bool midi_file_write(const midi & m, const char * fn) {
ofstream out(fn, ios_base::out | ios_base::binary);
if (out.fail()) return false;
printHeader(m, out);
int lengths[m.trackCount()];
uint16_t ff = getFileFormat(m);
if (m.trackCount()) {
lengths[0] = writeTrack(m.tracks(0), out, m.getTicksPerQuaterNote(), true);
for (unsigned i = 1; i < m.trackCount(); ++i) {
if (ff < 2)
lengths[i] = writeTrack(m.tracks(i), out);
else
lengths[i] = writeTrack(m.tracks(i), out, m.getTicksPerQuaterNote(), true);
}
}
out.seekp(14, ios_base::beg);
for (unsigned i = 0; i < m.trackCount(); ++i) {
out.seekp(4, ios_base::cur);
printUint32_t(lengths[i] - 8, out);
out.seekp(lengths[i] - 8, ios_base::cur);
}
out.close();
return out.fail();
}
void printHeader(const midi& m, ostream &out) {
out.write("MThd\0\0\0\6", 8);
if (m.trackCount() == 0)
throw "No tracks! Cannot save a file.";
else if (m.trackCount() == 1)
printUint16_t(1, out);
else {
printUint16_t(getFileFormat(m), out);
}
printUint16_t(m.trackCount(), out);
printUint16_t((uint16_t) m.getTicksPerQuaterNote(), out);
}
