diff options
Diffstat (limited to 'lib/strtol.c')
-rw-r--r-- | lib/strtol.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/lib/strtol.c b/lib/strtol.c new file mode 100644 index 00000000..08ef0a47 --- /dev/null +++ b/lib/strtol.c @@ -0,0 +1,186 @@ +/* Copyright (C) 1991, 1992 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <ctype.h> +#include <errno.h> + +#if HAVE_LIMITS_H +#include <limits.h> +#endif + +#ifndef ULONG_MAX +#define ULONG_MAX ((unsigned long) ~(unsigned long) 0) +#endif + +#ifndef LONG_MAX +#define LONG_MAX (~(1 << (sizeof (long) * 8 - 1))) +#endif + +#ifndef LONG_MIN +#define LONG_MIN (-LONG_MAX - 1) +#endif + +#if STDC_HEADERS +#include <stddef.h> +#include <stdlib.h> +#else +#define NULL 0 +extern int errno; +#endif + +#ifndef UNSIGNED +#define UNSIGNED 0 +#endif + +/* Convert NPTR to an `unsigned long int' or `long int' in base BASE. + If BASE is 0 the base is determined by the presence of a leading + zero, indicating octal or a leading "0x" or "0X", indicating hexadecimal. + If BASE is < 2 or > 36, it is reset to 10. + If ENDPTR is not NULL, a pointer to the character after the last + one converted is stored in *ENDPTR. */ +#if UNSIGNED +unsigned long int +#define strtol strtoul +#else +long int +#endif +strtol (nptr, endptr, base) + const char *nptr; + char **endptr; + int base; +{ + int negative; + register unsigned long int cutoff; + register unsigned int cutlim; + register unsigned long int i; + register const char *s; + register unsigned char c; + const char *save; + int overflow; + + if (base < 0 || base == 1 || base > 36) + base = 10; + + s = nptr; + + /* Skip white space. */ + while (isspace (*s)) + ++s; + if (*s == '\0') + goto noconv; + + /* Check for a sign. */ + if (*s == '-') + { + negative = 1; + ++s; + } + else if (*s == '+') + { + negative = 0; + ++s; + } + else + negative = 0; + + if (base == 16 && s[0] == '0' && toupper (s[1]) == 'X') + s += 2; + + /* If BASE is zero, figure it out ourselves. */ + if (base == 0) + { + if (*s == '0') + { + if (toupper (s[1]) == 'X') + { + s += 2; + base = 16; + } + else + base = 8; + } + else + base = 10; + } + + /* Save the pointer so we can check later if anything happened. */ + save = s; + + cutoff = ULONG_MAX / (unsigned long int) base; + cutlim = ULONG_MAX % (unsigned long int) base; + + overflow = 0; + i = 0; + for (c = *s; c != '\0'; c = *++s) + { + if (isdigit (c)) + c -= '0'; + else if (isalpha (c)) + c = toupper (c) - 'A' + 10; + else + break; + if (c >= base) + break; + /* Check for overflow. */ + if (i > cutoff || (i == cutoff && c > cutlim)) + overflow = 1; + else + { + i *= (unsigned long int) base; + i += c; + } + } + + /* Check if anything actually happened. */ + if (s == save) + goto noconv; + + /* Store in ENDPTR the address of one character + past the last character we converted. */ + if (endptr != NULL) + *endptr = (char *) s; + +#if !UNSIGNED + /* Check for a value that is within the range of + `unsigned long int', but outside the range of `long int'. */ + if (i > (negative ? + -(unsigned long int) LONG_MIN : (unsigned long int) LONG_MAX)) + overflow = 1; +#endif + + if (overflow) + { + errno = ERANGE; +#if UNSIGNED + return ULONG_MAX; +#else + return negative ? LONG_MIN : LONG_MAX; +#endif + } + + /* Return the result of the appropriate sign. */ + return (negative ? -i : i); + +noconv:; + /* There was no number to convert. */ + if (endptr != NULL) + *endptr = (char *) nptr; + return 0L; +} |