mirror of
https://github.com/wader/fq.git
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1ddea1ada3
Move registry to interp and add support for functions and filesystems. This will be used later for allow formats to add own functions and fq code. Add gojqextra function helpers to have more comfortable API to add functions. Takes care of argument type casting and JQValue:s and some more things. Refactor interp package to use new function helper and registry. Probably fixes a bunch of JQValue bugs and other type errors. Refactor out some mpeg nal things to mpeg format. Refactor interp jq code into display.q and init.jq. Remove undocumented aes_ctr funciton, was a test. Hopefully will add more crypto things laster.
126 lines
3.0 KiB
Go
126 lines
3.0 KiB
Go
package mp3
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// TODO: vbri
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import (
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"fmt"
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"github.com/wader/fq/format"
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"github.com/wader/fq/pkg/decode"
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"github.com/wader/fq/pkg/interp"
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)
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var headerFormat decode.Group
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var footerFormat decode.Group
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var mp3Frame decode.Group
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func init() {
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interp.RegisterFormat(decode.Format{
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Name: format.MP3,
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ProbeOrder: 20, // after most others (silent samples and jpeg header can look like mp3 sync)
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Description: "MP3 file",
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Groups: []string{format.PROBE},
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DecodeFn: mp3Decode,
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DecodeInArg: format.Mp3In{
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MaxUniqueHeaderConfigs: 5,
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MaxSyncSeek: 4 * 1024 * 8,
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},
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Dependencies: []decode.Dependency{
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{Names: []string{format.ID3V2}, Group: &headerFormat},
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{
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Names: []string{
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format.ID3V1,
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format.ID3V11,
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format.APEV2,
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},
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Group: &footerFormat,
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},
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{Names: []string{format.MP3_FRAME}, Group: &mp3Frame},
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},
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})
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}
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func mp3Decode(d *decode.D, in any) any {
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mi, _ := in.(format.Mp3In)
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// things in a mp3 stream usually have few unique combinations of.
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// does not include bitrate on purpose
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type headerConfig struct {
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MPEGVersion int
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ProtectionAbsent bool
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SampleRate int
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ChannelsIndex int
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ChannelModeIndex int
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}
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uniqueHeaderConfigs := map[headerConfig]struct{}{}
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// there are mp3s files in the wild with multiple headers, two id3v2 tags etc
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d.FieldArray("headers", func(d *decode.D) {
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for d.NotEnd() {
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if dv, _, _ := d.TryFieldFormat("header", headerFormat, nil); dv == nil {
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return
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}
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}
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})
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lastValidEnd := int64(0)
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validFrames := 0
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decodeFailures := 0
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d.FieldArray("frames", func(d *decode.D) {
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for d.NotEnd() {
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syncLen, _, err := d.TryPeekFind(16, 8, int64(mi.MaxSyncSeek), func(v uint64) bool {
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return (v&0b1111_1111_1110_0000 == 0b1111_1111_1110_0000 && // sync header
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v&0b0000_0000_0001_1000 != 0b0000_0000_0000_1000 && // not reserved mpeg version
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v&0b0000_0000_0000_0110 == 0b0000_0000_0000_0010) // layer 3
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})
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if err != nil || syncLen < 0 {
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break
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}
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if syncLen > 0 {
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d.SeekRel(syncLen)
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}
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dv, v, _ := d.TryFieldFormat("frame", mp3Frame, nil)
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if dv == nil {
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decodeFailures++
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d.SeekRel(8)
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continue
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}
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mfo, ok := v.(format.MP3FrameOut)
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if !ok {
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panic(fmt.Sprintf("expected MP3FrameOut got %#+v", v))
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}
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uniqueHeaderConfigs[headerConfig{
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MPEGVersion: mfo.MPEGVersion,
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ProtectionAbsent: mfo.ProtectionAbsent,
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SampleRate: mfo.SampleRate,
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ChannelsIndex: mfo.ChannelsIndex,
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ChannelModeIndex: mfo.ChannelModeIndex,
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}] = struct{}{}
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lastValidEnd = d.Pos()
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validFrames++
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if len(uniqueHeaderConfigs) >= mi.MaxUniqueHeaderConfigs {
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d.Errorf("too many unique header configurations")
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}
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}
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})
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if validFrames == 0 || (validFrames < 2 && decodeFailures > 0) {
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d.Errorf("no frames found")
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}
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d.SeekAbs(lastValidEnd)
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d.FieldArray("footers", func(d *decode.D) {
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for d.NotEnd() {
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if dv, _, _ := d.TryFieldFormat("footer", footerFormat, nil); dv == nil {
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return
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}
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}
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})
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return nil
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}
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