shithub: mp3dec

ref: fa4c2ef5d00c4a136e6b59873151dea46e8d8023
dir: /minimp3_ex.h/

View raw version
#ifndef MINIMP3_EXT_H
#define MINIMP3_EXT_H
/*
    https://github.com/lieff/minimp3
    To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide.
    This software is distributed without any warranty.
    See <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
#include "minimp3.h"

#define MP3D_SEEK_TO_BYTE   0
#define MP3D_SEEK_TO_SAMPLE 1

#define MINIMP3_PREDECODE_FRAMES 2 /* frames to pre-decode and skip after seek (to fill internal structures) */
/*#define MINIMP3_SEEK_IDX_LINEAR_SEARCH*/ /* define to use linear index search instead of binary search on seek */
#define MINIMP3_RING_SIZE (128*1024)

#define MP3D_E_MEMORY -1

typedef struct
{
    mp3d_sample_t *buffer;
    size_t samples; /* channels included, byte size = samples*sizeof(mp3d_sample_t) */
    int channels, hz, layer, avg_bitrate_kbps;
} mp3dec_file_info_t;

typedef struct
{
    const uint8_t *buffer;
    size_t size;
} mp3dec_map_info_t;

typedef struct
{
    uint64_t sample;
    uint64_t offset;
} mp3dec_frame_t;

typedef struct
{
    mp3dec_frame_t *frames;
    size_t num_frames, capacity;
} mp3dec_index_t;

typedef int (*MP3D_READ_CB)(void *buf, size_t size, void *user_data);
typedef int (*MP3D_SEEK_CB)(size_t position);

typedef struct
{
    mp3dec_t mp3d;
    mp3dec_map_info_t file;
    mp3dec_index_t index;
    uint64_t offset, samples, detected_samples, start_offset, end_offset;
    mp3dec_frame_info_t info;
    mp3d_sample_t buffer[MINIMP3_MAX_SAMPLES_PER_FRAME];
#ifndef MINIMP3_NO_STDIO
    int is_file;
#endif
    int free_format_bytes;
    int seek_method, vbr_tag_found;
    int buffer_samples, buffer_consumed, to_skip, start_delay;
} mp3dec_ex_t;

typedef int (*MP3D_ITERATE_CB)(void *user_data, const uint8_t *frame, int frame_size, int free_format_bytes, size_t buf_size, size_t offset, mp3dec_frame_info_t *info);
typedef int (*MP3D_PROGRESS_CB)(void *user_data, size_t file_size, size_t offset, mp3dec_frame_info_t *info);

#ifdef __cplusplus
extern "C" {
#endif

/* decode whole buffer block */
void mp3dec_load_buf(mp3dec_t *dec, const uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
/* iterate through frames */
size_t mp3dec_iterate_buf(const uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data);
/* streaming decoder with seeking capability */
int mp3dec_ex_open_buf(mp3dec_ex_t *dec, const uint8_t *buf, size_t buf_size, int seek_method);
int mp3dec_ex_open_cb(mp3dec_ex_t *dec, MP3D_READ_CB read_cb, void *read_user_data, MP3D_SEEK_CB seek_cb, void *seek_user_data, int seek_method);
void mp3dec_ex_close(mp3dec_ex_t *dec);
int mp3dec_ex_seek(mp3dec_ex_t *dec, uint64_t position);
size_t mp3dec_ex_read(mp3dec_ex_t *dec, mp3d_sample_t *buf, size_t samples);
#ifndef MINIMP3_NO_STDIO
/* stdio versions with file pre-load */
int mp3dec_load(mp3dec_t *dec, const char *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_iterate(const char *file_name, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_ex_open(mp3dec_ex_t *dec, const char *file_name, int seek_method);
#endif

#ifdef __cplusplus
}
#endif
#endif /*MINIMP3_EXT_H*/

#ifdef MINIMP3_IMPLEMENTATION
#include <limits.h>

static void mp3dec_skip_id3(const uint8_t **pbuf, size_t *pbuf_size)
{
    char *buf = (char *)(*pbuf);
    size_t buf_size = *pbuf_size;
#ifndef MINIMP3_NOSKIP_ID3V2
    if (buf_size > 10 && !memcmp(buf, "ID3", 3) && !((buf[5] & 15) || (buf[6] & 0x80) || (buf[7] & 0x80) || (buf[8] & 0x80) || (buf[9] & 0x80)))
    {
        size_t id3v2size = (((buf[6] & 0x7f) << 21) | ((buf[7] & 0x7f) << 14) | ((buf[8] & 0x7f) << 7) | (buf[9] & 0x7f)) + 10;
        if ((buf[5] & 16))
            id3v2size += 10; /* footer */
        if (id3v2size >= buf_size)
            id3v2size = buf_size;
        buf      += id3v2size;
        buf_size -= id3v2size;
    }
#endif
#ifndef MINIMP3_NOSKIP_ID3V1
    if (buf_size > 128 && !memcmp(buf + buf_size - 128, "TAG", 3))
    {
        buf_size -= 128;
        if (buf_size > 227 && !memcmp(buf + buf_size - 227, "TAG+", 4))
            buf_size -= 227;
    }
#endif
#ifndef MINIMP3_NOSKIP_APEV2
    if (buf_size > 32 && !memcmp(buf + buf_size - 32, "APETAGEX", 8))
    {
        buf_size -= 32;
    }
#endif
    *pbuf = (const uint8_t *)buf;
    *pbuf_size = buf_size;
}

static int mp3dec_check_vbrtag(const uint8_t *frame, int frame_size, uint32_t *frames, int *delay, int *padding)
{
    int i;
    static const char g_xing_tag[4] = { 'X', 'i', 'n', 'g' };
    static const char g_info_tag[4] = { 'I', 'n', 'f', 'o' };
#define FRAMES_FLAG     1
#define BYTES_FLAG      2
#define TOC_FLAG        4
#define VBR_SCALE_FLAG  8
    /* TODO: skip side-info?
    /  Side info offsets afrer header:
    /                Mono  Stereo
    /  MPEG1          17     32
    /  MPEG2 & 2.5     9     17*/
    for (i = 5; i < frame_size - 36; i++)
    {
        const uint8_t *tag = frame + i;
        if (memcmp(g_xing_tag, tag, 4) && memcmp(g_info_tag, tag, 4))
            continue;
        int flags = tag[7];
        if (!((flags & FRAMES_FLAG)))
            break;
        tag += 8;
        (*frames) = (uint32_t)(tag[0] << 24) | (tag[1] << 16) | (tag[2] << 8) | tag[3];
        tag += 4;
        if (flags & BYTES_FLAG)
            tag += 4;
        if (flags & TOC_FLAG)
            tag += 100;
        if (flags & VBR_SCALE_FLAG)
            tag += 4;
        tag += 21;
        if (tag - frame + 2 >= frame_size)
            break;
        *delay   = ((tag[0] << 4) | (tag[1] >> 4)) + (528 + 1);
        *padding = (((tag[1] & 0xF) << 8) | tag[2]) - (528 + 1);
        return 1;
    }
    return 0;
}

void mp3dec_load_buf(mp3dec_t *dec, const uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data)
{
    uint64_t detected_samples = 0;
    size_t orig_buf_size = buf_size;
    int to_skip = 0;
    mp3dec_frame_info_t frame_info;
    memset(info, 0, sizeof(*info));
    memset(&frame_info, 0, sizeof(frame_info));
    /* skip id3 */
    mp3dec_skip_id3(&buf, &buf_size);
    if (!buf_size)
        return;
    /* try to make allocation size assumption by first frame or vbr tag */
    mp3dec_init(dec);
    int samples;
    do
    {
        uint32_t frames;
        int delay, padding, free_format_bytes = 0, frame_size = 0;
        int i = mp3d_find_frame(buf, buf_size, &free_format_bytes, &frame_size);
        buf      += i;
        buf_size -= i;
        if (i && !frame_size)
            continue;
        if (!frame_size)
            return;
        const uint8_t *hdr = buf;
        frame_info.channels = HDR_IS_MONO(hdr) ? 1 : 2;
        frame_info.hz = hdr_sample_rate_hz(hdr);
        frame_info.layer = 4 - HDR_GET_LAYER(hdr);
        frame_info.bitrate_kbps = hdr_bitrate_kbps(hdr);
        frame_info.frame_bytes = frame_size;
        samples = hdr_frame_samples(hdr)*frame_info.channels;
        if (mp3dec_check_vbrtag(hdr, frame_size, &frames, &delay, &padding))
        {
            padding *= frame_info.channels;
            to_skip = delay*frame_info.channels;
            detected_samples = samples*(uint64_t)frames;
            if (detected_samples >= (uint64_t)to_skip)
                detected_samples -= to_skip;
            if (padding > 0 && detected_samples >= (uint64_t)padding)
                detected_samples -= padding;
            if (!detected_samples)
                return;
            buf      += frame_size;
            buf_size -= frame_size;
        }
        break;
    } while(1);
    size_t allocated = MINIMP3_MAX_SAMPLES_PER_FRAME*sizeof(mp3d_sample_t);
    if (detected_samples)
        allocated += detected_samples*sizeof(mp3d_sample_t);
    else
        allocated += (buf_size/frame_info.frame_bytes)*samples*sizeof(mp3d_sample_t);
    info->buffer = (mp3d_sample_t*)malloc(allocated);
    if (!info->buffer)
        return;
    /* save info */
    info->channels = frame_info.channels;
    info->hz       = frame_info.hz;
    info->layer    = frame_info.layer;
    /* decode all frames */
    size_t avg_bitrate_kbps = 0, frames = 0;
    int frame_bytes;
    do
    {
        if ((allocated - info->samples*sizeof(mp3d_sample_t)) < MINIMP3_MAX_SAMPLES_PER_FRAME*sizeof(mp3d_sample_t))
        {
            allocated *= 2;
            info->buffer = (mp3d_sample_t*)realloc(info->buffer, allocated);
        }
        samples = mp3dec_decode_frame(dec, buf, MINIMP3_MIN(buf_size, (size_t)INT_MAX), info->buffer + info->samples, &frame_info);
        frame_bytes = frame_info.frame_bytes;
        buf      += frame_bytes;
        buf_size -= frame_bytes;
        if (samples)
        {
            if (info->hz != frame_info.hz || info->layer != frame_info.layer)
                break;
            if (info->channels && info->channels != frame_info.channels)
#ifdef MINIMP3_ALLOW_MONO_STEREO_TRANSITION
                info->channels = 0; /* mark file with mono-stereo transition */
#else
                break;
#endif
            samples *= frame_info.channels;
            if (to_skip)
            {
                size_t skip = MINIMP3_MIN(samples, to_skip);
                to_skip -= skip;
                samples -= skip;
                memmove(info->buffer, info->buffer + skip, samples);
            }
            info->samples += samples;
            avg_bitrate_kbps += frame_info.bitrate_kbps;
            frames++;
            if (progress_cb)
                progress_cb(user_data, orig_buf_size, orig_buf_size - buf_size, &frame_info);
        }
    } while (frame_bytes);
    if (detected_samples)
        info->samples = detected_samples;
    /* reallocate to normal buffer size */
    if (allocated != info->samples*sizeof(mp3d_sample_t))
        info->buffer = (mp3d_sample_t*)realloc(info->buffer, info->samples*sizeof(mp3d_sample_t));
    if (frames)
        info->avg_bitrate_kbps = avg_bitrate_kbps/frames;
}

size_t mp3dec_iterate_buf(const uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data)
{
    size_t frames = 0;
    const uint8_t *orig_buf = buf;
    /* skip id3 */
    mp3dec_skip_id3(&buf, &buf_size);
    if (!buf_size)
        return 0;
    mp3dec_frame_info_t frame_info;
    memset(&frame_info, 0, sizeof(frame_info));
    do
    {
        int free_format_bytes = 0, frame_size = 0;
        int i = mp3d_find_frame(buf, buf_size, &free_format_bytes, &frame_size);
        buf      += i;
        buf_size -= i;
        if (i && !frame_size)
            continue;
        if (!frame_size)
            break;
        const uint8_t *hdr = buf;
        frame_info.channels = HDR_IS_MONO(hdr) ? 1 : 2;
        frame_info.hz = hdr_sample_rate_hz(hdr);
        frame_info.layer = 4 - HDR_GET_LAYER(hdr);
        frame_info.bitrate_kbps = hdr_bitrate_kbps(hdr);
        frame_info.frame_bytes = frame_size;

        frames++;
        if (callback)
        {
            if (callback(user_data, hdr, frame_size, free_format_bytes, buf_size, hdr - orig_buf, &frame_info))
                break;
        }
        buf      += frame_size;
        buf_size -= frame_size;
    } while (1);
    return frames;
}

static int mp3dec_load_index(void *user_data, const uint8_t *frame, int frame_size, int free_format_bytes, size_t buf_size, size_t offset, mp3dec_frame_info_t *info)
{
    mp3dec_frame_t *idx_frame;
    mp3dec_ex_t *dec = (mp3dec_ex_t *)user_data;
    if (!dec->index.frames && !dec->vbr_tag_found)
    {   /* detect VBR tag and try to avoid full scan */
        uint32_t frames;
        int delay, padding;
        dec->info = *info;
        dec->start_offset = dec->offset = offset;
        dec->end_offset   = offset + buf_size;
        dec->free_format_bytes = free_format_bytes; /* should not change */
        if (mp3dec_check_vbrtag(frame, frame_size, &frames, &delay, &padding))
        {
            padding *= info->channels;
            dec->start_delay = dec->to_skip = delay*info->channels;
            dec->samples = hdr_frame_samples(frame)*info->channels*(uint64_t)frames;
            if (dec->samples >= (uint64_t)dec->start_delay)
                dec->samples -= dec->start_delay;
            if (padding > 0 && dec->samples >= (uint64_t)padding)
                dec->samples -= padding;
            dec->detected_samples = dec->samples;
            dec->start_offset = dec->offset = offset + frame_size;
            dec->vbr_tag_found = 1;
            return 1;
        }
    }
    if (dec->index.num_frames + 1 > dec->index.capacity)
    {
        if (!dec->index.capacity)
            dec->index.capacity = 4096;
        else
            dec->index.capacity *= 2;
        dec->index.frames = (mp3dec_frame_t *)realloc((void*)dec->index.frames, sizeof(mp3dec_frame_t)*dec->index.capacity);
        if (!dec->index.frames)
            return MP3D_E_MEMORY;
    }
    idx_frame = &dec->index.frames[dec->index.num_frames++];
    idx_frame->offset = offset;
    idx_frame->sample = dec->samples;
    if (!dec->buffer_samples && dec->index.num_frames < 256)
    {   /* for some cutted mp3 frames, bit-reservoir not filled and decoding can't be started from first frames */
        /* try to decode up to 255 first frames till samples starts to decode */
        dec->buffer_samples = mp3dec_decode_frame(&dec->mp3d, frame, MINIMP3_MIN(buf_size, (size_t)INT_MAX), dec->buffer, info);
        dec->samples += dec->buffer_samples*info->channels;
    } else
        dec->samples += hdr_frame_samples(frame)*info->channels;
    return 0;
}

int mp3dec_ex_open_buf(mp3dec_ex_t *dec, const uint8_t *buf, size_t buf_size, int seek_method)
{
    memset(dec, 0, sizeof(*dec));
    dec->file.buffer = buf;
    dec->file.size   = buf_size;
    dec->seek_method = seek_method;
    mp3dec_init(&dec->mp3d);
    if (MP3D_SEEK_TO_SAMPLE == dec->seek_method)
    {
        if (mp3dec_iterate_buf(dec->file.buffer, dec->file.size, mp3dec_load_index, dec) > 0 && !dec->index.frames && !dec->vbr_tag_found)
            return MP3D_E_MEMORY;
        mp3dec_init(&dec->mp3d);
        dec->buffer_samples = 0;
    }
    return 0;
}

#ifndef MINIMP3_SEEK_IDX_LINEAR_SEARCH
static size_t mp3dec_idx_binary_search(mp3dec_index_t *idx, uint64_t position)
{
    size_t end = idx->num_frames, start = 0, index = 0;
    while (start <= end)
    {
        size_t mid = (start + end) / 2;
        if (idx->frames[mid].sample >= position)
        {   /* move left side. */
            if (idx->frames[mid].sample == position)
                return mid;
            end = mid - 1;
        }  else
        {   /* move to right side */
            index = mid;
            start = mid + 1;
            if (start == idx->num_frames)
                break;
        }
    }
    return index;
}
#endif

int mp3dec_ex_seek(mp3dec_ex_t *dec, uint64_t position)
{
    size_t i;
    if (MP3D_SEEK_TO_BYTE == dec->seek_method)
    {
        dec->offset = position;
        return 0;
    }
    position += dec->start_delay;
    if (0 == position)
    {   /* optimize seek to zero, no index needed */
seek_zero:
        dec->offset  = dec->start_offset;
        dec->to_skip = 0;
        goto do_exit;
    }
    if (!dec->index.frames && dec->vbr_tag_found)
    {   /* no index created yet (vbr tag used to calculate track length) */
        dec->samples = 0;
        dec->buffer_samples = 0;
        if (mp3dec_iterate_buf(dec->file.buffer + dec->start_offset, dec->file.size - dec->start_offset, mp3dec_load_index, dec) > 0 && !dec->index.frames)
            return MP3D_E_MEMORY;
        for (i = 0; i < dec->index.num_frames; i++)
            dec->index.frames[i].offset += dec->start_offset;
        dec->samples = dec->detected_samples;
    }
    if (!dec->index.frames)
        goto seek_zero; /* no frames in file - seek to zero */
#ifdef MINIMP3_SEEK_IDX_LINEAR_SEARCH
    for (i = 0; i < dec->index.num_frames; i++)
    {
        if (dec->index.frames[i].sample >= position)
            break;
    }
#else
    i = mp3dec_idx_binary_search(&dec->index, position);
#endif
    if (i)
    {
        int to_fill_bytes = 511;
        int skip_frames = MINIMP3_PREDECODE_FRAMES
#ifdef MINIMP3_SEEK_IDX_LINEAR_SEARCH
         + ((dec->index.frames[i].sample == position) ? 0 : 1)
#endif
        ;
        i -= MINIMP3_MIN(i, (size_t)skip_frames);
        if (3 == dec->info.layer)
        {
            while (i && to_fill_bytes)
            {   /* make sure bit-reservoir is filled when we start decoding */
                bs_t bs[1];
                L3_gr_info_t gr_info[4];
                const uint8_t *hdr = dec->file.buffer + dec->index.frames[i - 1].offset;
                int frame_bytes, frame_size = hdr_frame_bytes(hdr, dec->free_format_bytes) + hdr_padding(hdr);
                bs_init(bs, hdr + HDR_SIZE, frame_size - HDR_SIZE);
                if (HDR_IS_CRC(hdr))
                    get_bits(bs, 16);
                i--;
                if (L3_read_side_info(bs, gr_info, hdr) < 0)
                    break; /* frame not decodable, we can start from here */
                frame_bytes = (bs->limit - bs->pos)/8;
                to_fill_bytes -= MINIMP3_MIN(to_fill_bytes, frame_bytes);
            }
        }
    }
    dec->offset = dec->index.frames[i].offset;
    dec->to_skip = position - dec->index.frames[i].sample;
    while ((i + 1) < dec->index.num_frames && !dec->index.frames[i].sample && !dec->index.frames[i + 1].sample)
    {   /* skip not decodable first frames */
        const uint8_t *hdr = dec->file.buffer + dec->index.frames[i].offset;
        dec->to_skip += hdr_frame_samples(hdr)*dec->info.channels;
        i++;
    }
do_exit:
    dec->buffer_samples  = 0;
    dec->buffer_consumed = 0;
    mp3dec_init(&dec->mp3d);
    return 0;
}

size_t mp3dec_ex_read(mp3dec_ex_t *dec, mp3d_sample_t *buf, size_t samples)
{
    uint64_t end_offset = dec->end_offset ? dec->end_offset : dec->file.size;
    size_t samples_requested = samples;
    mp3dec_frame_info_t frame_info;
    memset(&frame_info, 0, sizeof(frame_info));
    if (dec->buffer_consumed < dec->buffer_samples)
    {
        size_t to_copy = MINIMP3_MIN((size_t)(dec->buffer_samples - dec->buffer_consumed), samples);
        memcpy(buf, dec->buffer + dec->buffer_consumed, to_copy*sizeof(mp3d_sample_t));
        buf += to_copy;
        dec->buffer_consumed += to_copy;
        samples -= to_copy;
    }
    while (samples)
    {
        const uint8_t *dec_buf = dec->file.buffer + dec->offset;
        uint64_t buf_size = end_offset - dec->offset;
        if (!buf_size)
            break;
        dec->buffer_samples = mp3dec_decode_frame(&dec->mp3d, dec_buf, MINIMP3_MIN(buf_size, (uint64_t)INT_MAX), dec->buffer, &frame_info);
        dec->buffer_consumed = 0;
        if (dec->buffer_samples)
        {
            dec->buffer_samples *= frame_info.channels;
            if (dec->to_skip)
            {
                size_t skip = MINIMP3_MIN(dec->buffer_samples, dec->to_skip);
                dec->buffer_consumed += skip;
                dec->to_skip -= skip;
            }
            size_t to_copy = MINIMP3_MIN((size_t)(dec->buffer_samples - dec->buffer_consumed), samples);
            memcpy(buf, dec->buffer + dec->buffer_consumed, to_copy*sizeof(mp3d_sample_t));
            buf += to_copy;
            dec->buffer_consumed += to_copy;
            samples -= to_copy;
        } else if (dec->to_skip)
        {   /* In mp3 decoding not always can start decode from any frame because of bit reservoir,
               count skip samples for such frames */
            int frame_samples = hdr_frame_samples(dec_buf)*frame_info.channels;
            dec->to_skip -= MINIMP3_MIN(frame_samples, dec->to_skip);
        }
        dec->offset += frame_info.frame_bytes;
    }
    return samples_requested - samples;
}

#ifndef MINIMP3_NO_STDIO

#if defined(__linux__) || defined(__FreeBSD__)
#include <errno.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#if !defined(_GNU_SOURCE)
#include <sys/ipc.h>
#include <sys/shm.h>
#endif
#if !defined(MAP_POPULATE) && defined(__linux__)
#define MAP_POPULATE 0x08000
#elif !defined(MAP_POPULATE)
#define MAP_POPULATE 0
#endif

static void mp3dec_close_file(mp3dec_map_info_t *map_info)
{
    if (map_info->buffer && MAP_FAILED != map_info->buffer)
        munmap((void *)map_info->buffer, map_info->size);
    map_info->buffer = 0;
    map_info->size   = 0;
}

static int mp3dec_open_file(const char *file_name, mp3dec_map_info_t *map_info)
{
    int file;
    struct stat st;
    memset(map_info, 0, sizeof(*map_info));
retry_open:
    file = open(file_name, O_RDONLY);
    if (file < 0 && (errno == EAGAIN || errno == EINTR))
        goto retry_open;
    if (file < 0 || fstat(file, &st) < 0)
    {
        close(file);
        return -1;
    }

    map_info->size = st.st_size;
retry_mmap:
    map_info->buffer = (const uint8_t *)mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE | MAP_POPULATE, file, 0);
    if (MAP_FAILED == map_info->buffer && (errno == EAGAIN || errno == EINTR))
        goto retry_mmap;
    close(file);
    if (MAP_FAILED == map_info->buffer)
        return -1;
    return 0;
}

static void mp3dec_close_ring(mp3dec_map_info_t *map_info)
{
#if defined(__linux__) && defined(_GNU_SOURCE)
    if (map_info->buffer && MAP_FAILED != map_info->buffer)
        munmap((void *)map_info->buffer, map_info->size*2);
#esle
    if (map_info->buffer)
    {
        shmdt(map_info->buffer);
        shmdt(map_info->buffer + map_info->size);
    }
#endif
    map_info->buffer = 0;
    map_info->size   = 0;
}

static int mp3dec_open_ring(mp3dec_map_info_t *map_info, size_t size)
{
    int memfd, page_size;
#if defined(__linux__) && defined(_GNU_SOURCE)
    int res;
#endif
    memset(map_info, 0, sizeof(*map_info));

#ifdef _SC_PAGESIZE
    page_size = sysconf( _SC_PAGESIZE );
#else
    page_size = getpagesize();
#endif
    map_info->size = (size + page_size - 1)/page_size*page_size;

#if defined(__linux__) && defined(_GNU_SOURCE)
    memfd = memfd_create("mp3_ring", 0);
    if (memfd < 0)
        return -1;

retry_ftruncate:
    res = ftruncate(memfd, size);
    if (res && (errno == EAGAIN || errno == EINTR))
        goto retry_ftruncate;
    if (res)
        goto error;

retry_mmap:
    map_info->buffer = (const uint8_t *)mmap(NULL, map_info->size*2, PROT_NONE, MAP_PRIVATE, -1, 0);
    if (MAP_FAILED == map_info->buffer && (errno == EAGAIN || errno == EINTR))
        goto retry_mmap;
    if (MAP_FAILED == map_info->buffer)
        goto error;
retry_mmap2:
    map_info->buffer = (const uint8_t *)mmap((void *)map_info->buffer, map_info->size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, memfd, 0);
    if (MAP_FAILED == map_info->buffer && (errno == EAGAIN || errno == EINTR))
        goto retry_mmap2;
    if (MAP_FAILED == map_info->buffer)
        goto error;
retry_mmap3:
    map_info->buffer = (const uint8_t *)mmap((void *)map_info->buffer + map_info->size, map_info->size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, memfd, 0);
    if (MAP_FAILED == map_info->buffer && (errno == EAGAIN || errno == EINTR))
        goto retry_mmap3;
    if (MAP_FAILED == map_info->buffer)
        goto error;

    close(memfd);
    return 0;
error:
    close(memfd);
    mp3dec_close_ring(map_info);
    return -1;
#else
    memfd = shmget(IPC_PRIVATE, map_info->size, IPC_CREAT | 0700);
    if (memfd < 0)
        return -1;
retry_mmap:
    map_info->buffer = (const uint8_t *)mmap(NULL, map_info->size*2, PROT_NONE, MAP_PRIVATE, -1, 0);
    if (MAP_FAILED == map_info->buffer && (errno == EAGAIN || errno == EINTR))
        goto retry_mmap;
    if (MAP_FAILED == map_info->buffer)
        goto error;
    if (map_info->buffer != shmat(memfd, map_info->buffer, 0))
        goto error;
    if ((map_info->buffer + map_info->size) != shmat(memfd, map_info->buffer + map_info->size, 0))
        goto error;
    if (shmctl(memfd, IPC_RMID, NULL) < 0)
        return -1;
    return 0;
error:
    shmctl(memfd, IPC_RMID, NULL);
    mp3dec_close_ring(map_info);
    return -1;
#endif
}
#elif defined(_WIN32)
#include <windows.h>

static void mp3dec_close_file(mp3dec_map_info_t *map_info)
{
    if (map_info->buffer)
        UnmapViewOfFile(map_info->buffer);
    map_info->buffer = 0;
    map_info->size   = 0;
}

static int mp3dec_open_file(const char *file_name, mp3dec_map_info_t *map_info)
{
    memset(map_info, 0, sizeof(*map_info));

    HANDLE mapping = NULL;
    HANDLE file = CreateFileA(file_name, GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
    if (INVALID_HANDLE_VALUE == file)
        return -1;
    LARGE_INTEGER s;
    s.LowPart = GetFileSize(file, (DWORD*)&s.HighPart);
    if (s.LowPart == INVALID_FILE_SIZE && GetLastError() != NO_ERROR)
        goto error;
    map_info->size = s.QuadPart;

    mapping = CreateFileMapping(file, NULL, PAGE_READONLY, 0, 0, NULL);
    if (!mapping)
        goto error;
    map_info->buffer = (const uint8_t*)MapViewOfFile(mapping, FILE_MAP_READ, 0, 0, s.QuadPart);
    CloseHandle(mapping);
    if (!map_info->buffer)
        goto error;

    CloseHandle(file);
    return 0;
error:
    mp3dec_close_file(map_info);
    CloseHandle(file);
    return -1;
}

static void mp3dec_close_ring(mp3dec_map_info_t *map_info)
{
    if (map_info->buffer)
    {
        UnmapViewOfFile(map_info->buffer);
        UnmapViewOfFile(map_info->buffer + map_info->size);
    }
    map_info->buffer = 0;
    map_info->size   = 0;
}

static int mp3dec_open_ring(mp3dec_map_info_t *map_info, size_t size)
{
    map_info->size = size;
    HANDLE hMap = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, size, NULL);
    if (INVALID_HANDLE_VALUE == hMap)
        return -1;
    map_info->buffer = (const uint8_t *)VirtualAlloc(0, size*2, MEM_RESERVE, PAGE_READWRITE);
    if (!map_info->buffer)
        goto error;
    if (!MapViewOfFileEx(hMap, FILE_MAP_ALL_ACCESS, 0, 0, size, (LPVOID)map_info->buffer))
        goto error;
    if (!MapViewOfFileEx(hMap, FILE_MAP_ALL_ACCESS, 0, 0, size, (LPVOID)(map_info->buffer + size)))
        goto error;
    CloseHandle(hMap);
    return 0;
error:
    mp3dec_close_ring(map_info);
    CloseHandle(hMap);
    return -1;
}
#else
#include <stdio.h>
#define MINIMP3_NO_RING

static void mp3dec_close_file(mp3dec_map_info_t *map_info)
{
    if (map_info->buffer)
        free((void *)map_info->buffer);
    map_info->buffer = 0;
    map_info->size = 0;
}

static int mp3dec_open_file(const char *file_name, mp3dec_map_info_t *map_info)
{
    memset(map_info, 0, sizeof(*map_info));
    FILE *file = fopen(file_name, "rb");
    if (!file)
        return -1;
    long size = -1;
    if (fseek(file, 0, SEEK_END))
        goto error;
    size = ftell(file);
    if (size < 0)
        goto error;
    map_info->size = (size_t)size;
    if (fseek(file, 0, SEEK_SET))
        goto error;
    map_info->buffer = (uint8_t *)malloc(map_info->size);
    if (!map_info->buffer)
        goto error;
    if (fread((void *)map_info->buffer, 1, map_info->size, file) != map_info->size)
        goto error;
    fclose(file);
    return 0;
error:
    mp3dec_close_file(map_info);
    fclose(file);
    return -1;
}
#endif

int mp3dec_load(mp3dec_t *dec, const char *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data)
{
    int ret;
    mp3dec_map_info_t map_info;
    if ((ret = mp3dec_open_file(file_name, &map_info)))
        return ret;
    mp3dec_load_buf(dec, map_info.buffer, map_info.size, info, progress_cb, user_data);
    mp3dec_close_file(&map_info);
    return info->samples ? 0 : -1;
}

int mp3dec_iterate(const char *file_name, MP3D_ITERATE_CB callback, void *user_data)
{
    int ret;
    mp3dec_map_info_t map_info;
    if ((ret = mp3dec_open_file(file_name, &map_info)))
        return ret;
    mp3dec_iterate_buf(map_info.buffer, map_info.size, callback, user_data);
    mp3dec_close_file(&map_info);
    return 0;
}

void mp3dec_ex_close(mp3dec_ex_t *dec)
{
    if (dec->is_file)
        mp3dec_close_file(&dec->file);
    if (dec->index.frames)
        free(dec->index.frames);
    memset(dec, 0, sizeof(*dec));
}

int mp3dec_ex_open(mp3dec_ex_t *dec, const char *file_name, int seek_method)
{
    int ret;
    if ((ret = mp3dec_open_file(file_name, &dec->file)))
        return ret;
    ret = mp3dec_ex_open_buf(dec, dec->file.buffer, dec->file.size, seek_method);
    dec->is_file = 1;
    return ret;
}

int mp3dec_ex_open_cb(mp3dec_ex_t *dec, MP3D_READ_CB read_cb, void *read_user_data, MP3D_SEEK_CB seek_cb, void *seek_user_data, int seek_method)
{
    memset(dec, 0, sizeof(*dec));
#ifndef MINIMP3_NO_RING
    mp3dec_open_ring(&dec->file, MINIMP3_RING_SIZE);
#endif
    dec->seek_method = seek_method;
    mp3dec_init(&dec->mp3d);
    /* TODO */
    (void)read_cb;
    (void)read_user_data;
    (void)seek_cb;
    (void)seek_user_data;
    return 0;
}
#else /* MINIMP3_NO_STDIO */
void mp3dec_ex_close(mp3dec_ex_t *dec)
{
    if (dec->index.frames)
        free(dec->index.frames);
    memset(dec, 0, sizeof(*dec));
}
#endif

#endif /*MINIMP3_IMPLEMENTATION*/