isfshax/stage2ldr/string.c

/*  string.c -- standard C string-manipulation functions.

Copyright (C) 2008      Segher Boessenkool <segher@kernel.crashing.org>
Copyright (C) 2009      Haxx Enterprises <bushing@gmail.com>

Portions taken from the Public Domain C Library (PDCLib).
https://negix.net/trac/pdclib

# This code is licensed to you under the terms of the GNU GPL, version 2;
# see file COPYING or http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
*/

#include "string.h"

size_t strlen(const char *s)
{
    size_t len;

    for (len = 0; s[len]; len++)
        ;

    return len;
}

size_t strnlen(const char *s, size_t count)
{
    size_t len;

    for (len = 0; s[len] && len < count; len++)
        ;

    return len;
}

void *memset(void *b, int c, size_t len)
{
    size_t i;

    for (i = 0; i < len; i++)
        ((unsigned char *)b)[i] = c;

    return b;
}

void *memcpy(void *dst, const void *src, size_t len)
{
    size_t i;

    for (i = 0; i < len; i++)
        ((unsigned char *)dst)[i] = ((unsigned char *)src)[i];

    return dst;
}

int memcmp(const void *s1, const void *s2, size_t len)
{
    size_t i;
    const unsigned char * p1 = (const unsigned char *) s1;
    const unsigned char * p2 = (const unsigned char *) s2;

    for (i = 0; i < len; i++)
        if (p1[i] != p2[i]) return p1[i] - p2[i];

    return 0;
}

int strcmp(const char *s1, const char *s2)
{
    size_t i;

    for (i = 0; s1[i] && s1[i] == s2[i]; i++)
        ;

    return s1[i] - s2[i];
}

int strncmp(const char *s1, const char *s2, size_t n)
{
    size_t i;

    for (i = 0; i < n && s1[i] && s1[i] == s2[i]; i++)
        ;
    if (i == n) return 0;
    return s1[i] - s2[i];
}

char * strchr(const char *s, int c)
{
    size_t i;

    for (i = 0; s[i]; i++)
        if (s[i] == (char)c) return (char *)s + i;

    return NULL;
}

size_t strspn(const char *s1, const char *s2)
{
    size_t len = 0;
    const char *p;

    while (s1[len]) {
        p = s2;
        while (*p) {
            if (s1[len] == *p)
                break;

            ++p;
        }
        if (!*p)
            return len;

        ++len;
    }

    return len;
}

size_t strcspn(const char *s1, const char *s2)
{
    size_t len = 0;
    const char *p;

    while (s1[len]) {
        p = s2;
        while (*p)
            if (s1[len] == *p++)
                return len;

        ++len;
    }

    return len;
}