string.c

Go to the documentation of this file.

/*
 * arch/arm/boot/compressed/string.c
 *
 * Small subset of simple string routines
 */

#include <linux/string.h>

void *memcpy(void *__dest, __const void *__src, size_t __n)
{
    int i = 0;
    unsigned char *d = (unsigned char *)__dest, *s = (unsigned char *)__src;

    for (i = __n >> 3; i > 0; i--) {
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
    }

    if (__n & 1 << 2) {
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
        *d++ = *s++;
    }

    if (__n & 1 << 1) {
        *d++ = *s++;
        *d++ = *s++;
    }

    if (__n & 1)
        *d++ = *s++;

    return __dest;
}

void *memmove(void *__dest, __const void *__src, size_t count)
{
    unsigned char *d = __dest;
    const unsigned char *s = __src;

    if (__dest == __src)
        return __dest;

    if (__dest < __src)
        return memcpy(__dest, __src, count);

    while (count--)
        d[count] = s[count];
    return __dest;
}

size_t strlen(const char *s)
{
    const char *sc = s;

    while (*sc != '\0')
        sc++;
    return sc - s;
}

int memcmp(const void *cs, const void *ct, size_t count)
{
    const unsigned char *su1 = cs, *su2 = ct, *end = su1 + count;
    int res = 0;

    while (su1 < end) {
        res = *su1++ - *su2++;
        if (res)
            break;
    }
    return res;
}

int strcmp(const char *cs, const char *ct)
{
    unsigned char c1, c2;
    int res = 0;

    do {
        c1 = *cs++;
        c2 = *ct++;
        res = c1 - c2;
        if (res)
            break;
    } while (c1);
    return res;
}

void *memchr(const void *s, int c, size_t count)
{
    const unsigned char *p = s;

    while (count--)
        if ((unsigned char)c == *p++)
            return (void *)(p - 1);
    return NULL;
}

char *strchr(const char *s, int c)
{
    while (*s != (char)c)
        if (*s++ == '\0')
            return NULL;
    return (char *)s;
}

#undef memset

void *memset(void *s, int c, size_t count)
{
    char *xs = s;
    while (count--)
        *xs++ = c;
    return s;
}

void __memzero(void *s, size_t count)
{
    memset(s, 0, count);
}