width exceeds user limit in IHDR"); error = 1; } #ifdef PNG_SET_USER_LIMITS_SUPPORTED if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX) #else if (height > PNG_USER_HEIGHT_MAX) #endif { png_warning(png_ptr, "Image height exceeds user limit in IHDR"); error = 1; } if (width > PNG_UINT_31_MAX) { png_warning(png_ptr, "Invalid image width in IHDR"); error = 1; } if ( height > PNG_UINT_31_MAX) { png_warning(png_ptr, "Invalid image height in IHDR"); error = 1; } if ( width > (PNG_UINT_32_MAX >> 3) /* 8-byte RGBA pixels */ - 64 /* bigrowbuf hack */ - 1 /* filter byte */ - 7*8 /* rounding of width to multiple of 8 pixels */ - 8) /* extra max_pixel_depth pad */ png_warning(png_ptr, "Width is too large for libpng to process pixels"); /* Check other values */ if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && bit_depth != 8 && bit_depth != 16) { png_warning(png_ptr, "Invalid bit depth in IHDR"); error = 1; } if (color_type < 0 || color_type == 1 || color_type == 5 || color_type > 6) { png_warning(png_ptr, "Invalid color type in IHDR"); error = 1; } if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || ((color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_GRAY_ALPHA || color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) { png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); error = 1; } if (interlace_type >= PNG_INTERLACE_LAST) { png_warning(png_ptr, "Unknown interlace method in IHDR"); error = 1; } if (compression_type != PNG_COMPRESSION_TYPE_BASE) { png_warning(png_ptr, "Unknown compression method in IHDR"); error = 1; } #ifdef PNG_MNG_FEATURES_SUPPORTED /* Accept filter_method 64 (intrapixel differencing) only if * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and * 2. Libpng did not read a PNG signature (this filter_method is only * used in PNG datastreams that are embedded in MNG datastreams) and * 3. The application called png_permit_mng_features with a mask that * included PNG_FLAG_MNG_FILTER_64 and * 4. The filter_method is 64 and * 5. The color_type is RGB or RGBA */ if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) && png_ptr->mng_features_permitted) png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); if (filter_type != PNG_FILTER_TYPE_BASE) { if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA))) { png_warning(png_ptr, "Unknown filter method in IHDR"); error = 1; } if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) { png_warning(png_ptr, "Invalid filter method in IHDR"); error = 1; } } #else if (filter_type != PNG_FILTER_TYPE_BASE) { png_warning(png_ptr, "Unknown filter method in IHDR"); error = 1; } #endif if (error == 1) png_error(png_ptr, "Invalid IHDR data"); } #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */