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package magic
import (
"bytes"
"encoding/binary"
)
var (
// Flac matches a Free Lossless Audio Codec file.
Flac = prefix([]byte("\x66\x4C\x61\x43\x00\x00\x00\x22"))
// Midi matches a Musical Instrument Digital Interface file.
Midi = prefix([]byte("\x4D\x54\x68\x64"))
// Ape matches a Monkey's Audio file.
Ape = prefix([]byte("\x4D\x41\x43\x20\x96\x0F\x00\x00\x34\x00\x00\x00\x18\x00\x00\x00\x90\xE3"))
// MusePack matches a Musepack file.
MusePack = prefix([]byte("MPCK"))
// Au matches a Sun Microsystems au file.
Au = prefix([]byte("\x2E\x73\x6E\x64"))
// Amr matches an Adaptive Multi-Rate file.
Amr = prefix([]byte("\x23\x21\x41\x4D\x52"))
// Voc matches a Creative Voice file.
Voc = prefix([]byte("Creative Voice File"))
// M3u matches a Playlist file.
M3u = prefix([]byte("#EXTM3U"))
// AAC matches an Advanced Audio Coding file.
AAC = prefix([]byte{0xFF, 0xF1}, []byte{0xFF, 0xF9})
)
// Mp3 matches an mp3 file.
func Mp3(raw []byte, limit uint32) bool {
if len(raw) < 3 {
return false
}
if bytes.HasPrefix(raw, []byte("ID3")) {
// MP3s with an ID3v2 tag will start with "ID3"
// ID3v1 tags, however appear at the end of the file.
return true
}
// Match MP3 files without tags
switch binary.BigEndian.Uint16(raw[:2]) & 0xFFFE {
case 0xFFFA:
// MPEG ADTS, layer III, v1
return true
case 0xFFF2:
// MPEG ADTS, layer III, v2
return true
case 0xFFE2:
// MPEG ADTS, layer III, v2.5
return true
}
return false
}
// Wav matches a Waveform Audio File Format file.
func Wav(raw []byte, limit uint32) bool {
return len(raw) > 12 &&
bytes.Equal(raw[:4], []byte("RIFF")) &&
bytes.Equal(raw[8:12], []byte{0x57, 0x41, 0x56, 0x45})
}
// Aiff matches Audio Interchange File Format file.
func Aiff(raw []byte, limit uint32) bool {
return len(raw) > 12 &&
bytes.Equal(raw[:4], []byte{0x46, 0x4F, 0x52, 0x4D}) &&
bytes.Equal(raw[8:12], []byte{0x41, 0x49, 0x46, 0x46})
}
// Qcp matches a Qualcomm Pure Voice file.
func Qcp(raw []byte, limit uint32) bool {
return len(raw) > 12 &&
bytes.Equal(raw[:4], []byte("RIFF")) &&
bytes.Equal(raw[8:12], []byte("QLCM"))
}
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