stdImpl.c

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#include "stdImpl.h"

char* stdimpl_strcpy(char *dst, const char *src)
{
    char *start = dst;
    char c;
    do {
        c = *src;
        *dst = c;
        src++;
        dst++;
    } while (c);
    return start;
}

char* stdimpl_strcat(char *dst, const char *src)
{
    char *start = dst;
    char c;
    do {
        c = *dst;
        dst++;
    } while (c);
    dst--;
    do {
        c = *src;
        *dst = c;
        src++;
        dst++;
    } while (c);
    return start;
}

char* stdimpl_strncat(char *dst, const char *src,unsigned int count)
{
    char *start = dst;
    char c;
    do {
        c = *dst;
        dst++;
    } while (c);
    dst--;
    if (count) {
        do {
            c = *src;
            *dst = c;
            src++;
            dst++;
            count--;
        } while (c && count);
        *dst = '\0';
    }
    return start;
}

int stdimpl_strlen(const char *str)
{
    const char *estr = str;
    char c;
    do {
        c = *estr;
        estr++;
    } while (c);
    return ((int)(estr - str - 1));
}

int stdimpl_strcmp(const char *s1, const char *s2)
{
    char c1,c2;
    do {
        c1 = *s1++;
        c2 = *s2++;
    } while ((c1) && (c2) && (c1==c2));
    return c1 - c2;
}

int stdimpl_memcmp(const void *p1, const void *p2, int s)
{
    char *s1 = (char*)p1;
    char *s2 = (char*)p2;
    char c1,c2;
    do {
        c1 = *s1++;
        c2 = *s2++;
        s--;
    } while ((c1==c2) && s);
    return c1 - c2;
}

static char* _xtoa(unsigned long v,char *string, int r, int is_neg)
{
    char *start = string;
    char buf[33],*p;

    p = buf;

    do {
        *p++ = "0123456789abcdef"[(v % r) & 0xf];
    } while (v /= r);

    if (is_neg) {
        *p++ = '-';
    }

    do {
        *string++ = *--p;
    } while (buf != p);

    *string = '\0';

    return start;
}

char* stdimpl_itoa(long v,char *string,int r)
{
    if ((r == 10) && (v < 0)) {
        return _xtoa((unsigned long)(-v), string, r, 1);
    }
    return _xtoa((unsigned long)(v), string, r, 0);
}

char* stdimpl_utoa(unsigned long v,char *string,int r)
{
    return _xtoa((unsigned long)(v), string, r, 0);
}