ARMSX1/psx/dev/cdrom/disc.c

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>

#include "disc.h"
#include "cue.h"
#include "chd.h"
#include "../../log.h"

#define MSF_TO_LBA(m, s, f) ((m * 4500) + (s * 75) + f)

const char* disc_cd_extensions[] = {
    "cue",
    "bin",
    "iso",
#ifdef USE_CHD
    "chd",
#endif
    0
};

typedef struct {
    FILE* file;
    uint32_t sector_size;
    uint32_t sector_count;
} raw_disc_t;

static int raw_read(void* udata, uint32_t lba, void* buf) {
    raw_disc_t* raw = (raw_disc_t*)udata;

    if (!raw || !raw->file)
        return 0;

    if (lba >= raw->sector_count)
        return 0;

    if (fseek(raw->file, (long long)lba * raw->sector_size, SEEK_SET))
        return 0;

    size_t to_read = raw->sector_size;
    memset(buf, 0, CD_SECTOR_SIZE);

    return fread(buf, 1, to_read, raw->file) == to_read ? TS_DATA : 0;
}

static int raw_query(void* udata, uint32_t lba) {
    raw_disc_t* raw = (raw_disc_t*)udata;

    return (raw && (lba < raw->sector_count)) ? TS_DATA : TS_FAR;
}

static int raw_get_track_number(void* udata, uint32_t lba) {
    (void)udata; (void)lba;
    return 1;
}

static int raw_get_track_count(void* udata) {
    (void)udata;
    return 1;
}

static uint32_t raw_get_track_lba(void* udata, int track) {
    (void)udata; (void)track;
    return 0;
}

static void raw_destroy(void* udata) {
    raw_disc_t* raw = (raw_disc_t*)udata;

    if (raw && raw->file)
        fclose(raw->file);

    free(raw);
}

psx_disc_t* psx_disc_create(void) {
    psx_disc_t* disc = malloc(sizeof(psx_disc_t));

    if (disc)
        memset(disc, 0, sizeof(psx_disc_t));

    return disc;
}

int disc_get_extension(const char* path) {
    char ext[16];
    const char* ptr;
    size_t len;
    int i = 0;

    if (!path || !path[0])
        return CD_EXT_UNSUPPORTED;

    ptr = strrchr(path, '.');
    if (!ptr || !ptr[1])
        return CD_EXT_UNSUPPORTED;

    len = strlen(ptr + 1);
    if (len >= sizeof(ext))
        return CD_EXT_UNSUPPORTED;

    for (size_t index = 0; index < len; ++index)
        ext[index] = (char)tolower((unsigned char)ptr[1 + index]);
    ext[len] = '\0';

    while (disc_cd_extensions[i]) {
        if (!strcmp(ext, disc_cd_extensions[i]))
            return i;
        
        ++i;
    }

    return CD_EXT_UNSUPPORTED;
}

int disc_get_cd_type(psx_disc_t* disc) {
    char buf[CD_SECTOR_SIZE];

    // If the disc is smaller than 16 sectors
    // then it can't be a PlayStation game.
    // Audio discs should also have ISO volume
    // descriptors, so it's probably something else
    // entirely.
    if (!psx_disc_read(disc, MSF_TO_LBA(0, 2, 16), buf))
        return CDT_UNKNOWN;

    // Check for the "PLAYSTATION" string at PVD offset 20h
    // Patch 20 byte so comparison is done correctly
    buf[0x2b] = 0;

    if (strncmp(&buf[0x20], "PLAYSTATION", 12))
        return CDT_AUDIO;

    return CDT_LICENSED;
}

int psx_disc_open(psx_disc_t* disc, const char* path) {
    if (!path)
        return CDT_ERROR;

    int ext = disc_get_extension(path);

    return psx_disc_open_as(disc, path, ext);
}

int psx_disc_open_as(psx_disc_t* disc, const char* path, int type) {
    switch (type) {
        case CD_EXT_CUE: {
            cue_t* cue = cue_create();

            cue_init(cue);
            cue_init_disc(cue, disc);

            if (cue_parse(cue, path))
                return CDT_ERROR;

            if (cue_load(cue, LD_FILE))
                return CDT_ERROR;
        } break;

        case CD_EXT_BIN:
        case CD_EXT_ISO: {
            FILE* f = fopen(path, "rb");

            if (!f)
                return CDT_ERROR;

            fseek(f, 0, SEEK_END);
            long long size = ftell(f);
            fseek(f, 0, SEEK_SET);

            raw_disc_t* raw = (raw_disc_t*)malloc(sizeof(raw_disc_t));

            raw->file = f;
            raw->sector_size = (type == CD_EXT_BIN) ? CD_SECTOR_SIZE : 2048;
            raw->sector_count = (uint32_t)(size / raw->sector_size);

            disc->udata = raw;
            disc->read_sector = raw_read;
            disc->query_sector = raw_query;
            disc->get_track_number = raw_get_track_number;
            disc->get_track_count = raw_get_track_count;
            disc->get_track_lba = raw_get_track_lba;
            disc->destroy = raw_destroy;
        } break;

#ifdef USE_CHD
        case CD_EXT_CHD: {
            chd_t* chd = chd_create();

            chd_init(chd);

            if (chd_load(chd, path)) {
                chd_destroy(chd);

                return CDT_ERROR;
            }

            disc->udata = chd;
            disc->read_sector = (read_sector_func)chd_read_sector;
            disc->query_sector = (query_sector_func)chd_query;
            disc->get_track_number = (get_track_number_func)chd_get_track_number;
            disc->get_track_count = (get_track_count_func)chd_get_track_count;
            disc->get_track_lba = (get_track_lba_func)chd_get_track_lba;
            disc->read_subchannel_q = (read_subchannel_q_func)chd_read_subchannel_q;
            disc->destroy = (destroy_func)chd_destroy;
        } break;
#endif

        default:
            return CDT_ERROR;
    }

    if (!disc->read_sector) {
        log_error("Unsupported or failed to open disc image: %s", path);
        return CDT_ERROR;
    }

    return disc_get_cd_type(disc);
}

int psx_disc_read(psx_disc_t* disc, uint32_t lba, void* buf) {
    if (!disc->read_sector)
        return 0;

    return disc->read_sector(disc->udata, lba, buf);
}

int psx_disc_query(psx_disc_t* disc, uint32_t lba) {
    return disc->query_sector(disc->udata, lba);
}

int psx_disc_get_track_number(psx_disc_t* disc, uint32_t lba) {
    return disc->get_track_number(disc->udata, lba);
}

int psx_disc_get_track_count(psx_disc_t* disc) {
    return disc->get_track_count(disc->udata);
}

int psx_disc_get_track_lba(psx_disc_t* disc, int track) {
    return disc->get_track_lba(disc->udata, track);
}

int psx_disc_read_subchannel_q(psx_disc_t* disc, uint32_t lba, uint8_t q[12]) {
    if (!disc || !disc->read_subchannel_q || !q)
        return 0;

    return disc->read_subchannel_q(disc->udata, lba, q);
}

void psx_disc_destroy(psx_disc_t* disc) {
    disc->destroy(disc->udata);

    free(disc);
}