1 /* 2 * vsscanf.c 3 * 4 * vsscanf(), from which the rest of the scanf() 5 * family is built 6 */ 7 8 #include <ctype.h> 9 #include <stdarg.h> 10 #include <stddef.h> 11 #include <inttypes.h> 12 #include <string.h> 13 #include <limits.h> 14 #include <stdio.h> 15 #include <sys/bitops.h> 16 17 #ifndef LONG_BIT 18 #define LONG_BIT (CHAR_BIT*sizeof(long)) 19 #endif 20 21 enum flags { 22 FL_SPLAT = 0x01, /* Drop the value, do not assign */ 23 FL_WIDTH = 0x02, /* Field width specified */ 24 FL_MINUS = 0x04, /* Negative number */ 25 }; 26 27 enum ranks { 28 rank_char = -2, 29 rank_short = -1, 30 rank_int = 0, 31 rank_long = 1, 32 rank_longlong = 2, 33 rank_ptr = INT_MAX /* Special value used for pointers */ 34 }; 35 36 #define MIN_RANK rank_char 37 #define MAX_RANK rank_longlong 38 39 #define INTMAX_RANK rank_longlong 40 #define SIZE_T_RANK rank_long 41 #define PTRDIFF_T_RANK rank_long 42 43 enum bail { 44 bail_none = 0, /* No error condition */ 45 bail_eof, /* Hit EOF */ 46 bail_err /* Conversion mismatch */ 47 }; 48 49 int vsscanf(const char *buffer, const char *format, va_list ap) 50 { 51 const char *p = format; 52 char ch; 53 const char *q = buffer; 54 const char *qq; 55 uintmax_t val = 0; 56 int rank = rank_int; /* Default rank */ 57 unsigned int width = UINT_MAX; 58 int base; 59 enum flags flags = 0; 60 enum { 61 st_normal, /* Ground state */ 62 st_flags, /* Special flags */ 63 st_width, /* Field width */ 64 st_modifiers, /* Length or conversion modifiers */ 65 st_match_init, /* Initial state of %[ sequence */ 66 st_match, /* Main state of %[ sequence */ 67 st_match_range, /* After - in a %[ sequence */ 68 } state = st_normal; 69 char *sarg = NULL; /* %s %c or %[ string argument */ 70 enum bail bail = bail_none; 71 int converted = 0; /* Successful conversions */ 72 unsigned long matchmap[((1 << CHAR_BIT) + (LONG_BIT - 1)) / LONG_BIT]; 73 int matchinv = 0; /* Is match map inverted? */ 74 unsigned char range_start = 0; 75 76 while ((ch = *p++) && !bail) { 77 switch (state) { 78 case st_normal: 79 if (ch == '%') { 80 state = st_flags; 81 flags = 0; 82 rank = rank_int; 83 width = UINT_MAX; 84 } else if (isspace((unsigned char)ch)) { 85 q = skipspace(q); 86 } else { 87 if (*q == ch) 88 q++; 89 else 90 bail = bail_err; /* Match failure */ 91 } 92 break; 93 94 case st_flags: 95 switch (ch) { 96 case '*': 97 flags |= FL_SPLAT; 98 break; 99 case '0' ... '9': 100 width = (ch - '0'); 101 state = st_width; 102 flags |= FL_WIDTH; 103 break; 104 default: 105 state = st_modifiers; 106 p--; /* Process this character again */ 107 break; 108 } 109 break; 110 111 case st_width: 112 if (ch >= '0' && ch <= '9') { 113 width = width * 10 + (ch - '0'); 114 } else { 115 state = st_modifiers; 116 p--; /* Process this character again */ 117 } 118 break; 119 120 case st_modifiers: 121 switch (ch) { 122 /* Length modifiers - nonterminal sequences */ 123 case 'h': 124 rank--; /* Shorter rank */ 125 break; 126 case 'l': 127 rank++; /* Longer rank */ 128 break; 129 case 'j': 130 rank = INTMAX_RANK; 131 break; 132 case 'z': 133 rank = SIZE_T_RANK; 134 break; 135 case 't': 136 rank = PTRDIFF_T_RANK; 137 break; 138 case 'L': 139 case 'q': 140 rank = rank_longlong; /* long double/long long */ 141 break; 142 143 default: 144 /* Output modifiers - terminal sequences */ 145 state = st_normal; /* Next state will be normal */ 146 if (rank < MIN_RANK) /* Canonicalize rank */ 147 rank = MIN_RANK; 148 else if (rank > MAX_RANK) 149 rank = MAX_RANK; 150 151 switch (ch) { 152 case 'P': /* Upper case pointer */ 153 case 'p': /* Pointer */ 154 #if 0 /* Enable this to allow null pointers by name */ 155 q = skipspace(q); 156 if (!isdigit((unsigned char)*q)) { 157 static const char *const nullnames[] = 158 { "null", "nul", "nil", "(null)", "(nul)", "(nil)", 159 0 }; 160 const char *const *np; 161 162 /* Check to see if it's a null pointer by name */ 163 for (np = nullnames; *np; np++) { 164 if (!strncasecmp(q, *np, strlen(*np))) { 165 val = (uintmax_t) ((void *)NULL); 166 goto set_integer; 167 } 168 } 169 /* Failure */ 170 bail = bail_err; 171 break; 172 } 173 /* else */ 174 #endif 175 rank = rank_ptr; 176 base = 0; 177 goto scan_int; 178 179 case 'i': /* Base-independent integer */ 180 base = 0; 181 goto scan_int; 182 183 case 'd': /* Decimal integer */ 184 base = 10; 185 goto scan_int; 186 187 case 'o': /* Octal integer */ 188 base = 8; 189 goto scan_int; 190 191 case 'u': /* Unsigned decimal integer */ 192 base = 10; 193 goto scan_int; 194 195 case 'x': /* Hexadecimal integer */ 196 case 'X': 197 base = 16; 198 goto scan_int; 199 200 case 'n': /* Number of characters consumed */ 201 val = (q - buffer); 202 goto set_integer; 203 204 scan_int: 205 q = skipspace(q); 206 if (!*q) { 207 bail = bail_eof; 208 break; 209 } 210 val = strntoumax(q, (char **)&qq, base, width); 211 if (qq == q) { 212 bail = bail_err; 213 break; 214 } 215 q = qq; 216 converted++; 217 /* fall through */ 218 219 set_integer: 220 if (!(flags & FL_SPLAT)) { 221 switch (rank) { 222 case rank_char: 223 *va_arg(ap, unsigned char *) = (unsigned char)val; 224 break; 225 case rank_short: 226 *va_arg(ap, unsigned short *) = (unsigned short)val; 227 break; 228 case rank_int: 229 *va_arg(ap, unsigned int *) = (unsigned int)val; 230 break; 231 case rank_long: 232 *va_arg(ap, unsigned long *) = (unsigned long)val; 233 break; 234 case rank_longlong: 235 *va_arg(ap, unsigned long long *) = 236 (unsigned long long)val; 237 break; 238 case rank_ptr: 239 *va_arg(ap, void **) = (void *)(uintptr_t) val; 240 break; 241 } 242 } 243 break; 244 245 case 'c': /* Character */ 246 width = (flags & FL_WIDTH) ? width : 1; /* Default width == 1 */ 247 sarg = va_arg(ap, char *); 248 while (width--) { 249 if (!*q) { 250 bail = bail_eof; 251 break; 252 } 253 *sarg++ = *q++; 254 } 255 if (!bail) 256 converted++; 257 break; 258 259 case 's': /* String */ 260 { 261 char *sp; 262 sp = sarg = va_arg(ap, char *); 263 while (width-- && *q && !isspace((unsigned char)*q)) { 264 *sp++ = *q++; 265 } 266 if (sarg != sp) { 267 *sp = '\0'; /* Terminate output */ 268 converted++; 269 } else { 270 bail = bail_eof; 271 } 272 } 273 break; 274 275 case '[': /* Character range */ 276 sarg = va_arg(ap, char *); 277 state = st_match_init; 278 matchinv = 0; 279 memset(matchmap, 0, sizeof matchmap); 280 break; 281 282 case '%': /* %% sequence */ 283 if (*q == '%') 284 q++; 285 else 286 bail = bail_err; 287 break; 288 289 default: /* Anything else */ 290 bail = bail_err; /* Unknown sequence */ 291 break; 292 } 293 } 294 break; 295 296 case st_match_init: /* Initial state for %[ match */ 297 if (ch == '^' && !matchinv) { 298 matchinv = 1; 299 } else { 300 range_start = (unsigned char)ch; 301 set_bit((unsigned char)ch, matchmap); 302 state = st_match; 303 } 304 break; 305 306 case st_match: /* Main state for %[ match */ 307 if (ch == ']') { 308 goto match_run; 309 } else if (ch == '-') { 310 state = st_match_range; 311 } else { 312 range_start = (unsigned char)ch; 313 set_bit((unsigned char)ch, matchmap); 314 } 315 break; 316 317 case st_match_range: /* %[ match after - */ 318 if (ch == ']') { 319 set_bit((unsigned char)'-', matchmap); /* - was last character */ 320 goto match_run; 321 } else { 322 int i; 323 for (i = range_start; i <= (unsigned char)ch; i++) 324 set_bit(i, matchmap); 325 state = st_match; 326 } 327 break; 328 329 match_run: /* Match expression finished */ 330 qq = q; 331 while (width && *q 332 && test_bit((unsigned char)*q, matchmap) ^ matchinv) { 333 *sarg++ = *q++; 334 } 335 if (q != qq) { 336 *sarg = '\0'; 337 converted++; 338 } else { 339 bail = *q ? bail_err : bail_eof; 340 } 341 break; 342 } 343 } 344 345 if (bail == bail_eof && !converted) 346 converted = -1; /* Return EOF (-1) */ 347 348 return converted; 349 } 350
