vgmstream/src/meta/bcstm.c

#include "meta.h"
#include "../util.h"

/* BCSTM - Nintendo 3DS format */
VGMSTREAM * init_vgmstream_bcstm(STREAMFILE *streamFile) {
    VGMSTREAM * vgmstream = NULL;
    coding_t coding_type;

    off_t info_offset = 0, seek_offset = 0, data_offset = 0;
    uint16_t temp_id;
    int codec_number;
    int channel_count, loop_flag;
    int i, ima = 0;
    off_t start_offset;
    int section_count;

    /* check extension, case insensitive */
    if ( !check_extensions(streamFile,"bcstm") )
        goto fail;

    /* check header */
    if ((uint32_t)read_32bitBE(0, streamFile) != 0x4353544D) /* "CSTM" */
        goto fail;

    if ((uint16_t)read_16bitLE(4, streamFile) != 0xFEFF)
        goto fail;

    section_count = read_16bitLE(0x10, streamFile);
    for (i = 0; i < section_count; i++) {
        temp_id = read_16bitLE(0x14 + i * 0xc, streamFile);
        switch(temp_id) {
            case 0x4000:
                info_offset = read_32bitLE(0x18 + i * 0xc, streamFile);
                /* size_t info_size = read_32bitLE(0x1c + i * 0xc, streamFile); */
                break;
            case 0x4001:
                seek_offset = read_32bitLE(0x18 + i * 0xc, streamFile);
                /* size_t seek_size = read_32bitLE(0x1c + i * 0xc, streamFile); */
                break;
            case 0x4002:
                data_offset = read_32bitLE(0x18 + i * 0xc, streamFile);
                /* size_t data_size = read_32bitLE(0x1c + i * 0xc, streamFile); */
                break;
            case 0x4003:
                /* off_t regn_offset = read_32bitLE(0x18 + i * 0xc, streamFile); */
                /* size_t regn_size = read_32bitLE(0x1c + i * 0xc, streamFile); */
                break;
            case 0x4004:
                /* off_t pdat_offset = read_32bitLE(0x18 + i * 0xc, streamFile); */
                /* size_t pdat_size = read_32bitLE(0x1c + i * 0xc, streamFile); */
                break;
            default:
                break;
        }
    }

    if (info_offset == 0) goto fail;
    if ((uint32_t)read_32bitBE(info_offset, streamFile) != 0x494E464F) /* "INFO" */
        goto fail;


    /* check type details */
    codec_number = read_8bit(info_offset + 0x20, streamFile);
    loop_flag = read_8bit(info_offset + 0x21, streamFile);
    channel_count = read_8bit(info_offset + 0x22, streamFile);

    switch (codec_number) {
    case 0:
        coding_type = coding_PCM8;
        break;
    case 1:
        coding_type = coding_PCM16LE;
        break;
    case 2:
        if (seek_offset == 0) goto fail;
        if ((uint32_t)read_32bitBE(seek_offset, streamFile) != 0x5345454B) { /* "SEEK" If this header doesn't exist, assuming that the file is IMA */
            ima = 1;
            coding_type = coding_3DS_IMA;
        }
        else
            coding_type = coding_NGC_DSP;
        break;
    default:
        goto fail;
    }

    if (channel_count < 1) goto fail;

    /* build the VGMSTREAM */
    vgmstream = allocate_vgmstream(channel_count, loop_flag);
    if (!vgmstream) goto fail;

    /* fill in the vital statistics */
    vgmstream->num_samples = read_32bitLE(info_offset + 0x2c, streamFile);
    vgmstream->sample_rate = read_32bitLE(info_offset + 0x24, streamFile);
    /* channels and loop flag are set by allocate_vgmstream */
    if (ima) //Shift the loop points back slightly to avoid stupid pops in some IMA streams due to DC offsetting
    {
        vgmstream->loop_start_sample = read_32bitLE(info_offset + 0x28, streamFile);
        if (vgmstream->loop_start_sample > 10000)
        {
            vgmstream->loop_start_sample -= 5000;
            vgmstream->loop_end_sample = vgmstream->num_samples - 5000;
        }
        else
            vgmstream->loop_end_sample = vgmstream->num_samples;
    }
    else
    {
        vgmstream->loop_start_sample = read_32bitLE(info_offset + 0x28, streamFile);
        vgmstream->loop_end_sample = vgmstream->num_samples;
    }

    vgmstream->coding_type = coding_type;
    if (channel_count == 1)
        vgmstream->layout_type = layout_none;
    else
    {
        if (ima)
            vgmstream->layout_type = layout_interleave;
        else
            vgmstream->layout_type = layout_interleave_shortblock;
    }
    vgmstream->meta_type = meta_CSTM;

    if (ima)
        vgmstream->interleave_block_size = 0x200;
    else {
        vgmstream->interleave_block_size = read_32bitLE(info_offset + 0x34, streamFile);
        vgmstream->interleave_smallblock_size = read_32bitLE(info_offset + 0x44, streamFile);
    }

    if (vgmstream->coding_type == coding_NGC_DSP) {
        off_t coef_offset;
        off_t tempoffset = info_offset;
        int foundcoef = 0;
        int i, j;
        int coef_spacing = 0x2E;

        while (!(foundcoef))
        {
            if ((uint32_t)read_32bitLE(tempoffset, streamFile) == 0x00004102)
            {
                coef_offset = read_32bitLE(tempoffset + 4, streamFile) + tempoffset + (channel_count * 8) - 4 - info_offset;
                foundcoef++;
                break;
            }
            tempoffset++;
        }

        for (j = 0; j<vgmstream->channels; j++) {
            for (i = 0; i<16; i++) {
                vgmstream->ch[j].adpcm_coef[i] = read_16bitLE(info_offset + coef_offset + j*coef_spacing + i * 2, streamFile);
            }
        }
    }

    if (ima) { // No SEEK (ADPC) header, so just start where the SEEK header is supposed to be.
        if (seek_offset == 0) goto fail;
        start_offset = seek_offset;
    } else {
        if (data_offset == 0) goto fail;
        start_offset = data_offset + 0x20;
    }


    /* open the file for reading by each channel */
    if (!vgmstream_open_stream(vgmstream,streamFile,start_offset))
        goto fail;

    return vgmstream;

fail:
    close_vgmstream(vgmstream);
    return NULL;
}