HelenOS sources
This source file includes following definitions.
- pcm_format_same
- pcm_format_silence
- pcm_format_mix
- pcm_format_convert_and_mix
- get_normalized_sample
#include <assert.h>
#include <byteorder.h>
#include <errno.h>
#include <macros.h>
#include <stdio.h>
#include <inttypes.h>
#include <limits.h>
#include "format.h"
#define float_le2host(x) (x)
#define float_be2host(x) (x)
#define host2float_le(x) (x)
#define host2float_be(x) (x)
#define from(x, type, endian) (float)(type ## _ ## endian ## 2host(x))
#define to(x, type, endian) (float)(host2 ## type ## _ ## endian(x))
const pcm_format_t AUDIO_FORMAT_DEFAULT = {
        .channels = 2,
        .sampling_rate = 44100,
        .sample_format = PCM_SAMPLE_SINT16_LE,
};
const pcm_format_t AUDIO_FORMAT_ANY = {
        .channels = 0,
        .sampling_rate = 0,
        .sample_format = 0,
};
static float get_normalized_sample(const void *buffer, size_t size,
    unsigned frame, unsigned channel, const pcm_format_t *f);
bool pcm_format_same(const pcm_format_t *a, const pcm_format_t *b)
{
        assert(a);
        assert(b);
        return
            a->sampling_rate == b->sampling_rate &&
            a->channels == b->channels &&
            a->sample_format == b->sample_format;
}
void pcm_format_silence(void *dst, size_t size, const pcm_format_t *f)
{
#define SET_NULL(type, endian, nullv) \
do { \
        type *buffer = dst; \
        const size_t sample_count = size / sizeof(type); \
        for (unsigned i = 0; i < sample_count; ++i) { \
                buffer[i] = to((type)nullv, type, endian); \
        } \
} while (0)
        switch (f->sample_format) {
        case PCM_SAMPLE_UINT8:
                SET_NULL(uint8_t, le, INT8_MIN);
                break;
        case PCM_SAMPLE_SINT8:
                SET_NULL(int8_t, le, 0);
                break;
        case PCM_SAMPLE_UINT16_LE:
                SET_NULL(uint16_t, le, INT16_MIN);
                break;
        case PCM_SAMPLE_SINT16_LE:
                SET_NULL(int16_t, le, 0);
                break;
        case PCM_SAMPLE_UINT16_BE:
                SET_NULL(uint16_t, be, INT16_MIN);
                break;
        case PCM_SAMPLE_SINT16_BE:
                SET_NULL(int16_t, be, 0);
                break;
        case PCM_SAMPLE_UINT32_LE:
                SET_NULL(uint32_t, le, INT32_MIN);
                break;
        case PCM_SAMPLE_SINT32_LE:
                SET_NULL(int32_t, le, 0);
                break;
        case PCM_SAMPLE_UINT32_BE:
                SET_NULL(uint32_t, be, INT32_MIN);
                break;
        case PCM_SAMPLE_SINT32_BE:
                SET_NULL(int32_t, le, 0);
                break;
        case PCM_SAMPLE_UINT24_32_LE:
        case PCM_SAMPLE_SINT24_32_LE:
        case PCM_SAMPLE_UINT24_32_BE:
        case PCM_SAMPLE_SINT24_32_BE:
        case PCM_SAMPLE_UINT24_LE:
        case PCM_SAMPLE_SINT24_LE:
        case PCM_SAMPLE_UINT24_BE:
        case PCM_SAMPLE_SINT24_BE:
        case PCM_SAMPLE_FLOAT32:
        default:
                break;
        }
#undef SET_NULL
}
errno_t pcm_format_mix(void *dst, const void *src, size_t size, const pcm_format_t *f)
{
        return pcm_format_convert_and_mix(dst, size, src, size, f, f);
}
errno_t pcm_format_convert_and_mix(void *dst, size_t dst_size, const void *src,
    size_t src_size, const pcm_format_t *sf, const pcm_format_t *df)
{
        if (!dst || !src || !sf || !df)
                return EINVAL;
        const size_t src_frame_size = pcm_format_frame_size(sf);
        if ((src_size % src_frame_size) != 0)
                return EINVAL;
        const size_t dst_frame_size = pcm_format_frame_size(df);
        if ((dst_size % dst_frame_size) != 0)
                return EINVAL;
        
#define LOOP_ADD(type, endian, low, high) \
do { \
        const unsigned frame_count = dst_size / dst_frame_size; \
        for (size_t i = 0; i < frame_count; ++i) { \
                for (unsigned j = 0; j < df->channels; ++j) { \
                        const float a = \
                            get_normalized_sample(dst, dst_size, i, j, df);\
                        const float b = \
                            get_normalized_sample(src, src_size, i, j, sf);\
                        float c = (a + b); \
                        if (c < -1.0) c = -1.0; \
                        if (c > 1.0) c = 1.0; \
                        c += 1.0; \
                        c *= ((float)(type)high - (float)(type)low) / 2; \
                        c += (float)(type)low; \
                        type *dst_buf = dst; \
                        const unsigned pos = i * df->channels  + j; \
                        if (pos < (dst_size / sizeof(type))) \
                                dst_buf[pos] = to((type)c, type, endian); \
                } \
        } \
} while (0)
        switch (df->sample_format) {
        case PCM_SAMPLE_UINT8:
                LOOP_ADD(uint8_t, le, UINT8_MIN, UINT8_MAX);
                break;
        case PCM_SAMPLE_SINT8:
                LOOP_ADD(uint8_t, le, INT8_MIN, INT8_MAX);
                break;
        case PCM_SAMPLE_UINT16_LE:
                LOOP_ADD(uint16_t, le, UINT16_MIN, UINT16_MAX);
                break;
        case PCM_SAMPLE_SINT16_LE:
                LOOP_ADD(int16_t, le, INT16_MIN, INT16_MAX);
                break;
        case PCM_SAMPLE_UINT16_BE:
                LOOP_ADD(uint16_t, be, UINT16_MIN, UINT16_MAX);
                break;
        case PCM_SAMPLE_SINT16_BE:
                LOOP_ADD(int16_t, be, INT16_MIN, INT16_MAX);
                break;
        case PCM_SAMPLE_UINT24_32_LE:
        case PCM_SAMPLE_UINT32_LE: 
                LOOP_ADD(uint32_t, le, UINT32_MIN, UINT32_MAX);
                break;
        case PCM_SAMPLE_SINT24_32_LE:
        case PCM_SAMPLE_SINT32_LE:
                LOOP_ADD(int32_t, le, INT32_MIN, INT32_MAX);
                break;
        case PCM_SAMPLE_UINT24_32_BE:
        case PCM_SAMPLE_UINT32_BE:
                LOOP_ADD(uint32_t, be, UINT32_MIN, UINT32_MAX);
                break;
        case PCM_SAMPLE_SINT24_32_BE:
        case PCM_SAMPLE_SINT32_BE:
                LOOP_ADD(int32_t, be, INT32_MIN, INT32_MAX);
                break;
        case PCM_SAMPLE_UINT24_LE:
        case PCM_SAMPLE_SINT24_LE:
        case PCM_SAMPLE_UINT24_BE:
        case PCM_SAMPLE_SINT24_BE:
        case PCM_SAMPLE_FLOAT32:
        default:
                return ENOTSUP;
        }
        return EOK;
#undef LOOP_ADD
}
static float get_normalized_sample(const void *buffer, size_t size,
    unsigned frame, unsigned channel, const pcm_format_t *f)
{
        assert(f);
        assert(buffer);
        if (channel >= f->channels)
                return 0.0f;
#define GET(type, endian, low, high) \
do { \
        const type *src = buffer; \
        const size_t sample_count = size / sizeof(type); \
        const size_t sample_pos = frame * f->channels + channel; \
        if (sample_pos >= sample_count) {\
                return 0.0f; \
        } \
        float sample = from(src[sample_pos], type, endian); \
         \
        sample -= (float)(type)low; \
         \
        sample /= (((float)(type)high - (float)(type)low) / 2.0f); \
        return sample - 1.0f; \
} while (0)
        switch (f->sample_format) {
        case PCM_SAMPLE_UINT8:
                GET(uint8_t, le, UINT8_MIN, UINT8_MAX);
        case PCM_SAMPLE_SINT8:
                GET(int8_t, le, INT8_MIN, INT8_MAX);
        case PCM_SAMPLE_UINT16_LE:
                GET(uint16_t, le, UINT16_MIN, UINT16_MAX);
        case PCM_SAMPLE_SINT16_LE:
                GET(int16_t, le, INT16_MIN, INT16_MAX);
        case PCM_SAMPLE_UINT16_BE:
                GET(uint16_t, be, UINT16_MIN, UINT16_MAX);
        case PCM_SAMPLE_SINT16_BE:
                GET(int16_t, be, INT16_MIN, INT16_MAX);
        case PCM_SAMPLE_UINT24_32_LE:
        case PCM_SAMPLE_UINT32_LE:
                GET(uint32_t, le, UINT32_MIN, UINT32_MAX);
        case PCM_SAMPLE_SINT24_32_LE:
        case PCM_SAMPLE_SINT32_LE:
                GET(int32_t, le, INT32_MIN, INT32_MAX);
        case PCM_SAMPLE_UINT24_32_BE:
        case PCM_SAMPLE_UINT32_BE:
                GET(uint32_t, be, UINT32_MIN, UINT32_MAX);
        case PCM_SAMPLE_SINT24_32_BE:
        case PCM_SAMPLE_SINT32_BE:
                GET(int32_t, le, INT32_MIN, INT32_MAX);
        case PCM_SAMPLE_UINT24_LE:
        case PCM_SAMPLE_SINT24_LE:
        case PCM_SAMPLE_UINT24_BE:
        case PCM_SAMPLE_SINT24_BE:
        case PCM_SAMPLE_FLOAT32:
        default:
                break;
        }
        return 0;
#undef GET
}
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