pebble/platform/tintin/boot/libc/string/strtol.c
2025-01-27 11:38:16 -08:00

81 lines
2.1 KiB
C

/*
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
///////////////////////////////////////
// Implements:
// long int strtol(const char *nptr, char **endptr, int base);
#include <ctype.h>
#include <string.h>
#include <stdint.h>
#include <limits.h>
#include <stdbool.h>
intmax_t strtoX_core(const char * restrict nptr, char ** restrict endptr, int base, bool do_errors,
intmax_t max, intmax_t min) {
intmax_t value = 0;
int sign = 1;
while (isspace((int)*nptr)) {
nptr++;
}
switch (*nptr) {
case '+': sign = 1; nptr++; break;
case '-': sign = -1; nptr++; break;
}
if (nptr[0] == '0' && nptr[1] == 'x' && (base == 0 || base == 16)) {
base = 16;
nptr += 2;
} else if (nptr[0] == '0' && (base == 0 || base == 8)) {
base = 8;
nptr++;
} else if (base == 0) {
base = 10;
}
// We break on '\0' anyways
for (;;) {
char ch = *nptr;
if (ch >= '0' && ch <= '9') {
ch = ch - '0';
} else if (ch >= 'A' && ch <= 'Z') {
ch = ch - 'A' + 10;
} else if (ch >= 'a' && ch <= 'z') {
ch = ch - 'a' + 10;
} else { // This will catch '\0'
break;
}
if (ch >= base) {
break;
}
value *= base;
value += ch;
if (do_errors) {
if ((sign > 0) && (value > max)) {
value = max;
} else if ((sign < 0) && (-value < min)) {
value = -min;
}
}
nptr++;
}
if (endptr) {
*endptr = (char*)nptr;
}
return value * sign;
}
long int strtol(const char * restrict nptr, char ** restrict endptr, int base) {
return strtoX_core(nptr, endptr, base, true, INT_MAX, INT_MIN);
}