/* $Id: kLdrHlp-gcc.c 2944 2007-01-13 15:55:40Z bird $ */
/** @file
 *
 * kLdr - The Dynamic Loader, Helper Functions for GCC.
 *
 * Copyright (c) 2006 knut st. osmundsen <bird@anduin.net>
 *
 *
 * This file is part of kLdr.
 *
 * kLdr is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * kLdr is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with kLdr; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <kLdr.h>
#include "kLdrHlp.h"


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/


void *memchr(const void *pv, int ch, size_t cb)
{
    const char *pb = pv;
    while (cb-- > 0)
    {
        if (*pb == ch)
            return (void *)pb;
        pb++;
    }
    return 0;
}


int memcmp(const void *pv1, const void *pv2, size_t cb)
{
    /*
     * Pointer size pointer size.
     */
    if (    cb > 16
        &&  !((uintptr_t)pv1 & (sizeof(void *) - 1))
        &&  !((uintptr_t)pv2 & (sizeof(void *) - 1)) )
    {
        const uintptr_t *pu1 = pv1;
        const uintptr_t *pu2 = pv2;
        while (cb >= sizeof(uintptr_t))
        {
            const uintptr_t u1 = *pu1++;
            const uintptr_t u2 = *pu2++;
            if (u1 != u2)
                return u1 > u2 ? 1 : -1;
            cb -= sizeof(uintptr_t);
        }
        if (!cb)
            return 0;
        pv1 = (const void *)pu1;
        pv2 = (const void *)pu2;
    }

    /*
     * Byte by byte.
     */
    if (cb)
    {
        const unsigned char *pb1 = pv1;
        const unsigned char *pb2 = pv2;
        while (cb-- > 0)
        {
            const unsigned char b1 = *pb1++;
            const unsigned char b2 = *pb2++;
            if (b1 != b2)
                return b1 > b2 ? 1 : -1;
        }
    }
    return 0;
}


void *memcpy(void *pv1, const void *pv2, size_t cb)
{
    void *pv1Start = pv1;

    /*
     * Pointer size pointer size.
     */
    if (    cb > 16
        &&  !((uintptr_t)pv1 & (sizeof(void *) - 1))
        &&  !((uintptr_t)pv2 & (sizeof(void *) - 1)) )
    {
        uintptr_t       *pu1 = pv1;
        const uintptr_t *pu2 = pv2;
        while (cb >= sizeof(uintptr_t))
        {
            cb -= sizeof(uintptr_t);
            *pu1++ = *pu2++;
        }
        if (!cb)
            return 0;
        pv1 = (void *)pu1;
        pv2 = (const void *)pu2;
    }

    /*
     * byte by byte
     */
    if (cb)
    {
        unsigned char       *pb1 = pv1;
        const unsigned char *pb2 = pv2;
        while (cb-- > 0)
            *pb1++ = *pb2++;
    }

    return pv1Start;
}

void *memset(void *pv, int ch, size_t cb)
{
    void *pvStart = pv;

    /*
     * Pointer size pointer size.
     */
    if (    cb > 16
        &&  !((uintptr_t)pv & (sizeof(void *) - 1)))
    {
        uintptr_t  *pu = pv;
        uintptr_t   u = ch | (ch << 8);
        u |= u << 16;
#if defined(__AMD64__)
        u |= u << 32;
#endif

        while (cb >= sizeof(uintptr_t))
        {
            cb -= sizeof(uintptr_t);
            *pu++ = u;
        }
    }

    /*
     * Byte by byte
     */
    if (cb)
    {
        unsigned char *pb = pv;
        while (cb-- > 0)
            *pb++ = ch;
    }
    return pvStart;
}


int strcmp(const char *psz1, const char *psz2)
{
    for (;;)
    {
        const char ch1 = *psz1++;
        const char ch2 = *psz2++;
        if (ch1 != ch2)
            return (int)ch1 - (int)ch2;
        if (!ch1)
            return 0;
    }
}


int strncmp(const char *psz1, const char *psz2, size_t cch)
{
    while (cch-- > 0)
    {
        const char ch1 = *psz1++;
        const char ch2 = *psz2++;
        if (ch1 != ch2)
            return (int)ch1 - (int)ch2;
        if (!ch1)
            break;
    }
    return 0;
}

char *strchr(const char *psz, int ch)
{
    for (;;)
    {
        const char chCur = *psz;
        if (chCur == ch)
            return (char *)psz;
        if (!chCur)
            return 0;
        psz++;
    }
}

size_t strlen(const char *psz)
{
    const char *pszStart = psz;
    while (*psz)
        psz++;
    return psz - pszStart;
}