diff options
Diffstat (limited to 'lib/libc/stdlib/strtox.c')
| -rw-r--r-- | lib/libc/stdlib/strtox.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/lib/libc/stdlib/strtox.c b/lib/libc/stdlib/strtox.c new file mode 100644 index 00000000..9d72954a --- /dev/null +++ b/lib/libc/stdlib/strtox.c @@ -0,0 +1,270 @@ +#include <ctype.h> +#include <float.h> +#include <errno.h> +#include <strings.h> +#include <limits.h> +#include <math.h> +#include <stdlib.h> + +static unsigned long long +__scanint(const char *s, int base, unsigned long long lim, int *neg, char **end) +{ + unsigned long long res = 0; + int digit, any = 0; + + while (isspace((unsigned char)*s)) + s++; + + *neg = 0; + if (*s == '+' || *s == '-') { + *neg = (*s == '-'); + s++; + } + + if ((base == 0 || base == 16) && s[0] == '0' && + (s[1] == 'x' || s[1] == 'X')) { + base = 16; + s += 2; + } else if (base == 0 && *s == '0') { + base = 8; + s++; + } else if (base == 0) { + base = 10; + } + + for (; *s; s++) { + unsigned char c = *s; + if (isdigit(c)) + digit = c - '0'; + else if (isalpha(c)) + digit = toupper(c) - 'A' + 10; + else + break; + + if (digit >= base) + break; + if (res > (lim - digit) / base) { + errno = ERANGE; + res = lim; + any = 1; + while (1) { + if (isalnum((unsigned char)*++s) == 0) + break; + } + break; + } + res = res * base + digit; + any = 1; + } + + if (end) + *end = (char *)(any ? s : s - 1); + + return res; +} + +static long double __scanfloat(const char *s, char **end) +{ + long double value = 0.0; + long double frac = 0.0; + long double sign = 1.0; + long double scale = 1.0; + int exp_sign = 1; + long exp_val = 0; + int got_digit = 0; + + while (isspace((unsigned char)*s)) + s++; + + if (*s == '+' || *s == '-') { + if (*s == '-') + sign = -1.0; + s++; + } + + if (strncasecmp(s, "inf", 3) == 0) { + s += 3; + if (strncasecmp(s, "inity", 5) == 0) + s += 5; + if (end) + *end = (char *)s; + return sign * INFINITY; + } + if (strncasecmp(s, "nan", 3) == 0) { + s += 3; + if (*s == '(') { + s++; + while (*s && *s != ')') + s++; + if (*s == ')') + s++; + } + if (end) + *end = (char *)s; + return NAN; + } + + while (isdigit((unsigned char)*s)) { + value = value * 10.0 + (*s - '0'); + s++; + got_digit = 1; + } + + if (*s == '.') { + s++; + while (isdigit((unsigned char)*s)) { + value = value * 10.0 + (*s - '0'); + scale *= 10.0; + s++; + got_digit = 1; + } + } + + if (!got_digit) { + if (end) + *end = (char *)s; + return 0.0; + } + + value = value / scale; + + if (*s == 'e' || *s == 'E') { + const char *p = ++s; + if (*p == '+' || *p == '-') { + exp_sign = (*p == '-') ? -1 : 1; + p++; + } + while (isdigit((unsigned char)*p)) { + exp_val = exp_val * 10 + (*p - '0'); + p++; + } + s = p; + value *= powl(10.0, exp_sign * exp_val); + } + + if (end) + *end = (char *)s; + + return sign * value; +} + +long strtol(const char *restrict nptr, char **restrict endptr, int base) +{ + int neg; + unsigned long long lim; + unsigned long long v; + + const char *p = nptr; + while (isspace((unsigned char)*p)) + p++; + int is_neg = (*p == '-'); + lim = is_neg ? (unsigned long long)LONG_MAX + 1ULL : LONG_MAX; + + v = __scanint(nptr, base, lim, &neg, endptr); + + if (neg) + return (v == lim) ? LONG_MIN : -(long)v; + else + return (v > LONG_MAX) ? (errno = ERANGE, LONG_MAX) : (long)v; +} + +long long strtoll(const char *restrict nptr, char **restrict endptr, int base) +{ + int neg; + unsigned long long lim; + unsigned long long v; + + const char *p = nptr; + while (isspace((unsigned char)*p)) + p++; + int is_neg = (*p == '-'); + + lim = is_neg ? (unsigned long long)LLONG_MAX + 1ULL : LLONG_MAX; + + v = __scanint(nptr, base, lim, &neg, endptr); + + if (neg) { + if (v == lim) + return LLONG_MIN; + else + return -(long long)v; + } else { + if (v > LLONG_MAX) { + errno = ERANGE; + return LLONG_MAX; + } else + return (long long)v; + } +} + +unsigned long strtoul(const char *restrict nptr, char **restrict endptr, + int base) +{ + int neg; + unsigned long long v; + + v = __scanint(nptr, base, ULONG_MAX, &neg, endptr); + + if (neg) { + errno = EINVAL; + return 0; + } + + if (v > ULONG_MAX) { + errno = ERANGE; + return ULONG_MAX; + } + + return (unsigned long)v; +} + +unsigned long long strtoull(const char *restrict nptr, char **restrict endptr, + int base) +{ + int neg; + unsigned long long v; + + v = __scanint(nptr, base, ULLONG_MAX, &neg, endptr); + + if (neg) { + errno = EINVAL; + return 0; + } + + if (v > ULLONG_MAX) { + errno = ERANGE; + return ULLONG_MAX; + } + + return v; +} + +float strtof(const char *restrict nptr, char **restrict endptr) +{ + long double val = __scanfloat(nptr, endptr); + + if (val > FLT_MAX) { + errno = ERANGE; + return HUGE_VALF; + } else if (val < -FLT_MAX) { + errno = ERANGE; + return -HUGE_VALF; + } + + return (float)val; +} + +long double strtold(const char *restrict nptr, char **restrict endptr) +{ + long double val = __scanfloat(nptr, endptr); + + if (val > LDBL_MAX) { + errno = ERANGE; + return LDBL_MAX; + } else if (val < -LDBL_MAX) { + errno = ERANGE; + return -LDBL_MAX; + } + + return val; +} |