diff options
Diffstat (limited to 'libc/stdlib/strto_l.c')
| -rw-r--r-- | libc/stdlib/strto_l.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/libc/stdlib/strto_l.c b/libc/stdlib/strto_l.c new file mode 100644 index 000000000..a83cf4095 --- /dev/null +++ b/libc/stdlib/strto_l.c @@ -0,0 +1,192 @@ +/* + * Copyright (C) 2000 Manuel Novoa III + * + * Notes: + * + * The primary objective of this implementation was minimal size. + * + * Note: Assumes char layout 0-9.*A-Z.*a-z for ordinals values. + * + * There are a couple of compile-time options below. + * + */ + +/*****************************************************************************/ +/* OPTIONS */ +/*****************************************************************************/ + +/* Set if we want strtod to set errno appropriately. */ +/* NOTE: Implies _STRTO_ENDPTR below */ +#define _STRTO_ERRNO 0 + +/* Set if we want support for the endptr arg. */ +/* Implied by _STRTO_ERRNO. */ +#define _STRTO_ENDPTR 1 + +/*****************************************************************************/ +/* Don't change anything that follows. */ +/*****************************************************************************/ + +#if _STRTO_ERRNO +#undef _STRTO_ENDPTR +#define _STRTO_ENDPTR 1 +#endif + +/*****************************************************************************/ + +/* Are there actually any machines where this might fail? */ +#if 'A' > 'a' +#error ordering assumption violated : 'A' > 'a' +#endif + +#include <stdlib.h> +#include <limits.h> +#include <ctype.h> + +#if _STRTO_ERRNO +#include <errno.h> +#endif + +unsigned long _strto_l(const char *str, char **endptr, int base, int uflag); + +#if L_strto_l + +/* + * This is the main work fuction which handles both strtol (uflag = 0) and + * strtoul (uflag = 1). + */ + +unsigned long _strto_l(const char *str, char **endptr, int base, int uflag) +{ + unsigned long number = 0; + unsigned long cutoff; + char *pos = (char *) str; +#if _STRTO_ENDPTR + char *fail_char = (char *) str; +#endif + int digit, cutoff_digit; + int negative; + + while (isspace(*pos)) { /* skip leading whitespace */ + ++pos; + } + + /* handle optional sign */ + negative = 0; + switch(*pos) { + case '-': negative = 1; /* fall through to increment pos */ + case '+': ++pos; + } + + if ((base == 16) && (*pos == '0')) { /* handle option prefix */ + ++pos; +#if _STRTO_ENDPTR + fail_char = pos; +#endif + if ((*pos == 'x') || (*pos == 'X')) { + ++pos; + } + } + + if (base == 0) { /* dynamic base */ + base = 10; /* default is 10 */ + if (*pos == '0') { + ++pos; + base -= 2; /* now base is 8 (or 16) */ +#if _STRTO_ENDPTR + fail_char = pos; +#endif + if ((*pos == 'x') || (*pos == 'X')) { + base += 8; /* base is 16 */ + ++pos; + } + } + } + + if ((base < 2) || (base > 36)) { /* illegal base */ + goto DONE; + } + + cutoff = ULONG_MAX / base; + cutoff_digit = ULONG_MAX - cutoff * base; + + while (1) { + digit = 40; + if ((*pos >= '0') && (*pos <= '9')) { + digit = (*pos - '0'); + } else if (*pos >= 'a') { + digit = (*pos - 'a' + 10); + } else if (*pos >= 'A') { + digit = (*pos - 'A' + 10); + } else break; + + if (digit >= base) { + break; + } + + ++pos; +#if _STRTO_ENDPTR + fail_char = pos; +#endif + + /* adjust number, with overflow check */ + if ((number > cutoff) + || ((number == cutoff) && (digit > cutoff_digit))) { + number = ULONG_MAX; + if (uflag) { + negative = 0; /* since unsigned returns ULONG_MAX */ + } +#if _STRTO_ERRNO + errno = ERANGE; +#endif + } else { + number = number * base + digit; + } + + } + + DONE: +#if _STRTO_ENDPTR + if (endptr) { + *endptr = fail_char; + } +#endif + + if (negative) { + if (!uflag && (number > ((unsigned long)(-(1+LONG_MIN)))+1)) { +#if _STRTO_ERRNO + errno = ERANGE; +#endif + return (unsigned long) LONG_MIN; + } + return (unsigned long)(-((long)number)); + } else { + if (!uflag && (number > (unsigned long) LONG_MAX)) { +#if _STRTO_ERRNO + errno = ERANGE; +#endif + return LONG_MAX; + } + return number; + } +} + +#endif + +#if L_strtoul + +unsigned long strtoul(const char *str, char **endptr, int base) +{ + return _strto_l(str, endptr, base, 1); +} + +#endif + +#if L_strtol + +long strtol(const char *str, char **endptr, int base) +{ + return _strto_l(str, endptr, base, 0); +} + +#endif |