snprintf.c
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上传日期:2007-10-30
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- /*
- * Copyright Patrick Powell 1995
- * This code is based on code written by Patrick Powell (papowell@astart.com)
- * It may be used for any purpose as long as this notice remains intact
- * on all source code distributions
- */
- /**************************************************************
- * Original:
- * Patrick Powell Tue Apr 11 09:48:21 PDT 1995
- * A bombproof version of doprnt (dopr) included.
- * Sigh. This sort of thing is always nasty do deal with. Note that
- * the version here does not include floating point...
- *
- * snprintf() is used instead of sprintf() as it does limit checks
- * for string length. This covers a nasty loophole.
- *
- * The other functions are there to prevent NULL pointers from
- * causing nast effects.
- *
- * More Recently:
- * Brandon Long <blong@fiction.net> 9/15/96 for mutt 0.43
- * This was ugly. It is still ugly. I opted out of floating point
- * numbers, but the formatter understands just about everything
- * from the normal C string format, at least as far as I can tell from
- * the Solaris 2.5 printf(3S) man page.
- *
- * Brandon Long <blong@fiction.net> 10/22/97 for mutt 0.87.1
- * Ok, added some minimal floating point support, which means this
- * probably requires libm on most operating systems. Don't yet
- * support the exponent (e,E) and sigfig (g,G). Also, fmtint()
- * was pretty badly broken, it just wasn't being exercised in ways
- * which showed it, so that's been fixed. Also, formated the code
- * to mutt conventions, and removed dead code left over from the
- * original. Also, there is now a builtin-test, just compile with:
- * gcc -DTEST_SNPRINTF -o snprintf snprintf.c -lm
- * and run snprintf for results.
- *
- * Thomas Roessler <roessler@guug.de> 01/27/98 for mutt 0.89i
- * The PGP code was using unsigned hexadecimal formats.
- * Unfortunately, unsigned formats simply didn't work.
- *
- * Michael Elkins <me@cs.hmc.edu> 03/05/98 for mutt 0.90.8
- * The original code assumed that both snprintf() and vsnprintf() were
- * missing. Some systems only have snprintf() but not vsnprintf(), so
- * the code is now broken down under HAVE_SNPRINTF and HAVE_VSNPRINTF.
- *
- * Andrew Tridgell (tridge@samba.org) Oct 1998
- * fixed handling of %.0f
- * added test for HAVE_LONG_DOUBLE
- *
- **************************************************************/
- #include <net-snmp/net-snmp-config.h>
- #if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)
- #if HAVE_STRING_H
- #include <string.h>
- #else
- #include <strings.h>
- #endif
- #include <ctype.h>
- #include <sys/types.h>
- #if HAVE_STDARG_H
- # include <stdarg.h>
- # define HAVE_STDARGS /* let's hope that works everywhere (mj) */
- # define VA_LOCAL_DECL va_list ap
- # define VA_START(f) va_start(ap, f)
- # define VA_SHIFT(v,t) ; /* no-op for ANSI */
- # define VA_END va_end(ap)
- #elif HAVE_VARARGS_H
- # include <varargs.h>
- # undef HAVE_STDARGS
- # define VA_LOCAL_DECL va_list ap
- # define VA_START(f) va_start(ap) /* f is ignored! */
- # define VA_SHIFT(v,t) v = va_arg(ap,t)
- # define VA_END va_end(ap)
- #else
- /*
- * XX ** NO VARARGS ** XX
- */
- #endif
- #ifdef HAVE_LONG_DOUBLE
- #define LDOUBLE long double
- #else
- #define LDOUBLE double
- #endif
- int snprintf(char *str, size_t count, const char *fmt, ...);
- int vsnprintf(char *str, size_t count, const char *fmt,
- va_list arg);
- static void dopr(char *buffer, size_t maxlen, const char *format,
- va_list args);
- static void fmtstr(char *buffer, size_t * currlen, size_t maxlen,
- char *value, int flags, int min, int max);
- static void fmtint(char *buffer, size_t * currlen, size_t maxlen,
- long value, int base, int min, int max, int flags);
- static void fmtfp(char *buffer, size_t * currlen, size_t maxlen,
- LDOUBLE fvalue, int min, int max, int flags);
- static void dopr_outch(char *buffer, size_t * currlen, size_t maxlen,
- char c);
- /*
- * dopr(): poor man's version of doprintf
- */
- /*
- * format read states
- */
- #define DP_S_DEFAULT 0
- #define DP_S_FLAGS 1
- #define DP_S_MIN 2
- #define DP_S_DOT 3
- #define DP_S_MAX 4
- #define DP_S_MOD 5
- #define DP_S_CONV 6
- #define DP_S_DONE 7
- /*
- * format flags - Bits
- */
- #define DP_F_MINUS (1 << 0)
- #define DP_F_PLUS (1 << 1)
- #define DP_F_SPACE (1 << 2)
- #define DP_F_NUM (1 << 3)
- #define DP_F_ZERO (1 << 4)
- #define DP_F_UP (1 << 5)
- #define DP_F_UNSIGNED (1 << 6)
- /*
- * Conversion Flags
- */
- #define DP_C_SHORT 1
- #define DP_C_LONG 2
- #define DP_C_LDOUBLE 3
- #define char_to_int(p) (p - '0')
- #define MAX(p,q) ((p >= q) ? p : q)
- static void
- dopr(char *buffer, size_t maxlen, const char *format, va_list args)
- {
- char ch;
- long value;
- LDOUBLE fvalue;
- char *strvalue;
- int min;
- int max;
- int state;
- int flags;
- int cflags;
- size_t currlen;
- state = DP_S_DEFAULT;
- currlen = flags = cflags = min = 0;
- max = -1;
- ch = *format++;
- while (state != DP_S_DONE) {
- if ((ch == ' ') || (currlen >= maxlen))
- state = DP_S_DONE;
- switch (state) {
- case DP_S_DEFAULT:
- if (ch == '%')
- state = DP_S_FLAGS;
- else
- dopr_outch(buffer, &currlen, maxlen, ch);
- ch = *format++;
- break;
- case DP_S_FLAGS:
- switch (ch) {
- case '-':
- flags |= DP_F_MINUS;
- ch = *format++;
- break;
- case '+':
- flags |= DP_F_PLUS;
- ch = *format++;
- break;
- case ' ':
- flags |= DP_F_SPACE;
- ch = *format++;
- break;
- case '#':
- flags |= DP_F_NUM;
- ch = *format++;
- break;
- case '0':
- flags |= DP_F_ZERO;
- ch = *format++;
- break;
- default:
- state = DP_S_MIN;
- break;
- }
- break;
- case DP_S_MIN:
- if (isdigit(ch)) {
- min = 10 * min + char_to_int(ch);
- ch = *format++;
- } else if (ch == '*') {
- min = va_arg(args, int);
- ch = *format++;
- state = DP_S_DOT;
- } else
- state = DP_S_DOT;
- break;
- case DP_S_DOT:
- if (ch == '.') {
- state = DP_S_MAX;
- ch = *format++;
- } else
- state = DP_S_MOD;
- break;
- case DP_S_MAX:
- if (isdigit(ch)) {
- if (max < 0)
- max = 0;
- max = 10 * max + char_to_int(ch);
- ch = *format++;
- } else if (ch == '*') {
- max = va_arg(args, int);
- ch = *format++;
- state = DP_S_MOD;
- } else
- state = DP_S_MOD;
- break;
- case DP_S_MOD:
- /*
- * Currently, we don't support Long Long, bummer
- */
- switch (ch) {
- case 'h':
- cflags = DP_C_SHORT;
- ch = *format++;
- break;
- case 'l':
- cflags = DP_C_LONG;
- ch = *format++;
- break;
- case 'L':
- cflags = DP_C_LDOUBLE;
- ch = *format++;
- break;
- default:
- break;
- }
- state = DP_S_CONV;
- break;
- case DP_S_CONV:
- switch (ch) {
- case 'd':
- case 'i':
- if (cflags == DP_C_SHORT)
- value = va_arg(args, short int);
- else if (cflags == DP_C_LONG)
- value = va_arg(args, long int);
- else
- value = va_arg(args, int);
- fmtint(buffer, &currlen, maxlen, value, 10, min, max,
- flags);
- break;
- case 'o':
- flags |= DP_F_UNSIGNED;
- if (cflags == DP_C_SHORT)
- value = va_arg(args, unsigned short int);
- else if (cflags == DP_C_LONG)
- value = va_arg(args, unsigned long int);
- else
- value = va_arg(args, unsigned int);
- fmtint(buffer, &currlen, maxlen, value, 8, min, max,
- flags);
- break;
- case 'u':
- flags |= DP_F_UNSIGNED;
- if (cflags == DP_C_SHORT)
- value = va_arg(args, unsigned short int);
- else if (cflags == DP_C_LONG)
- value = va_arg(args, unsigned long int);
- else
- value = va_arg(args, unsigned int);
- fmtint(buffer, &currlen, maxlen, value, 10, min, max,
- flags);
- break;
- case 'X':
- flags |= DP_F_UP;
- case 'x':
- flags |= DP_F_UNSIGNED;
- if (cflags == DP_C_SHORT)
- value = va_arg(args, unsigned short int);
- else if (cflags == DP_C_LONG)
- value = va_arg(args, unsigned long int);
- else
- value = va_arg(args, unsigned int);
- fmtint(buffer, &currlen, maxlen, value, 16, min, max,
- flags);
- break;
- case 'f':
- if (cflags == DP_C_LDOUBLE)
- fvalue = va_arg(args, LDOUBLE);
- else
- fvalue = va_arg(args, double);
- /*
- * um, floating point?
- */
- fmtfp(buffer, &currlen, maxlen, fvalue, min, max, flags);
- break;
- case 'E':
- flags |= DP_F_UP;
- case 'e':
- if (cflags == DP_C_LDOUBLE)
- fvalue = va_arg(args, LDOUBLE);
- else
- fvalue = va_arg(args, double);
- break;
- case 'G':
- flags |= DP_F_UP;
- case 'g':
- if (cflags == DP_C_LDOUBLE)
- fvalue = va_arg(args, LDOUBLE);
- else
- fvalue = va_arg(args, double);
- break;
- case 'c':
- dopr_outch(buffer, &currlen, maxlen, va_arg(args, int));
- break;
- case 's':
- strvalue = va_arg(args, char *);
- if (max < 0)
- max = maxlen; /* ie, no max */
- fmtstr(buffer, &currlen, maxlen, strvalue, flags, min,
- max);
- break;
- case 'p':
- strvalue = (char *) va_arg(args, void *);
- fmtint(buffer, &currlen, maxlen, (long) strvalue, 16, min,
- max, flags);
- break;
- case 'n':
- if (cflags == DP_C_SHORT) {
- short int *num;
- num = va_arg(args, short int *);
- *num = currlen;
- } else if (cflags == DP_C_LONG) {
- long int *num;
- num = va_arg(args, long int *);
- *num = currlen;
- } else {
- int *num;
- num = va_arg(args, int *);
- *num = currlen;
- }
- break;
- case '%':
- dopr_outch(buffer, &currlen, maxlen, ch);
- break;
- case 'w':
- /*
- * not supported yet, treat as next char
- */
- ch = *format++;
- break;
- default:
- /*
- * Unknown, skip
- */
- break;
- }
- ch = *format++;
- state = DP_S_DEFAULT;
- flags = cflags = min = 0;
- max = -1;
- break;
- case DP_S_DONE:
- break;
- default:
- /*
- * hmm?
- */
- break; /* some picky compilers need this */
- }
- }
- if (currlen < maxlen - 1)
- buffer[currlen] = ' ';
- else
- buffer[maxlen - 1] = ' ';
- }
- static void
- fmtstr(char *buffer, size_t * currlen, size_t maxlen,
- char *value, int flags, int min, int max)
- {
- int padlen, strln; /* amount to pad */
- int cnt = 0;
- if (value == 0) {
- value = "<NULL>";
- }
- for (strln = 0; value[strln]; ++strln); /* strlen */
- padlen = min - strln;
- if (padlen < 0)
- padlen = 0;
- if (flags & DP_F_MINUS)
- padlen = -padlen; /* Left Justify */
- while ((padlen > 0) && (cnt < max)) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- --padlen;
- ++cnt;
- }
- while (*value && (cnt < max)) {
- dopr_outch(buffer, currlen, maxlen, *value++);
- ++cnt;
- }
- while ((padlen < 0) && (cnt < max)) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- ++padlen;
- ++cnt;
- }
- }
- /*
- * Have to handle DP_F_NUM (ie 0x and 0 alternates)
- */
- static void
- fmtint(char *buffer, size_t * currlen, size_t maxlen,
- long value, int base, int min, int max, int flags)
- {
- int signvalue = 0;
- unsigned long uvalue;
- char convert[20];
- int place = 0;
- int spadlen = 0; /* amount to space pad */
- int zpadlen = 0; /* amount to zero pad */
- int caps = 0;
- if (max < 0)
- max = 0;
- uvalue = value;
- if (!(flags & DP_F_UNSIGNED)) {
- if (value < 0) {
- signvalue = '-';
- uvalue = -value;
- } else if (flags & DP_F_PLUS) /* Do a sign (+/i) */
- signvalue = '+';
- else if (flags & DP_F_SPACE)
- signvalue = ' ';
- }
- if (flags & DP_F_UP)
- caps = 1; /* Should characters be upper case? */
- do {
- convert[place++] = (caps ? "0123456789ABCDEF" : "0123456789abcdef")
- [uvalue % (unsigned) base];
- uvalue = (uvalue / (unsigned) base);
- } while (uvalue && (place < 20));
- if (place == 20)
- place--;
- convert[place] = 0;
- zpadlen = max - place;
- spadlen = min - MAX(max, place) - (signvalue ? 1 : 0);
- if (zpadlen < 0)
- zpadlen = 0;
- if (spadlen < 0)
- spadlen = 0;
- if (flags & DP_F_ZERO) {
- zpadlen = MAX(zpadlen, spadlen);
- spadlen = 0;
- }
- if (flags & DP_F_MINUS)
- spadlen = -spadlen; /* Left Justifty */
- #ifdef DEBUG_SNPRINTF
- dprint(1,
- (debugfile, "zpad: %d, spad: %d, min: %d, max: %d, place: %dn",
- zpadlen, spadlen, min, max, place));
- #endif
- /*
- * Spaces
- */
- while (spadlen > 0) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- --spadlen;
- }
- /*
- * Sign
- */
- if (signvalue)
- dopr_outch(buffer, currlen, maxlen, signvalue);
- /*
- * Zeros
- */
- if (zpadlen > 0) {
- while (zpadlen > 0) {
- dopr_outch(buffer, currlen, maxlen, '0');
- --zpadlen;
- }
- }
- /*
- * Digits
- */
- while (place > 0)
- dopr_outch(buffer, currlen, maxlen, convert[--place]);
- /*
- * Left Justified spaces
- */
- while (spadlen < 0) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- ++spadlen;
- }
- }
- static LDOUBLE
- abs_val(LDOUBLE value)
- {
- LDOUBLE result = value;
- if (value < 0)
- result = -value;
- return result;
- }
- static LDOUBLE
- pow10(int exp)
- {
- LDOUBLE result = 1;
- while (exp) {
- result *= 10;
- exp--;
- }
- return result;
- }
- static long
- round(LDOUBLE value)
- {
- long intpart;
- intpart = value;
- value = value - intpart;
- if (value >= 0.5)
- intpart++;
- return intpart;
- }
- static void
- fmtfp(char *buffer, size_t * currlen, size_t maxlen,
- LDOUBLE fvalue, int min, int max, int flags)
- {
- int signvalue = 0;
- LDOUBLE ufvalue;
- char iconvert[20];
- char fconvert[20];
- int iplace = 0;
- int fplace = 0;
- int padlen = 0; /* amount to pad */
- int zpadlen = 0;
- int caps = 0;
- long intpart;
- long fracpart;
- /*
- * AIX manpage says the default is 0, but Solaris says the default
- * is 6, and sprintf on AIX defaults to 6
- */
- if (max < 0)
- max = 6;
- ufvalue = abs_val(fvalue);
- if (fvalue < 0)
- signvalue = '-';
- else if (flags & DP_F_PLUS) /* Do a sign (+/i) */
- signvalue = '+';
- else if (flags & DP_F_SPACE)
- signvalue = ' ';
- #if 0
- if (flags & DP_F_UP)
- caps = 1; /* Should characters be upper case? */
- #endif
- intpart = ufvalue;
- /*
- * Sorry, we only support 9 digits past the decimal because of our
- * conversion method
- */
- if (max > 9)
- max = 9;
- /*
- * We "cheat" by converting the fractional part to integer by
- * * multiplying by a factor of 10
- */
- fracpart = round((pow10(max)) * (ufvalue - intpart));
- if (fracpart >= pow10(max)) {
- intpart++;
- fracpart -= pow10(max);
- }
- #ifdef DEBUG_SNPRINTF
- dprint(1,
- (debugfile, "fmtfp: %f =? %d.%dn", fvalue, intpart, fracpart));
- #endif
- /*
- * Convert integer part
- */
- do {
- iconvert[iplace++] =
- (caps ? "0123456789ABCDEF" : "0123456789abcdef")[intpart % 10];
- intpart = (intpart / 10);
- } while (intpart && (iplace < 20));
- if (iplace == 20)
- iplace--;
- iconvert[iplace] = 0;
- /*
- * Convert fractional part
- */
- do {
- fconvert[fplace++] =
- (caps ? "0123456789ABCDEF" : "0123456789abcdef")[fracpart %
- 10];
- fracpart = (fracpart / 10);
- } while (fracpart && (fplace < 20));
- if (fplace == 20)
- fplace--;
- fconvert[fplace] = 0;
- /*
- * -1 for decimal point, another -1 if we are printing a sign
- */
- padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0);
- zpadlen = max - fplace;
- if (zpadlen < 0)
- zpadlen = 0;
- if (padlen < 0)
- padlen = 0;
- if (flags & DP_F_MINUS)
- padlen = -padlen; /* Left Justifty */
- if ((flags & DP_F_ZERO) && (padlen > 0)) {
- if (signvalue) {
- dopr_outch(buffer, currlen, maxlen, signvalue);
- --padlen;
- signvalue = 0;
- }
- while (padlen > 0) {
- dopr_outch(buffer, currlen, maxlen, '0');
- --padlen;
- }
- }
- while (padlen > 0) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- --padlen;
- }
- if (signvalue)
- dopr_outch(buffer, currlen, maxlen, signvalue);
- while (iplace > 0)
- dopr_outch(buffer, currlen, maxlen, iconvert[--iplace]);
- /*
- * Decimal point. This should probably use locale to find the correct
- * char to print out.
- */
- if (max > 0) {
- dopr_outch(buffer, currlen, maxlen, '.');
- while (fplace > 0)
- dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);
- }
- while (zpadlen > 0) {
- dopr_outch(buffer, currlen, maxlen, '0');
- --zpadlen;
- }
- while (padlen < 0) {
- dopr_outch(buffer, currlen, maxlen, ' ');
- ++padlen;
- }
- }
- static void
- dopr_outch(char *buffer, size_t * currlen, size_t maxlen, char c)
- {
- if (*currlen < maxlen)
- buffer[(*currlen)++] = c;
- }
- #ifndef HAVE_VSNPRINTF
- int
- vsnprintf(char *str, size_t count, const char *fmt, va_list args)
- {
- str[0] = 0;
- dopr(str, count, fmt, args);
- return (strlen(str));
- }
- #endif /* !HAVE_VSNPRINTF */
- #ifndef HAVE_SNPRINTF
- /*
- * VARARGS3
- */
- #ifdef HAVE_STDARGS
- int
- snprintf(char *str, size_t count, const char *fmt, ...)
- #else
- int
- snprintf(va_alist)
- va_dcl
- #endif
- {
- #ifndef HAVE_STDARGS
- char *str;
- size_t count;
- char *fmt;
- #endif
- VA_LOCAL_DECL;
- VA_START(fmt);
- VA_SHIFT(str, char *);
- VA_SHIFT(count, size_t);
- VA_SHIFT(fmt, char *);
- (void) vsnprintf(str, count, fmt, ap);
- VA_END;
- return (strlen(str));
- }
- #endif /* !HAVE_SNPRINTF */
- #ifdef TEST_SNPRINTF
- #ifndef LONG_STRING
- #define LONG_STRING 1024
- #endif
- int
- main(void)
- {
- char buf1[LONG_STRING];
- char buf2[LONG_STRING];
- char *fp_fmt[] = {
- "%-1.5f",
- "%1.5f",
- "%123.9f",
- "%10.5f",
- "% 10.5f",
- "%+22.9f",
- "%+4.9f",
- "%01.3f",
- "%4f",
- "%3.1f",
- "%3.2f",
- "%.0f",
- "%.1f",
- NULL
- };
- double fp_nums[] =
- { -1.5, 134.21, 91340.2, 341.1234, 0203.9, 0.96, 0.996,
- 0.9996, 1.996, 4.136, 0
- };
- char *int_fmt[] = {
- "%-1.5d",
- "%1.5d",
- "%123.9d",
- "%5.5d",
- "%10.5d",
- "% 10.5d",
- "%+22.33d",
- "%01.3d",
- "%4d",
- NULL
- };
- long int_nums[] = { -1, 134, 91340, 341, 0203, 0 };
- int x, y;
- int fail = 0;
- int num = 0;
- printf("Testing snprintf format codes against system sprintf...n");
- for (x = 0; fp_fmt[x] != NULL; x++)
- for (y = 0; fp_nums[y] != 0; y++) {
- snprintf(buf1, sizeof(buf1), fp_fmt[x], fp_nums[y]);
- sprintf(buf2, fp_fmt[x], fp_nums[y]);
- if (strcmp(buf1, buf2)) {
- printf
- ("snprintf doesn't match Format: %sntsnprintf = %sntsprintf = %sn",
- fp_fmt[x], buf1, buf2);
- fail++;
- }
- num++;
- }
- for (x = 0; int_fmt[x] != NULL; x++)
- for (y = 0; int_nums[y] != 0; y++) {
- snprintf(buf1, sizeof(buf1), int_fmt[x], int_nums[y]);
- sprintf(buf2, int_fmt[x], int_nums[y]);
- if (strcmp(buf1, buf2)) {
- printf
- ("snprintf doesn't match Format: %sntsnprintf = %sntsprintf = %sn",
- int_fmt[x], buf1, buf2);
- fail++;
- }
- num++;
- }
- printf("%d tests failed out of %d.n", fail, num);
- }
- #endif /* SNPRINTF_TEST */
- #endif /* !HAVE_SNPRINTF */