#include <FLAC/all.h>
#include <string.h>

// compile with:
// gcc -O2 -S -o test.s test.c

typedef struct {
    FLAC__bool has_md5sum;
} DecoderSession;

void callback1(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data) {
    DecoderSession *decoder_session = (DecoderSession*)client_data;
    decoder_session->has_md5sum = memcmp(metadata->data.stream_info.md5sum, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16);
}

void callback2(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data) {
    DecoderSession *decoder_session = (DecoderSession*)client_data;
    decoder_session->has_md5sum = memcmp(metadata->data.stream_info.md5sum, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16) != 0;
}

void callback3(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data) {
    DecoderSession *decoder_session = (DecoderSession*)client_data;
    FLAC__byte emptyMD5[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    decoder_session->has_md5sum = memcmp(metadata->data.stream_info.md5sum, emptyMD5, 16);
}