vfscanf.c
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上传日期:2007-04-14
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文件大小:18k
- /*-
- * Copyright (c) 1990 The Regents of the University of California.
- * Copyright (c) 1993, 1994 Chris Provenzano.
- * All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Chris Torek.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #if defined(LIBC_SCCS) && !defined(lint)
- /*static char *sccsid = "from: @(#)vfscanf.c 5.7 (Berkeley) 12/14/92";*/
- static char *rcsid = "$Id$";
- #endif /* LIBC_SCCS and not lint */
- #include <stdio.h>
- #include <stdlib.h>
- #include <ctype.h>
- #if __STDC__
- #include <stdarg.h>
- #else
- #include <varargs.h>
- #endif
- #include "local.h"
- #define FLOATING_POINT
- #include "floatio.h"
- #define BUF 513 /* Maximum length of numeric string. */
- /*
- * Flags used during conversion.
- */
- #define LONG 0x01 /* l: long or double */
- #define LONGDBL 0x02 /* L: long double; unimplemented */
- #define SHORT 0x04 /* h: short */
- #define SUPPRESS 0x08 /* suppress assignment */
- #define POINTER 0x10 /* weird %p pointer (`fake hex') */
- #define NOSKIP 0x20 /* do not skip blanks */
- /*
- * The following are used in numeric conversions only:
- * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
- * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
- */
- #define SIGNOK 0x40 /* +/- is (still) legal */
- #define NDIGITS 0x80 /* no digits detected */
- #define DPTOK 0x100 /* (float) decimal point is still legal */
- #define EXPOK 0x200 /* (float) exponent (e+3, etc) still legal */
- #define PFXOK 0x100 /* 0x prefix is (still) legal */
- #define NZDIGITS 0x200 /* no zero digits detected */
- /*
- * Conversion types.
- */
- #define CT_CHAR 0 /* %c conversion */
- #define CT_CCL 1 /* %[...] conversion */
- #define CT_STRING 2 /* %s conversion */
- #define CT_INT 3 /* integer, i.e., strtol or strtoul */
- #define CT_FLOAT 4 /* floating, i.e., strtod */
- #define u_char unsigned char
- #define u_long unsigned long
- static u_char *__sccl();
- /*
- * vfscanf
- */
- __svfscanf(fp, fmt0, ap)
- register FILE *fp;
- char const *fmt0;
- pthread_va_list ap;
- {
- register u_char *fmt = (u_char *)fmt0;
- register int c; /* character from format, or conversion */
- register size_t width; /* field width, or 0 */
- register char *p; /* points into all kinds of strings */
- register int n; /* handy integer */
- register int flags; /* flags as defined above */
- register char *p0; /* saves original value of p when necessary */
- int nassigned; /* number of fields assigned */
- int nread; /* number of characters consumed from fp */
- int base; /* base argument to strtol/strtoul */
- u_long (*ccfn)(); /* conversion function (strtol/strtoul) */
- char ccltab[256]; /* character class table for %[...] */
- char buf[BUF]; /* buffer for numeric conversions */
- /* `basefix' is used to avoid `if' tests in the integer scanner */
- static short basefix[17] =
- { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
- nassigned = 0;
- nread = 0;
- base = 0; /* XXX just to keep gcc happy */
- ccfn = NULL; /* XXX just to keep gcc happy */
- for (;;) {
- c = *fmt++;
- if (c == 0)
- return (nassigned);
- if (isspace(c)) {
- for (;;) {
- if (fp->_r <= 0 && __srefill(fp))
- return (nassigned);
- if (!isspace(*fp->_p))
- break;
- nread++, fp->_r--, fp->_p++;
- }
- continue;
- }
- if (c != '%')
- goto literal;
- width = 0;
- flags = 0;
- /*
- * switch on the format. continue if done;
- * break once format type is derived.
- */
- again: c = *fmt++;
- switch (c) {
- case '%':
- literal:
- if (fp->_r <= 0 && __srefill(fp))
- goto input_failure;
- if (*fp->_p != c)
- goto match_failure;
- fp->_r--, fp->_p++;
- nread++;
- continue;
- case '*':
- flags |= SUPPRESS;
- goto again;
- case 'l':
- flags |= LONG;
- goto again;
- case 'L':
- flags |= LONGDBL;
- goto again;
- case 'h':
- flags |= SHORT;
- goto again;
- case '0': case '1': case '2': case '3': case '4':
- case '5': case '6': case '7': case '8': case '9':
- width = width * 10 + c - '0';
- goto again;
- /*
- * Conversions.
- * Those marked `compat' are for 4.[123]BSD compatibility.
- *
- * (According to ANSI, E and X formats are supposed
- * to the same as e and x. Sorry about that.)
- */
- case 'D': /* compat */
- flags |= LONG;
- /* FALLTHROUGH */
- case 'd':
- c = CT_INT;
- ccfn = (u_long (*)())strtol;
- base = 10;
- break;
- case 'i':
- c = CT_INT;
- ccfn = (u_long (*)())strtol;
- base = 0;
- break;
- case 'O': /* compat */
- flags |= LONG;
- /* FALLTHROUGH */
- case 'o':
- c = CT_INT;
- ccfn = strtoul;
- base = 8;
- break;
- case 'u':
- c = CT_INT;
- ccfn = strtoul;
- base = 10;
- break;
- case 'X': /* compat XXX */
- flags |= LONG;
- /* FALLTHROUGH */
- case 'x':
- flags |= PFXOK; /* enable 0x prefixing */
- c = CT_INT;
- ccfn = strtoul;
- base = 16;
- break;
- #ifdef FLOATING_POINT
- case 'E': /* compat XXX */
- case 'F': /* compat */
- flags |= LONG;
- /* FALLTHROUGH */
- case 'e': case 'f': case 'g':
- c = CT_FLOAT;
- break;
- #endif
- case 's':
- c = CT_STRING;
- break;
- case '[':
- fmt = __sccl(ccltab, fmt);
- flags |= NOSKIP;
- c = CT_CCL;
- break;
- case 'c':
- flags |= NOSKIP;
- c = CT_CHAR;
- break;
- case 'p': /* pointer format is like hex */
- flags |= POINTER | PFXOK;
- c = CT_INT;
- ccfn = strtoul;
- base = 16;
- break;
- case 'n':
- if (flags & SUPPRESS) /* ??? */
- continue;
- if (flags & SHORT)
- *va_arg(ap, short *) = nread;
- else if (flags & LONG)
- *va_arg(ap, long *) = nread;
- else
- *va_arg(ap, int *) = nread;
- continue;
- /*
- * Disgusting backwards compatibility hacks. XXX
- */
- case ' ': /* compat */
- return (EOF);
- default: /* compat */
- if (isupper(c))
- flags |= LONG;
- c = CT_INT;
- ccfn = (u_long (*)())strtol;
- base = 10;
- break;
- }
- /*
- * We have a conversion that requires input.
- */
- if (fp->_r <= 0 && __srefill(fp))
- goto input_failure;
- /*
- * Consume leading white space, except for formats
- * that suppress this.
- */
- if ((flags & NOSKIP) == 0) {
- while (isspace(*fp->_p)) {
- nread++;
- if (--fp->_r > 0)
- fp->_p++;
- else if (__srefill(fp))
- goto input_failure;
- }
- /*
- * Note that there is at least one character in
- * the buffer, so conversions that do not set NOSKIP
- * ca no longer result in an input failure.
- */
- }
- /*
- * Do the conversion.
- */
- switch (c) {
- case CT_CHAR:
- /* scan arbitrary characters (sets NOSKIP) */
- if (width == 0)
- width = 1;
- if (flags & SUPPRESS) {
- size_t sum = 0;
- for (;;) {
- if ((n = fp->_r) < width) {
- sum += n;
- width -= n;
- fp->_p += n;
- if (__srefill(fp)) {
- if (sum == 0)
- goto input_failure;
- break;
- }
- } else {
- sum += width;
- fp->_r -= width;
- fp->_p += width;
- break;
- }
- }
- nread += sum;
- } else {
- size_t r = fread((void *)va_arg(ap, char *), 1,
- width, fp);
- if (r == 0)
- goto input_failure;
- nread += r;
- nassigned++;
- }
- break;
- case CT_CCL:
- /* scan a (nonempty) character class (sets NOSKIP) */
- if (width == 0)
- width = ~0; /* `infinity' */
- /* take only those things in the class */
- if (flags & SUPPRESS) {
- n = 0;
- while (ccltab[*fp->_p]) {
- n++, fp->_r--, fp->_p++;
- if (--width == 0)
- break;
- if (fp->_r <= 0 && __srefill(fp)) {
- if (n == 0)
- goto input_failure;
- break;
- }
- }
- if (n == 0)
- goto match_failure;
- } else {
- p0 = p = va_arg(ap, char *);
- while (ccltab[*fp->_p]) {
- fp->_r--;
- *p++ = *fp->_p++;
- if (--width == 0)
- break;
- if (fp->_r <= 0 && __srefill(fp)) {
- if (p == p0)
- goto input_failure;
- break;
- }
- }
- n = p - p0;
- if (n == 0)
- goto match_failure;
- *p = 0;
- nassigned++;
- }
- nread += n;
- break;
- case CT_STRING:
- /* like CCL, but zero-length string OK, & no NOSKIP */
- if (width == 0)
- width = ~0;
- if (flags & SUPPRESS) {
- n = 0;
- while (!isspace(*fp->_p)) {
- n++, fp->_r--, fp->_p++;
- if (--width == 0)
- break;
- if (fp->_r <= 0 && __srefill(fp))
- break;
- }
- nread += n;
- } else {
- p0 = p = va_arg(ap, char *);
- while (!isspace(*fp->_p)) {
- fp->_r--;
- *p++ = *fp->_p++;
- if (--width == 0)
- break;
- if (fp->_r <= 0 && __srefill(fp))
- break;
- }
- *p = 0;
- nread += p - p0;
- nassigned++;
- }
- continue;
- case CT_INT:
- /* scan an integer as if by strtol/strtoul */
- #ifdef hardway
- if (width == 0 || width > sizeof(buf) - 1)
- width = sizeof(buf) - 1;
- #else
- /* size_t is unsigned, hence this optimisation */
- if (--width > sizeof(buf) - 2)
- width = sizeof(buf) - 2;
- width++;
- #endif
- flags |= SIGNOK | NDIGITS | NZDIGITS;
- for (p = buf; width; width--) {
- c = *fp->_p;
- /*
- * Switch on the character; `goto ok'
- * if we accept it as a part of number.
- */
- switch (c) {
- /*
- * The digit 0 is always legal, but is
- * special. For %i conversions, if no
- * digits (zero or nonzero) have been
- * scanned (only signs), we will have
- * base==0. In that case, we should set
- * it to 8 and enable 0x prefixing.
- * Also, if we have not scanned zero digits
- * before this, do not turn off prefixing
- * (someone else will turn it off if we
- * have scanned any nonzero digits).
- */
- case '0':
- if (base == 0) {
- base = 8;
- flags |= PFXOK;
- }
- if (flags & NZDIGITS)
- flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
- else
- flags &= ~(SIGNOK|PFXOK|NDIGITS);
- goto ok;
- /* 1 through 7 always legal */
- case '1': case '2': case '3':
- case '4': case '5': case '6': case '7':
- base = basefix[base];
- flags &= ~(SIGNOK | PFXOK | NDIGITS);
- goto ok;
- /* digits 8 and 9 ok iff decimal or hex */
- case '8': case '9':
- base = basefix[base];
- if (base <= 8)
- break; /* not legal here */
- flags &= ~(SIGNOK | PFXOK | NDIGITS);
- goto ok;
- /* letters ok iff hex */
- case 'A': case 'B': case 'C':
- case 'D': case 'E': case 'F':
- case 'a': case 'b': case 'c':
- case 'd': case 'e': case 'f':
- /* no need to fix base here */
- if (base <= 10)
- break; /* not legal here */
- flags &= ~(SIGNOK | PFXOK | NDIGITS);
- goto ok;
- /* sign ok only as first character */
- case '+': case '-':
- if (flags & SIGNOK) {
- flags &= ~SIGNOK;
- goto ok;
- }
- break;
- /* x ok iff flag still set & 2nd char */
- case 'x': case 'X':
- if (flags & PFXOK && p == buf + 1) {
- base = 16; /* if %i */
- flags &= ~PFXOK;
- goto ok;
- }
- break;
- }
- /*
- * If we got here, c is not a legal character
- * for a number. Stop accumulating digits.
- */
- break;
- ok:
- /*
- * c is legal: store it and look at the next.
- */
- *p++ = c;
- if (--fp->_r > 0)
- fp->_p++;
- else if (__srefill(fp))
- break; /* EOF */
- }
- /*
- * If we had only a sign, it is no good; push
- * back the sign. If the number ends in `x',
- * it was [sign] '0' 'x', so push back the x
- * and treat it as [sign] '0'.
- */
- if (flags & NDIGITS) {
- if (p > buf)
- (void) ungetc(*(u_char *)--p, fp);
- goto match_failure;
- }
- c = ((u_char *)p)[-1];
- if (c == 'x' || c == 'X') {
- --p;
- (void) ungetc(c, fp);
- }
- if ((flags & SUPPRESS) == 0) {
- u_long res;
- *p = 0;
- res = (*ccfn)(buf, (char **)NULL, base);
- if (flags & POINTER)
- *va_arg(ap, void **) = (void *)res;
- else if (flags & SHORT)
- *va_arg(ap, short *) = res;
- else if (flags & LONG)
- *va_arg(ap, long *) = res;
- else
- *va_arg(ap, int *) = res;
- nassigned++;
- }
- nread += p - buf;
- break;
- #ifdef FLOATING_POINT
- case CT_FLOAT:
- /* scan a floating point number as if by strtod */
- #ifdef hardway
- if (width == 0 || width > sizeof(buf) - 1)
- width = sizeof(buf) - 1;
- #else
- /* size_t is unsigned, hence this optimisation */
- if (--width > sizeof(buf) - 2)
- width = sizeof(buf) - 2;
- width++;
- #endif
- flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
- for (p = buf; width; width--) {
- c = *fp->_p;
- /*
- * This code mimicks the integer conversion
- * code, but is much simpler.
- */
- switch (c) {
- case '0': case '1': case '2': case '3':
- case '4': case '5': case '6': case '7':
- case '8': case '9':
- flags &= ~(SIGNOK | NDIGITS);
- goto fok;
- case '+': case '-':
- if (flags & SIGNOK) {
- flags &= ~SIGNOK;
- goto fok;
- }
- break;
- case '.':
- if (flags & DPTOK) {
- flags &= ~(SIGNOK | DPTOK);
- goto fok;
- }
- break;
- case 'e': case 'E':
- /* no exponent without some digits */
- if ((flags&(NDIGITS|EXPOK)) == EXPOK) {
- flags =
- (flags & ~(EXPOK|DPTOK)) |
- SIGNOK | NDIGITS;
- goto fok;
- }
- break;
- }
- break;
- fok:
- *p++ = c;
- if (--fp->_r > 0)
- fp->_p++;
- else if (__srefill(fp))
- break; /* EOF */
- }
- /*
- * If no digits, might be missing exponent digits
- * (just give back the exponent) or might be missing
- * regular digits, but had sign and/or decimal point.
- */
- if (flags & NDIGITS) {
- if (flags & EXPOK) {
- /* no digits at all */
- while (p > buf)
- ungetc(*(u_char *)--p, fp);
- goto match_failure;
- }
- /* just a bad exponent (e and maybe sign) */
- c = *(u_char *)--p;
- if (c != 'e' && c != 'E') {
- (void) ungetc(c, fp);/* sign */
- c = *(u_char *)--p;
- }
- (void) ungetc(c, fp);
- }
- if ((flags & SUPPRESS) == 0) {
- double res;
- *p = 0;
- res = strtod(buf, (char **) NULL);
- if (flags & LONG)
- *va_arg(ap, double *) = res;
- else
- *va_arg(ap, float *) = res;
- nassigned++;
- }
- nread += p - buf;
- break;
- #endif /* FLOATING_POINT */
- }
- }
- input_failure:
- return (nassigned ? nassigned : -1);
- match_failure:
- return (nassigned);
- }
- /*
- * Fill in the given table from the scanset at the given format
- * (just after `['). Return a pointer to the character past the
- * closing `]'. The table has a 1 wherever characters should be
- * considered part of the scanset.
- */
- static u_char *
- __sccl(tab, fmt)
- register char *tab;
- register u_char *fmt;
- {
- register int c, n, v;
- /* first `clear' the whole table */
- c = *fmt++; /* first char hat => negated scanset */
- if (c == '^') {
- v = 1; /* default => accept */
- c = *fmt++; /* get new first char */
- } else
- v = 0; /* default => reject */
- /* should probably use memset here */
- for (n = 0; n < 256; n++)
- tab[n] = v;
- if (c == 0)
- return (fmt - 1);/* format ended before closing ] */
- /*
- * Now set the entries corresponding to the actual scanset
- * to the opposite of the above.
- *
- * The first character may be ']' (or '-') without being special;
- * the last character may be '-'.
- */
- v = 1 - v;
- for (;;) {
- tab[c] = v; /* take character c */
- doswitch:
- n = *fmt++; /* and examine the next */
- switch (n) {
- case 0: /* format ended too soon */
- return (fmt - 1);
- case '-':
- /*
- * A scanset of the form
- * [01+-]
- * is defined as `the digit 0, the digit 1,
- * the character +, the character -', but
- * the effect of a scanset such as
- * [a-zA-Z0-9]
- * is implementation defined. The V7 Unix
- * scanf treats `a-z' as `the letters a through
- * z', but treats `a-a' as `the letter a, the
- * character -, and the letter a'.
- *
- * For compatibility, the `-' is not considerd
- * to define a range if the character following
- * it is either a close bracket (required by ANSI)
- * or is not numerically greater than the character
- * we just stored in the table (c).
- */
- n = *fmt;
- if (n == ']' || n < c) {
- c = '-';
- break; /* resume the for(;;) */
- }
- fmt++;
- do { /* fill in the range */
- tab[++c] = v;
- } while (c < n);
- #if 1 /* XXX another disgusting compatibility hack */
- /*
- * Alas, the V7 Unix scanf also treats formats
- * such as [a-c-e] as `the letters a through e'.
- * This too is permitted by the standard....
- */
- goto doswitch;
- #else
- c = *fmt++;
- if (c == 0)
- return (fmt - 1);
- if (c == ']')
- return (fmt);
- #endif
- break;
- case ']': /* end of scanset */
- return (fmt);
- default: /* just another character */
- c = n;
- break;
- }
- }
- /* NOTREACHED */
- }