string.c

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#include <assert.h>
#include <ctype.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
 
char *strdup(const char *s)
{
        if (!ENV_RAMSTAGE)
                dead_code();    /* This can't be used without malloc(). */
 
        size_t sz = strlen(s) + 1;
        char *d = malloc(sz);
        if (d)
                memcpy(d, s, sz);
        return d;
}
 
char *strconcat(const char *s1, const char *s2)
{
        if (!ENV_RAMSTAGE)
                dead_code();    /* This can't be used without malloc(). */
 
        size_t sz_1 = strlen(s1);
        size_t sz_2 = strlen(s2);
        char *d = malloc(sz_1 + sz_2 + 1);
        if (d) {
                memcpy(d, s1, sz_1);
                memcpy(d + sz_1, s2, sz_2 + 1);
        }
        return d;
}
 
size_t strnlen(const char *src, size_t max)
{
        size_t i = 0;
        while ((*src++) && (i < max))
                i++;
        return i;
}
 
size_t strlen(const char *src)
{
        size_t i = 0;
        while (*src++)
                i++;
        return i;
}
 
char *strchr(const char *s, int c)
{
        do {
                if (*s == c)
                        return (char *)s;
        } while (*s++);
 
        return NULL;
}
 
char *strrchr(const char *s, int c)
{
        char *p = NULL;
 
        do {
                if (*s == c)
                        p = (char *)s;
        } while (*s++);
 
        return p;
}
 
char *strncpy(char *to, const char *from, int count)
{
        char *ret = to;
        char data;
 
        while (count > 0) {
                count--;
                data = *from++;
                *to++  = data;
                if (data == '\0')
                        break;
        }
 
        while (count > 0) {
                count--;
                *to++ = '\0';
        }
        return ret;
}
 
char *strcpy(char *dst, const char *src)
{
        char *ptr = dst;
 
        while (*src)
                *dst++ = *src++;
        *dst = '\0';
 
        return ptr;
}
 
int strcmp(const char *s1, const char *s2)
{
        int r;
 
        while ((r = (*s1 - *s2)) == 0 && *s1) {
                s1++;
                s2++;
        }
        return r;
}
 
int strncmp(const char *s1, const char *s2, int maxlen)
{
        int i;
 
        for (i = 0; i < maxlen; i++) {
                if ((s1[i] != s2[i]) || (s1[i] == '\0'))
                        return s1[i] - s2[i];
        }
 
        return 0;
}
 
unsigned int skip_atoi(char **s)
{
        unsigned int i = 0;
 
        while (isdigit(**s))
                i = i*10 + *((*s)++) - '0';
        return i;
}
 
int strspn(const char *str, const char *spn)
{
        int ret = 0;
 
        while (*str != 0) {
                const char *p;
                for (p = spn; *str != *p; p++)
                        if (*p == '\0')
                                return ret;
                ret++;
                str++;
        }
        return ret;
}
 
int strcspn(const char *str, const char *spn)
{
        int ret = 0;
 
        while (*str != 0) {
                const char *p;
                for (p = spn; *p != '\0'; p++)
                        if (*p == *str)
                                return ret;
                ret++;
                str++;
        }
        return ret;
}
 
char *strstr(const char *haystack, const char *needle)
{
        size_t needle_len = strlen(needle);
        for (; *haystack; haystack++) {
                if (!strncmp(haystack, needle, needle_len))
                        return (char *)haystack;
        }
        return NULL;
}
 
char *strtok_r(char *str, const char *delim, char **ptr)
{
        char *start;
        char *end;
 
        if (str == NULL)
                str = *ptr;
        start = str + strspn(str, delim);
        if (start[0] == '\0')
                return NULL;
 
        end = start + strcspn(start, delim);
        *ptr = end;
        if (end[0] != '\0')
                *(*ptr)++ = '\0';
        return start;
}
 
char *strtok(char *str, const char *delim)
{
        static char *strtok_ptr;
 
        return strtok_r(str, delim, &strtok_ptr);
}
 
long atol(const char *str)
{
        long ret = 0;
        long sign = 1;
 
        str += strspn(str, " \t\n\r\f\v");
 
        if (*str == '+') {
                sign = 1;
                str++;
        } else if (*str == '-') {
                sign = -1;
                str++;
        }
 
        while (isdigit(*str)) {
                ret *= 10;
                ret += *str++ - '0';
        }
        return ret * sign;
}