Method find_string

RemoteIDModule/romfs.cpp:79–131

decompress and return a string */

  decompress and return a string
*/
const char *ROMFS::find_string(const char *name)
{
    const auto *f = find(name);
    if (!f) {
        return nullptr;
    }

    // last 4 bytes of gzip file are length of decompressed data
    const uint8_t *p = &f->contents[f->size-4];
    uint32_t decompressed_size = p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
    
    uint8_t *decompressed_data = (uint8_t *)malloc(decompressed_size + 1);
    if (!decompressed_data) {
        return nullptr;
    }

    // explicitly null terimnate the data
    decompressed_data[decompressed_size] = 0;

    TINF_DATA *d = (TINF_DATA *)malloc(sizeof(TINF_DATA));
    if (!d) {
        ::free(decompressed_data);
        return nullptr;
    }
    uzlib_uncompress_init(d, NULL, 0);

    d->source = f->contents;
    d->source_limit = f->contents + f->size - 4;

    // assume gzip format
    int res = uzlib_gzip_parse_header(d);
    if (res != TINF_OK) {
        ::free(decompressed_data);
        ::free(d);
        return nullptr;
    }

    d->dest = decompressed_data;
    d->destSize = decompressed_size;

    // we don't check CRC, as it just wastes flash space for constant
    // ROMFS data
    res = uzlib_uncompress(d);

    ::free(d);
    
    if (res != TINF_OK) {
        ::free(decompressed_data);
        return nullptr;
    }

    return (const char *)decompressed_data;
}