diff options
Diffstat (limited to 'klibc/klibc/vsscanf.c')
-rw-r--r-- | klibc/klibc/vsscanf.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/klibc/klibc/vsscanf.c b/klibc/klibc/vsscanf.c new file mode 100644 index 0000000000..12a82b2747 --- /dev/null +++ b/klibc/klibc/vsscanf.c @@ -0,0 +1,365 @@ +/* + * vsscanf.c + * + * vsscanf(), from which the rest of the scanf() + * family is built + */ + +#include <ctype.h> +#include <stdarg.h> +#include <stddef.h> +#include <inttypes.h> +#include <string.h> +#include <limits.h> +#include <stdio.h> + +#ifndef LONG_BIT +#define LONG_BIT (CHAR_BIT*sizeof(long)) +#endif + +enum flags { + FL_SPLAT = 0x01, /* Drop the value, do not assign */ + FL_INV = 0x02, /* Character-set with inverse */ + FL_WIDTH = 0x04, /* Field width specified */ + FL_MINUS = 0x08, /* Negative number */ +}; + +enum ranks { + rank_char = -2, + rank_short = -1, + rank_int = 0, + rank_long = 1, + rank_longlong = 2, + rank_ptr = INT_MAX /* Special value used for pointers */ +}; + +#define MIN_RANK rank_char +#define MAX_RANK rank_longlong + +#define INTMAX_RANK rank_longlong +#define SIZE_T_RANK rank_long +#define PTRDIFF_T_RANK rank_long + +enum bail { + bail_none = 0, /* No error condition */ + bail_eof, /* Hit EOF */ + bail_err /* Conversion mismatch */ +}; + +static inline const char * +skipspace(const char *p) +{ + while ( isspace((unsigned char)*p) ) p++; + return p; +} + +#undef set_bit +static inline void +set_bit(unsigned long *bitmap, unsigned int bit) +{ + bitmap[bit/LONG_BIT] |= 1UL << (bit%LONG_BIT); +} + +#undef test_bit +static inline int +test_bit(unsigned long *bitmap, unsigned int bit) +{ + return (int)(bitmap[bit/LONG_BIT] >> (bit%LONG_BIT)) & 1; +} + +int vsscanf(const char *buffer, const char *format, va_list ap) +{ + const char *p = format; + char ch; + const char *q = buffer; + const char *qq; + uintmax_t val = 0; + int rank = rank_int; /* Default rank */ + unsigned int width = UINT_MAX; + int base; + enum flags flags = 0; + enum { + st_normal, /* Ground state */ + st_flags, /* Special flags */ + st_width, /* Field width */ + st_modifiers, /* Length or conversion modifiers */ + st_match_init, /* Initial state of %[ sequence */ + st_match, /* Main state of %[ sequence */ + st_match_range, /* After - in a %[ sequence */ + } state = st_normal; + char *sarg = NULL; /* %s %c or %[ string argument */ + enum bail bail = bail_none; + int sign; + int converted = 0; /* Successful conversions */ + unsigned long matchmap[((1 << CHAR_BIT)+(LONG_BIT-1))/LONG_BIT]; + int matchinv = 0; /* Is match map inverted? */ + unsigned char range_start = 0; + + while ( (ch = *p++) && !bail ) { + switch ( state ) { + case st_normal: + if ( ch == '%' ) { + state = st_flags; + flags = 0; rank = rank_int; width = UINT_MAX; + } else if ( isspace((unsigned char)ch) ) { + q = skipspace(q); + } else { + if ( *q == ch ) + q++; + else + bail = bail_err; /* Match failure */ + } + break; + + case st_flags: + switch ( ch ) { + case '*': + flags |= FL_SPLAT; + break; + case '0' ... '9': + width = (ch-'0'); + state = st_width; + flags |= FL_WIDTH; + break; + default: + state = st_modifiers; + p--; /* Process this character again */ + break; + } + break; + + case st_width: + if ( ch >= '0' && ch <= '9' ) { + width = width*10+(ch-'0'); + } else { + state = st_modifiers; + p--; /* Process this character again */ + } + break; + + case st_modifiers: + switch ( ch ) { + /* Length modifiers - nonterminal sequences */ + case 'h': + rank--; /* Shorter rank */ + break; + case 'l': + rank++; /* Longer rank */ + break; + case 'j': + rank = INTMAX_RANK; + break; + case 'z': + rank = SIZE_T_RANK; + break; + case 't': + rank = PTRDIFF_T_RANK; + break; + case 'L': + case 'q': + rank = rank_longlong; /* long double/long long */ + break; + + default: + /* Output modifiers - terminal sequences */ + state = st_normal; /* Next state will be normal */ + if ( rank < MIN_RANK ) /* Canonicalize rank */ + rank = MIN_RANK; + else if ( rank > MAX_RANK ) + rank = MAX_RANK; + + switch ( ch ) { + case 'P': /* Upper case pointer */ + case 'p': /* Pointer */ +#if 0 /* Enable this to allow null pointers by name */ + q = skipspace(q); + if ( !isdigit((unsigned char)*q) ) { + static const char * const nullnames[] = + { "null", "nul", "nil", "(null)", "(nul)", "(nil)", 0 }; + const char * const *np; + + /* Check to see if it's a null pointer by name */ + for ( np = nullnames ; *np ; np++ ) { + if ( !strncasecmp(q, *np, strlen(*np)) ) { + val = (uintmax_t)((void *)NULL); + goto set_integer; + } + } + /* Failure */ + bail = bail_err; + break; + } + /* else */ +#endif + rank = rank_ptr; + base = 0; sign = 0; + goto scan_int; + + case 'i': /* Base-independent integer */ + base = 0; sign = 1; + goto scan_int; + + case 'd': /* Decimal integer */ + base = 10; sign = 1; + goto scan_int; + + case 'o': /* Octal integer */ + base = 8; sign = 0; + goto scan_int; + + case 'u': /* Unsigned decimal integer */ + base = 10; sign = 0; + goto scan_int; + + case 'x': /* Hexadecimal integer */ + case 'X': + base = 16; sign = 0; + goto scan_int; + + case 'n': /* Number of characters consumed */ + val = (q-buffer); + goto set_integer; + + scan_int: + q = skipspace(q); + if ( !*q ) { + bail = bail_eof; + break; + } + val = strntoumax(q, (char **)&qq, base, width); + if ( qq == q ) { + bail = bail_err; + break; + } + q = qq; + converted++; + /* fall through */ + + set_integer: + if ( !(flags & FL_SPLAT) ) { + switch(rank) { + case rank_char: + *va_arg(ap, unsigned char *) = (unsigned char)val; + break; + case rank_short: + *va_arg(ap, unsigned short *) = (unsigned short)val; + break; + case rank_int: + *va_arg(ap, unsigned int *) = (unsigned int)val; + break; + case rank_long: + *va_arg(ap, unsigned long *) = (unsigned long)val; + break; + case rank_longlong: + *va_arg(ap, unsigned long long *) = (unsigned long long)val; + break; + case rank_ptr: + *va_arg(ap, void **) = (void *)(uintptr_t)val; + break; + } + } + break; + + case 'c': /* Character */ + width = (flags & FL_WIDTH) ? width : 1; /* Default width == 1 */ + sarg = va_arg(ap, char *); + while ( width-- ) { + if ( !*q ) { + bail = bail_eof; + break; + } + *sarg++ = *q++; + } + if ( !bail ) + converted++; + break; + + case 's': /* String */ + { + char *sp; + sp = sarg = va_arg(ap, char *); + while ( width-- && *q && !isspace((unsigned char)*q) ) { + *sp++ = *q++; + } + if ( sarg != sp ) { + *sp = '\0'; /* Terminate output */ + converted++; + } else { + bail = bail_eof; + } + } + break; + + case '[': /* Character range */ + sarg = va_arg(ap, char *); + state = st_match_init; + matchinv = 0; + memset(matchmap, 0, sizeof matchmap); + break; + + case '%': /* %% sequence */ + if ( *q == '%' ) + q++; + else + bail = bail_err; + break; + + default: /* Anything else */ + bail = bail_err; /* Unknown sequence */ + break; + } + } + break; + + case st_match_init: /* Initial state for %[ match */ + if ( ch == '^' && !(flags & FL_INV) ) { + matchinv = 1; + } else { + set_bit(matchmap, (unsigned char)ch); + state = st_match; + } + break; + + case st_match: /* Main state for %[ match */ + if ( ch == ']' ) { + goto match_run; + } else if ( ch == '-' ) { + range_start = (unsigned char)ch; + state = st_match_range; + } else { + set_bit(matchmap, (unsigned char)ch); + } + break; + + case st_match_range: /* %[ match after - */ + if ( ch == ']' ) { + set_bit(matchmap, (unsigned char)'-'); /* - was last character */ + goto match_run; + } else { + int i; + for ( i = range_start ; i < (unsigned char)ch ; i++ ) + set_bit(matchmap, i); + state = st_match; + } + break; + + match_run: /* Match expression finished */ + qq = q; + while ( width && *q && test_bit(matchmap, (unsigned char)*q)^matchinv ) { + *sarg++ = *q++; + } + if ( q != qq ) { + *sarg = '\0'; + converted++; + } else { + bail = *q ? bail_err : bail_eof; + } + break; + } + } + + if ( bail == bail_eof && !converted ) + converted = -1; /* Return EOF (-1) */ + + return converted; +} |