121 lines
2.9 KiB
Go
121 lines
2.9 KiB
Go
package meta
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import (
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"encoding/binary"
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"io"
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)
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// Picture contains the image data of an embedded picture.
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//
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// ref: https://www.xiph.org/flac/format.html#metadata_block_picture
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type Picture struct {
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// Picture type according to the ID3v2 APIC frame:
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//
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// 0: Other
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// 1: 32x32 pixels 'file icon' (PNG only)
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// 2: Other file icon
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// 3: Cover (front)
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// 4: Cover (back)
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// 5: Leaflet page
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// 6: Media (e.g. label side of CD)
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// 7: Lead artist/lead performer/soloist
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// 8: Artist/performer
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// 9: Conductor
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// 10: Band/Orchestra
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// 11: Composer
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// 12: Lyricist/text writer
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// 13: Recording Location
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// 14: During recording
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// 15: During performance
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// 16: Movie/video screen capture
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// 17: A bright coloured fish
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// 18: Illustration
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// 19: Band/artist logotype
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// 20: Publisher/Studio logotype
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//
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// ref: http://id3.org/id3v2.4.0-frames
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Type uint32
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// MIME type string. The MIME type "-->" specifies that the picture data is
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// to be interpreted as an URL instead of image data.
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MIME string
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// Description of the picture.
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Desc string
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// Image dimensions.
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Width, Height uint32
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// Color depth in bits-per-pixel.
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Depth uint32
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// Number of colors in palette; 0 for non-indexed images.
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NPalColors uint32
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// Image data.
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Data []byte
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}
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// parsePicture reads and parses the body of a Picture metadata block.
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func (block *Block) parsePicture() error {
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// 32 bits: Type.
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pic := new(Picture)
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block.Body = pic
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err := binary.Read(block.lr, binary.BigEndian, &pic.Type)
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if err != nil {
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return unexpected(err)
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}
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// 32 bits: (MIME type length).
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var x uint32
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if err = binary.Read(block.lr, binary.BigEndian, &x); err != nil {
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return unexpected(err)
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}
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// (MIME type length) bytes: MIME.
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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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pic.MIME = string(buf)
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// 32 bits: (description length).
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if err = binary.Read(block.lr, binary.BigEndian, &x); err != nil {
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return unexpected(err)
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}
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// (description length) bytes: Desc.
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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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pic.Desc = string(buf)
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// 32 bits: Width.
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if err = binary.Read(block.lr, binary.BigEndian, &pic.Width); err != nil {
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return unexpected(err)
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}
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// 32 bits: Height.
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if err = binary.Read(block.lr, binary.BigEndian, &pic.Height); err != nil {
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return unexpected(err)
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}
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// 32 bits: Depth.
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if err = binary.Read(block.lr, binary.BigEndian, &pic.Depth); err != nil {
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return unexpected(err)
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}
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// 32 bits: NPalColors.
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if err = binary.Read(block.lr, binary.BigEndian, &pic.NPalColors); err != nil {
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return unexpected(err)
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}
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// 32 bits: (data length).
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if err = binary.Read(block.lr, binary.BigEndian, &x); err != nil {
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return unexpected(err)
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}
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if x == 0 {
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return nil
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}
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// (data length) bytes: Data.
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pic.Data = make([]byte, x)
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_, err = io.ReadFull(block.lr, pic.Data)
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return unexpected(err)
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}
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