71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
package meta
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import (
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"encoding/binary"
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"fmt"
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"strings"
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)
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// VorbisComment contains a list of name-value pairs.
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//
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// ref: https://www.xiph.org/flac/format.html#metadata_block_vorbis_comment
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type VorbisComment struct {
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// Vendor name.
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Vendor string
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// A list of tags, each represented by a name-value pair.
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Tags [][2]string
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}
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// parseVorbisComment reads and parses the body of a VorbisComment metadata
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// block.
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func (block *Block) parseVorbisComment() (err error) {
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// 32 bits: vendor length.
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var x uint32
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if err = binary.Read(block.lr, binary.LittleEndian, &x); err != nil {
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return unexpected(err)
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}
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// (vendor length) bits: Vendor.
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buf, err := readBytes(block.lr, int(x))
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if err != nil {
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return unexpected(err)
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}
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comment := new(VorbisComment)
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block.Body = comment
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comment.Vendor = string(buf)
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// Parse tags.
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// 32 bits: number of tags.
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if err = binary.Read(block.lr, binary.LittleEndian, &x); err != nil {
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return unexpected(err)
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}
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if x < 1 {
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return nil
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}
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comment.Tags = make([][2]string, x)
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for i := range comment.Tags {
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// 32 bits: vector length
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if err = binary.Read(block.lr, binary.LittleEndian, &x); err != nil {
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return unexpected(err)
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}
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// (vector length): vector.
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buf, err = readBytes(block.lr, int(x))
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if err != nil {
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return unexpected(err)
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}
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vector := string(buf)
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// Parse tag, which has the following format:
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// NAME=VALUE
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pos := strings.Index(vector, "=")
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if pos == -1 {
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return fmt.Errorf("meta.Block.parseVorbisComment: unable to locate '=' in vector %q", vector)
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}
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comment.Tags[i][0] = vector[:pos]
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comment.Tags[i][1] = vector[pos+1:]
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}
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return nil
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}
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