linux/lib/vsprintf.c
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   1/*
   2 *  linux/lib/vsprintf.c
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 */
   6
   7/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
   8/*
   9 * Wirzenius wrote this portably, Torvalds fucked it up :-)
  10 */
  11
  12/* 
  13 * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
  14 * - changed to provide snprintf and vsnprintf functions
  15 * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
  16 * - scnprintf and vscnprintf
  17 */
  18
  19#include <stdarg.h>
  20#include <linux/module.h>
  21#include <linux/types.h>
  22#include <linux/string.h>
  23#include <linux/ctype.h>
  24#include <linux/kernel.h>
  25
  26#include <asm/page.h>           /* for PAGE_SIZE */
  27#include <asm/div64.h>
  28
  29/**
  30 * simple_strtoul - convert a string to an unsigned long
  31 * @cp: The start of the string
  32 * @endp: A pointer to the end of the parsed string will be placed here
  33 * @base: The number base to use
  34 */
  35unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
  36{
  37        unsigned long result = 0,value;
  38
  39        if (!base) {
  40                base = 10;
  41                if (*cp == '0') {
  42                        base = 8;
  43                        cp++;
  44                        if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
  45                                cp++;
  46                                base = 16;
  47                        }
  48                }
  49        } else if (base == 16) {
  50                if (cp[0] == '0' && toupper(cp[1]) == 'X')
  51                        cp += 2;
  52        }
  53        while (isxdigit(*cp) &&
  54               (value = isdigit(*cp) ? *cp-'0' : toupper(*cp)-'A'+10) < base) {
  55                result = result*base + value;
  56                cp++;
  57        }
  58        if (endp)
  59                *endp = (char *)cp;
  60        return result;
  61}
  62
  63EXPORT_SYMBOL(simple_strtoul);
  64
  65/**
  66 * simple_strtol - convert a string to a signed long
  67 * @cp: The start of the string
  68 * @endp: A pointer to the end of the parsed string will be placed here
  69 * @base: The number base to use
  70 */
  71long simple_strtol(const char *cp,char **endp,unsigned int base)
  72{
  73        if(*cp=='-')
  74                return -simple_strtoul(cp+1,endp,base);
  75        return simple_strtoul(cp,endp,base);
  76}
  77
  78EXPORT_SYMBOL(simple_strtol);
  79
  80/**
  81 * simple_strtoull - convert a string to an unsigned long long
  82 * @cp: The start of the string
  83 * @endp: A pointer to the end of the parsed string will be placed here
  84 * @base: The number base to use
  85 */
  86unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base)
  87{
  88        unsigned long long result = 0,value;
  89
  90        if (!base) {
  91                base = 10;
  92                if (*cp == '0') {
  93                        base = 8;
  94                        cp++;
  95                        if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
  96                                cp++;
  97                                base = 16;
  98                        }
  99                }
 100        } else if (base == 16) {
 101                if (cp[0] == '0' && toupper(cp[1]) == 'X')
 102                        cp += 2;
 103        }
 104        while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
 105            ? toupper(*cp) : *cp)-'A'+10) < base) {
 106                result = result*base + value;
 107                cp++;
 108        }
 109        if (endp)
 110                *endp = (char *)cp;
 111        return result;
 112}
 113
 114EXPORT_SYMBOL(simple_strtoull);
 115
 116/**
 117 * simple_strtoll - convert a string to a signed long long
 118 * @cp: The start of the string
 119 * @endp: A pointer to the end of the parsed string will be placed here
 120 * @base: The number base to use
 121 */
 122long long simple_strtoll(const char *cp,char **endp,unsigned int base)
 123{
 124        if(*cp=='-')
 125                return -simple_strtoull(cp+1,endp,base);
 126        return simple_strtoull(cp,endp,base);
 127}
 128
 129static int skip_atoi(const char **s)
 130{
 131        int i=0;
 132
 133        while (isdigit(**s))
 134                i = i*10 + *((*s)++) - '0';
 135        return i;
 136}
 137
 138/* Decimal conversion is by far the most typical, and is used
 139 * for /proc and /sys data. This directly impacts e.g. top performance
 140 * with many processes running. We optimize it for speed
 141 * using code from
 142 * http://www.cs.uiowa.edu/~jones/bcd/decimal.html
 143 * (with permission from the author, Douglas W. Jones). */
 144
 145/* Formats correctly any integer in [0,99999].
 146 * Outputs from one to five digits depending on input.
 147 * On i386 gcc 4.1.2 -O2: ~250 bytes of code. */
 148static char* put_dec_trunc(char *buf, unsigned q)
 149{
 150        unsigned d3, d2, d1, d0;
 151        d1 = (q>>4) & 0xf;
 152        d2 = (q>>8) & 0xf;
 153        d3 = (q>>12);
 154
 155        d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 156        q = (d0 * 0xcd) >> 11;
 157        d0 = d0 - 10*q;
 158        *buf++ = d0 + '0'; /* least significant digit */
 159        d1 = q + 9*d3 + 5*d2 + d1;
 160        if (d1 != 0) {
 161                q = (d1 * 0xcd) >> 11;
 162                d1 = d1 - 10*q;
 163                *buf++ = d1 + '0'; /* next digit */
 164
 165                d2 = q + 2*d2;
 166                if ((d2 != 0) || (d3 != 0)) {
 167                        q = (d2 * 0xd) >> 7;
 168                        d2 = d2 - 10*q;
 169                        *buf++ = d2 + '0'; /* next digit */
 170
 171                        d3 = q + 4*d3;
 172                        if (d3 != 0) {
 173                                q = (d3 * 0xcd) >> 11;
 174                                d3 = d3 - 10*q;
 175                                *buf++ = d3 + '0';  /* next digit */
 176                                if (q != 0)
 177                                        *buf++ = q + '0';  /* most sign. digit */
 178                        }
 179                }
 180        }
 181        return buf;
 182}
 183/* Same with if's removed. Always emits five digits */
 184static char* put_dec_full(char *buf, unsigned q)
 185{
 186        /* BTW, if q is in [0,9999], 8-bit ints will be enough, */
 187        /* but anyway, gcc produces better code with full-sized ints */
 188        unsigned d3, d2, d1, d0;
 189        d1 = (q>>4) & 0xf;
 190        d2 = (q>>8) & 0xf;
 191        d3 = (q>>12);
 192
 193        /* Possible ways to approx. divide by 10 */
 194        /* gcc -O2 replaces multiply with shifts and adds */
 195        // (x * 0xcd) >> 11: 11001101 - shorter code than * 0x67 (on i386)
 196        // (x * 0x67) >> 10:  1100111
 197        // (x * 0x34) >> 9:    110100 - same
 198        // (x * 0x1a) >> 8:     11010 - same
 199        // (x * 0x0d) >> 7:      1101 - same, shortest code (on i386)
 200
 201        d0 = 6*(d3 + d2 + d1) + (q & 0xf);
 202        q = (d0 * 0xcd) >> 11;
 203        d0 = d0 - 10*q;
 204        *buf++ = d0 + '0';
 205        d1 = q + 9*d3 + 5*d2 + d1;
 206                q = (d1 * 0xcd) >> 11;
 207                d1 = d1 - 10*q;
 208                *buf++ = d1 + '0';
 209
 210                d2 = q + 2*d2;
 211                        q = (d2 * 0xd) >> 7;
 212                        d2 = d2 - 10*q;
 213                        *buf++ = d2 + '0';
 214
 215                        d3 = q + 4*d3;
 216                                q = (d3 * 0xcd) >> 11; /* - shorter code */
 217                                /* q = (d3 * 0x67) >> 10; - would also work */
 218                                d3 = d3 - 10*q;
 219                                *buf++ = d3 + '0';
 220                                        *buf++ = q + '0';
 221        return buf;
 222}
 223/* No inlining helps gcc to use registers better */
 224static noinline char* put_dec(char *buf, unsigned long long num)
 225{
 226        while (1) {
 227                unsigned rem;
 228                if (num < 100000)
 229                        return put_dec_trunc(buf, num);
 230                rem = do_div(num, 100000);
 231                buf = put_dec_full(buf, rem);
 232        }
 233}
 234
 235#define ZEROPAD 1               /* pad with zero */
 236#define SIGN    2               /* unsigned/signed long */
 237#define PLUS    4               /* show plus */
 238#define SPACE   8               /* space if plus */
 239#define LEFT    16              /* left justified */
 240#define SPECIAL 32              /* 0x */
 241#define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
 242
 243static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type)
 244{
 245        char sign,tmp[66];
 246        const char *digits;
 247        /* we are called with base 8, 10 or 16, only, thus don't need "g..."  */
 248        static const char small_digits[] = "0123456789abcdefx"; /* "ghijklmnopqrstuvwxyz"; */
 249        static const char large_digits[] = "0123456789ABCDEFX"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
 250        int need_pfx = ((type & SPECIAL) && base != 10);
 251        int i;
 252
 253        digits = (type & LARGE) ? large_digits : small_digits;
 254        if (type & LEFT)
 255                type &= ~ZEROPAD;
 256        if (base < 2 || base > 36)
 257                return NULL;
 258        sign = 0;
 259        if (type & SIGN) {
 260                if ((signed long long) num < 0) {
 261                        sign = '-';
 262                        num = - (signed long long) num;
 263                        size--;
 264                } else if (type & PLUS) {
 265                        sign = '+';
 266                        size--;
 267                } else if (type & SPACE) {
 268                        sign = ' ';
 269                        size--;
 270                }
 271        }
 272        if (need_pfx) {
 273                size--;
 274                if (base == 16)
 275                        size--;
 276        }
 277
 278        /* generate full string in tmp[], in reverse order */
 279        i = 0;
 280        if (num == 0)
 281                tmp[i++] = '0';
 282        /* Generic code, for any base:
 283        else do {
 284                tmp[i++] = digits[do_div(num,base)];
 285        } while (num != 0);
 286        */
 287        else if (base != 10) { /* 8 or 16 */
 288                int mask = base - 1;
 289                int shift = 3;
 290                if (base == 16) shift = 4;
 291                do {
 292                        tmp[i++] = digits[((unsigned char)num) & mask];
 293                        num >>= shift;
 294                } while (num);
 295        } else { /* base 10 */
 296                i = put_dec(tmp, num) - tmp;
 297        }
 298
 299        /* printing 100 using %2d gives "100", not "00" */
 300        if (i > precision)
 301                precision = i;
 302        /* leading space padding */
 303        size -= precision;
 304        if (!(type & (ZEROPAD+LEFT))) {
 305                while(--size >= 0) {
 306                        if (buf < end)
 307                                *buf = ' ';
 308                        ++buf;
 309                }
 310        }
 311        /* sign */
 312        if (sign) {
 313                if (buf < end)
 314                        *buf = sign;
 315                ++buf;
 316        }
 317        /* "0x" / "0" prefix */
 318        if (need_pfx) {
 319                if (buf < end)
 320                        *buf = '0';
 321                ++buf;
 322                if (base == 16) {
 323                        if (buf < end)
 324                                *buf = digits[16]; /* for arbitrary base: digits[33]; */
 325                        ++buf;
 326                }
 327        }
 328        /* zero or space padding */
 329        if (!(type & LEFT)) {
 330                char c = (type & ZEROPAD) ? '0' : ' ';
 331                while (--size >= 0) {
 332                        if (buf < end)
 333                                *buf = c;
 334                        ++buf;
 335                }
 336        }
 337        /* hmm even more zero padding? */
 338        while (i <= --precision) {
 339                if (buf < end)
 340                        *buf = '0';
 341                ++buf;
 342        }
 343        /* actual digits of result */
 344        while (--i >= 0) {
 345                if (buf < end)
 346                        *buf = tmp[i];
 347                ++buf;
 348        }
 349        /* trailing space padding */
 350        while (--size >= 0) {
 351                if (buf < end)
 352                        *buf = ' ';
 353                ++buf;
 354        }
 355        return buf;
 356}
 357
 358/**
 359 * vsnprintf - Format a string and place it in a buffer
 360 * @buf: The buffer to place the result into
 361 * @size: The size of the buffer, including the trailing null space
 362 * @fmt: The format string to use
 363 * @args: Arguments for the format string
 364 *
 365 * The return value is the number of characters which would
 366 * be generated for the given input, excluding the trailing
 367 * '\0', as per ISO C99. If you want to have the exact
 368 * number of characters written into @buf as return value
 369 * (not including the trailing '\0'), use vscnprintf(). If the
 370 * return is greater than or equal to @size, the resulting
 371 * string is truncated.
 372 *
 373 * Call this function if you are already dealing with a va_list.
 374 * You probably want snprintf() instead.
 375 */
 376int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 377{
 378        int len;
 379        unsigned long long num;
 380        int i, base;
 381        char *str, *end, c;
 382        const char *s;
 383
 384        int flags;              /* flags to number() */
 385
 386        int field_width;        /* width of output field */
 387        int precision;          /* min. # of digits for integers; max
 388                                   number of chars for from string */
 389        int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 390                                /* 'z' support added 23/7/1999 S.H.    */
 391                                /* 'z' changed to 'Z' --davidm 1/25/99 */
 392                                /* 't' added for ptrdiff_t */
 393
 394        /* Reject out-of-range values early.  Large positive sizes are
 395           used for unknown buffer sizes. */
 396        if (unlikely((int) size < 0)) {
 397                /* There can be only one.. */
 398                static char warn = 1;
 399                WARN_ON(warn);
 400                warn = 0;
 401                return 0;
 402        }
 403
 404        str = buf;
 405        end = buf + size;
 406
 407        /* Make sure end is always >= buf */
 408        if (end < buf) {
 409                end = ((void *)-1);
 410                size = end - buf;
 411        }
 412
 413        for (; *fmt ; ++fmt) {
 414                if (*fmt != '%') {
 415                        if (str < end)
 416                                *str = *fmt;
 417                        ++str;
 418                        continue;
 419                }
 420
 421                /* process flags */
 422                flags = 0;
 423                repeat:
 424                        ++fmt;          /* this also skips first '%' */
 425                        switch (*fmt) {
 426                                case '-': flags |= LEFT; goto repeat;
 427                                case '+': flags |= PLUS; goto repeat;
 428                                case ' ': flags |= SPACE; goto repeat;
 429                                case '#': flags |= SPECIAL; goto repeat;
 430                                case '0': flags |= ZEROPAD; goto repeat;
 431                        }
 432
 433                /* get field width */
 434                field_width = -1;
 435                if (isdigit(*fmt))
 436                        field_width = skip_atoi(&fmt);
 437                else if (*fmt == '*') {
 438                        ++fmt;
 439                        /* it's the next argument */
 440                        field_width = va_arg(args, int);
 441                        if (field_width < 0) {
 442                                field_width = -field_width;
 443                                flags |= LEFT;
 444                        }
 445                }
 446
 447                /* get the precision */
 448                precision = -1;
 449                if (*fmt == '.') {
 450                        ++fmt;  
 451                        if (isdigit(*fmt))
 452                                precision = skip_atoi(&fmt);
 453                        else if (*fmt == '*') {
 454                                ++fmt;
 455                                /* it's the next argument */
 456                                precision = va_arg(args, int);
 457                        }
 458                        if (precision < 0)
 459                                precision = 0;
 460                }
 461
 462                /* get the conversion qualifier */
 463                qualifier = -1;
 464                if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 465                    *fmt =='Z' || *fmt == 'z' || *fmt == 't') {
 466                        qualifier = *fmt;
 467                        ++fmt;
 468                        if (qualifier == 'l' && *fmt == 'l') {
 469                                qualifier = 'L';
 470                                ++fmt;
 471                        }
 472                }
 473
 474                /* default base */
 475                base = 10;
 476
 477                switch (*fmt) {
 478                        case 'c':
 479                                if (!(flags & LEFT)) {
 480                                        while (--field_width > 0) {
 481                                                if (str < end)
 482                                                        *str = ' ';
 483                                                ++str;
 484                                        }
 485                                }
 486                                c = (unsigned char) va_arg(args, int);
 487                                if (str < end)
 488                                        *str = c;
 489                                ++str;
 490                                while (--field_width > 0) {
 491                                        if (str < end)
 492                                                *str = ' ';
 493                                        ++str;
 494                                }
 495                                continue;
 496
 497                        case 's':
 498                                s = va_arg(args, char *);
 499                                if ((unsigned long)s < PAGE_SIZE)
 500                                        s = "<NULL>";
 501
 502                                len = strnlen(s, precision);
 503
 504                                if (!(flags & LEFT)) {
 505                                        while (len < field_width--) {
 506                                                if (str < end)
 507                                                        *str = ' ';
 508                                                ++str;
 509                                        }
 510                                }
 511                                for (i = 0; i < len; ++i) {
 512                                        if (str < end)
 513                                                *str = *s;
 514                                        ++str; ++s;
 515                                }
 516                                while (len < field_width--) {
 517                                        if (str < end)
 518                                                *str = ' ';
 519                                        ++str;
 520                                }
 521                                continue;
 522
 523                        case 'p':
 524                                if (field_width == -1) {
 525                                        field_width = 2*sizeof(void *);
 526                                        flags |= ZEROPAD;
 527                                }
 528                                str = number(str, end,
 529                                                (unsigned long) va_arg(args, void *),
 530                                                16, field_width, precision, flags);
 531                                continue;
 532
 533
 534                        case 'n':
 535                                /* FIXME:
 536                                * What does C99 say about the overflow case here? */
 537                                if (qualifier == 'l') {
 538                                        long * ip = va_arg(args, long *);
 539                                        *ip = (str - buf);
 540                                } else if (qualifier == 'Z' || qualifier == 'z') {
 541                                        size_t * ip = va_arg(args, size_t *);
 542                                        *ip = (str - buf);
 543                                } else {
 544                                        int * ip = va_arg(args, int *);
 545                                        *ip = (str - buf);
 546                                }
 547                                continue;
 548
 549                        case '%':
 550                                if (str < end)
 551                                        *str = '%';
 552                                ++str;
 553                                continue;
 554
 555                                /* integer number formats - set up the flags and "break" */
 556                        case 'o':
 557                                base = 8;
 558                                break;
 559
 560                        case 'X':
 561                                flags |= LARGE;
 562                        case 'x':
 563                                base = 16;
 564                                break;
 565
 566                        case 'd':
 567                        case 'i':
 568                                flags |= SIGN;
 569                        case 'u':
 570                                break;
 571
 572                        default:
 573                                if (str < end)
 574                                        *str = '%';
 575                                ++str;
 576                                if (*fmt) {
 577                                        if (str < end)
 578                                                *str = *fmt;
 579                                        ++str;
 580                                } else {
 581                                        --fmt;
 582                                }
 583                                continue;
 584                }
 585                if (qualifier == 'L')
 586                        num = va_arg(args, long long);
 587                else if (qualifier == 'l') {
 588                        num = va_arg(args, unsigned long);
 589                        if (flags & SIGN)
 590                                num = (signed long) num;
 591                } else if (qualifier == 'Z' || qualifier == 'z') {
 592                        num = va_arg(args, size_t);
 593                } else if (qualifier == 't') {
 594                        num = va_arg(args, ptrdiff_t);
 595                } else if (qualifier == 'h') {
 596                        num = (unsigned short) va_arg(args, int);
 597                        if (flags & SIGN)
 598                                num = (signed short) num;
 599                } else {
 600                        num = va_arg(args, unsigned int);
 601                        if (flags & SIGN)
 602                                num = (signed int) num;
 603                }
 604                str = number(str, end, num, base,
 605                                field_width, precision, flags);
 606        }
 607        if (size > 0) {
 608                if (str < end)
 609                        *str = '\0';
 610                else
 611                        end[-1] = '\0';
 612        }
 613        /* the trailing null byte doesn't count towards the total */
 614        return str-buf;
 615}
 616
 617EXPORT_SYMBOL(vsnprintf);
 618
 619/**
 620 * vscnprintf - Format a string and place it in a buffer
 621 * @buf: The buffer to place the result into
 622 * @size: The size of the buffer, including the trailing null space
 623 * @fmt: The format string to use
 624 * @args: Arguments for the format string
 625 *
 626 * The return value is the number of characters which have been written into
 627 * the @buf not including the trailing '\0'. If @size is <= 0 the function
 628 * returns 0.
 629 *
 630 * Call this function if you are already dealing with a va_list.
 631 * You probably want scnprintf() instead.
 632 */
 633int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 634{
 635        int i;
 636
 637        i=vsnprintf(buf,size,fmt,args);
 638        return (i >= size) ? (size - 1) : i;
 639}
 640
 641EXPORT_SYMBOL(vscnprintf);
 642
 643/**
 644 * snprintf - Format a string and place it in a buffer
 645 * @buf: The buffer to place the result into
 646 * @size: The size of the buffer, including the trailing null space
 647 * @fmt: The format string to use
 648 * @...: Arguments for the format string
 649 *
 650 * The return value is the number of characters which would be
 651 * generated for the given input, excluding the trailing null,
 652 * as per ISO C99.  If the return is greater than or equal to
 653 * @size, the resulting string is truncated.
 654 */
 655int snprintf(char * buf, size_t size, const char *fmt, ...)
 656{
 657        va_list args;
 658        int i;
 659
 660        va_start(args, fmt);
 661        i=vsnprintf(buf,size,fmt,args);
 662        va_end(args);
 663        return i;
 664}
 665
 666EXPORT_SYMBOL(snprintf);
 667
 668/**
 669 * scnprintf - Format a string and place it in a buffer
 670 * @buf: The buffer to place the result into
 671 * @size: The size of the buffer, including the trailing null space
 672 * @fmt: The format string to use
 673 * @...: Arguments for the format string
 674 *
 675 * The return value is the number of characters written into @buf not including
 676 * the trailing '\0'. If @size is <= 0 the function returns 0.
 677 */
 678
 679int scnprintf(char * buf, size_t size, const char *fmt, ...)
 680{
 681        va_list args;
 682        int i;
 683
 684        va_start(args, fmt);
 685        i = vsnprintf(buf, size, fmt, args);
 686        va_end(args);
 687        return (i >= size) ? (size - 1) : i;
 688}
 689EXPORT_SYMBOL(scnprintf);
 690
 691/**
 692 * vsprintf - Format a string and place it in a buffer
 693 * @buf: The buffer to place the result into
 694 * @fmt: The format string to use
 695 * @args: Arguments for the format string
 696 *
 697 * The function returns the number of characters written
 698 * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
 699 * buffer overflows.
 700 *
 701 * Call this function if you are already dealing with a va_list.
 702 * You probably want sprintf() instead.
 703 */
 704int vsprintf(char *buf, const char *fmt, va_list args)
 705{
 706        return vsnprintf(buf, INT_MAX, fmt, args);
 707}
 708
 709EXPORT_SYMBOL(vsprintf);
 710
 711/**
 712 * sprintf - Format a string and place it in a buffer
 713 * @buf: The buffer to place the result into
 714 * @fmt: The format string to use
 715 * @...: Arguments for the format string
 716 *
 717 * The function returns the number of characters written
 718 * into @buf. Use snprintf() or scnprintf() in order to avoid
 719 * buffer overflows.
 720 */
 721int sprintf(char * buf, const char *fmt, ...)
 722{
 723        va_list args;
 724        int i;
 725
 726        va_start(args, fmt);
 727        i=vsnprintf(buf, INT_MAX, fmt, args);
 728        va_end(args);
 729        return i;
 730}
 731
 732EXPORT_SYMBOL(sprintf);
 733
 734/**
 735 * vsscanf - Unformat a buffer into a list of arguments
 736 * @buf:        input buffer
 737 * @fmt:        format of buffer
 738 * @args:       arguments
 739 */
 740int vsscanf(const char * buf, const char * fmt, va_list args)
 741{
 742        const char *str = buf;
 743        char *next;
 744        char digit;
 745        int num = 0;
 746        int qualifier;
 747        int base;
 748        int field_width;
 749        int is_sign = 0;
 750
 751        while(*fmt && *str) {
 752                /* skip any white space in format */
 753                /* white space in format matchs any amount of
 754                 * white space, including none, in the input.
 755                 */
 756                if (isspace(*fmt)) {
 757                        while (isspace(*fmt))
 758                                ++fmt;
 759                        while (isspace(*str))
 760                                ++str;
 761                }
 762
 763                /* anything that is not a conversion must match exactly */
 764                if (*fmt != '%' && *fmt) {
 765                        if (*fmt++ != *str++)
 766                                break;
 767                        continue;
 768                }
 769
 770                if (!*fmt)
 771                        break;
 772                ++fmt;
 773                
 774                /* skip this conversion.
 775                 * advance both strings to next white space
 776                 */
 777                if (*fmt == '*') {
 778                        while (!isspace(*fmt) && *fmt)
 779                                fmt++;
 780                        while (!isspace(*str) && *str)
 781                                str++;
 782                        continue;
 783                }
 784
 785                /* get field width */
 786                field_width = -1;
 787                if (isdigit(*fmt))
 788                        field_width = skip_atoi(&fmt);
 789
 790                /* get conversion qualifier */
 791                qualifier = -1;
 792                if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 793                    *fmt == 'Z' || *fmt == 'z') {
 794                        qualifier = *fmt++;
 795                        if (unlikely(qualifier == *fmt)) {
 796                                if (qualifier == 'h') {
 797                                        qualifier = 'H';
 798                                        fmt++;
 799                                } else if (qualifier == 'l') {
 800                                        qualifier = 'L';
 801                                        fmt++;
 802                                }
 803                        }
 804                }
 805                base = 10;
 806                is_sign = 0;
 807
 808                if (!*fmt || !*str)
 809                        break;
 810
 811                switch(*fmt++) {
 812                case 'c':
 813                {
 814                        char *s = (char *) va_arg(args,char*);
 815                        if (field_width == -1)
 816                                field_width = 1;
 817                        do {
 818                                *s++ = *str++;
 819                        } while (--field_width > 0 && *str);
 820                        num++;
 821                }
 822                continue;
 823                case 's':
 824                {
 825                        char *s = (char *) va_arg(args, char *);
 826                        if(field_width == -1)
 827                                field_width = INT_MAX;
 828                        /* first, skip leading white space in buffer */
 829                        while (isspace(*str))
 830                                str++;
 831
 832                        /* now copy until next white space */
 833                        while (*str && !isspace(*str) && field_width--) {
 834                                *s++ = *str++;
 835                        }
 836                        *s = '\0';
 837                        num++;
 838                }
 839                continue;
 840                case 'n':
 841                        /* return number of characters read so far */
 842                {
 843                        int *i = (int *)va_arg(args,int*);
 844                        *i = str - buf;
 845                }
 846                continue;
 847                case 'o':
 848                        base = 8;
 849                        break;
 850                case 'x':
 851                case 'X':
 852                        base = 16;
 853                        break;
 854                case 'i':
 855                        base = 0;
 856                case 'd':
 857                        is_sign = 1;
 858                case 'u':
 859                        break;
 860                case '%':
 861                        /* looking for '%' in str */
 862                        if (*str++ != '%') 
 863                                return num;
 864                        continue;
 865                default:
 866                        /* invalid format; stop here */
 867                        return num;
 868                }
 869
 870                /* have some sort of integer conversion.
 871                 * first, skip white space in buffer.
 872                 */
 873                while (isspace(*str))
 874                        str++;
 875
 876                digit = *str;
 877                if (is_sign && digit == '-')
 878                        digit = *(str + 1);
 879
 880                if (!digit
 881                    || (base == 16 && !isxdigit(digit))
 882                    || (base == 10 && !isdigit(digit))
 883                    || (base == 8 && (!isdigit(digit) || digit > '7'))
 884                    || (base == 0 && !isdigit(digit)))
 885                                break;
 886
 887                switch(qualifier) {
 888                case 'H':       /* that's 'hh' in format */
 889                        if (is_sign) {
 890                                signed char *s = (signed char *) va_arg(args,signed char *);
 891                                *s = (signed char) simple_strtol(str,&next,base);
 892                        } else {
 893                                unsigned char *s = (unsigned char *) va_arg(args, unsigned char *);
 894                                *s = (unsigned char) simple_strtoul(str, &next, base);
 895                        }
 896                        break;
 897                case 'h':
 898                        if (is_sign) {
 899                                short *s = (short *) va_arg(args,short *);
 900                                *s = (short) simple_strtol(str,&next,base);
 901                        } else {
 902                                unsigned short *s = (unsigned short *) va_arg(args, unsigned short *);
 903                                *s = (unsigned short) simple_strtoul(str, &next, base);
 904                        }
 905                        break;
 906                case 'l':
 907                        if (is_sign) {
 908                                long *l = (long *) va_arg(args,long *);
 909                                *l = simple_strtol(str,&next,base);
 910                        } else {
 911                                unsigned long *l = (unsigned long*) va_arg(args,unsigned long*);
 912                                *l = simple_strtoul(str,&next,base);
 913                        }
 914                        break;
 915                case 'L':
 916                        if (is_sign) {
 917                                long long *l = (long long*) va_arg(args,long long *);
 918                                *l = simple_strtoll(str,&next,base);
 919                        } else {
 920                                unsigned long long *l = (unsigned long long*) va_arg(args,unsigned long long*);
 921                                *l = simple_strtoull(str,&next,base);
 922                        }
 923                        break;
 924                case 'Z':
 925                case 'z':
 926                {
 927                        size_t *s = (size_t*) va_arg(args,size_t*);
 928                        *s = (size_t) simple_strtoul(str,&next,base);
 929                }
 930                break;
 931                default:
 932                        if (is_sign) {
 933                                int *i = (int *) va_arg(args, int*);
 934                                *i = (int) simple_strtol(str,&next,base);
 935                        } else {
 936                                unsigned int *i = (unsigned int*) va_arg(args, unsigned int*);
 937                                *i = (unsigned int) simple_strtoul(str,&next,base);
 938                        }
 939                        break;
 940                }
 941                num++;
 942
 943                if (!next)
 944                        break;
 945                str = next;
 946        }
 947
 948        /*
 949         * Now we've come all the way through so either the input string or the
 950         * format ended. In the former case, there can be a %n at the current
 951         * position in the format that needs to be filled.
 952         */
 953        if (*fmt == '%' && *(fmt + 1) == 'n') {
 954                int *p = (int *)va_arg(args, int *);
 955                *p = str - buf;
 956        }
 957
 958        return num;
 959}
 960
 961EXPORT_SYMBOL(vsscanf);
 962
 963/**
 964 * sscanf - Unformat a buffer into a list of arguments
 965 * @buf:        input buffer
 966 * @fmt:        formatting of buffer
 967 * @...:        resulting arguments
 968 */
 969int sscanf(const char * buf, const char * fmt, ...)
 970{
 971        va_list args;
 972        int i;
 973
 974        va_start(args,fmt);
 975        i = vsscanf(buf,fmt,args);
 976        va_end(args);
 977        return i;
 978}
 979
 980EXPORT_SYMBOL(sscanf);
 981