#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <kernaux/libc.h>

#include <stdbool.h>

#ifdef WITH_LIBC_ATOI
int atoi(const char *str)
{
    while (isspace(*str)) ++str;
    bool is_negative = false;
    switch (*str) {
    case '-': is_negative = true;
    case '+': ++str;
    }
    int result = 0;
    while (isdigit(*str)) result = 10 * result - (*str++ - '0');
    return is_negative ? result : -result;
}
#endif // WITH_LIBC_ATOI

#ifdef WITH_LIBC_ISDIGIT
int isdigit(const int c)
{
    return (unsigned)c - '0' < 10;
}
#endif // WITH_LIBC_ISDIGIT

#ifdef WITH_LIBC_ISSPACE
int isspace(const int c)
{
    return c == ' ' || (unsigned)c - '\t' < 5;
}
#endif // WITH_LIBC_ISSPACE

#ifdef WITH_LIBC_MEMSET
void *memset(void *s, int c, size_t n)
{
    char *ss = s;
    while (n-- > 0) *ss++ = c;
    return s;
}
#endif // WITH_LIBC_MEMSET

#ifdef WITH_LIBC_STRCPY
char *strcpy(char *dest, const char *src)
{
    char *tmp = dest;
    while ((*dest++ = *src++) != '\0');
    return tmp;
}
#endif // WITH_LIBC_STRCPY

#ifdef WITH_LIBC_STRLEN
size_t strlen(const char *s)
{
    const char *ss = s;
    while (*ss != '\0') ++ss;
    return ss - s;
}
#endif // WITH_LIBC_STRLEN

#ifdef WITH_LIBC_STRNLEN
size_t strnlen(const char *s, size_t maxlen)
{
    const char *ss = s;
    while (*ss != '\0' && maxlen--) ++ss;
    return ss - s;
}
#endif // WITH_LIBC_STRNLEN