#include <inttypes.h>

#include "macro.h"
#include "byteswap.h"

static void byteswap16(void *_dst, size_t dstr, const void *_src, size_t sstr, size_t bytes) {
    uint16_t *dst = _dst;
    const uint16_t *src = _src;
    unsigned n = bytes / sizeof(uint16_t);

    for (; n > 0; n--) {
        *dst = (*src >> 8) | (*src << 8);
        src += sstr / sizeof(uint16_t);
        dst += dstr / sizeof(uint16_t);
    }
}

static void byteswap24(void *_dst, size_t dstr, const void *_src, size_t sstr, size_t bytes) {
    uint8_t *dst = _dst;
    const uint8_t *src = _src;
    unsigned n = bytes / (sizeof(uint8_t)*3);
    
    for (; n > 0; n--) {
        dst[0] = src[2];
        dst[2] = src[0];
        
        src += sstr / (sizeof(uint8_t)*3);
        dst += dstr / (sizeof(uint8_t)*3);
    }
}

static void byteswap32(void *_dst, size_t dstr, const void *_src, size_t sstr, size_t bytes) {
    uint32_t *dst = _dst;
    const uint32_t *src = _src;
    unsigned n = bytes / sizeof(uint32_t);
    
    for (; n > 0; n--) {
        *dst = (*src << 24) | ((*src & 0xFF00) << 8) | ((*src >> 8) & 0xFF00) | (*src >> 24);
        src += sstr / sizeof(uint32_t);
        dst += dstr / sizeof(uint32_t);
    }
}

sa_byteswap_func_t sa_get_byteswap_func(sa_pcm_format_t f) {
    
    static const sa_byteswap_func_t funcs[_SA_PCM_FORMAT_MAX] = {
        [SA_PCM_FORMAT_S16_RE] = byteswap16,
        [SA_PCM_FORMAT_S24_RE] = byteswap24,
        [SA_PCM_FORMAT_S32_RE] = byteswap32,
        [SA_PCM_FORMAT_FLOAT32_BE] = byteswap32,
    };

    sa_assert(f < _SA_PCM_FORMAT_MAX); 

    return funcs[f];
}