mirror of
https://github.com/imgproxy/imgproxy.git
synced 2024-11-24 08:12:38 +02:00
107 lines
2.2 KiB
Go
107 lines
2.2 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Original code was cropped and fixed by @DarthSim for imgproxy needs
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package imagemeta
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import (
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"errors"
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"io"
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"github.com/imgproxy/imgproxy/v3/imagetype"
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"golang.org/x/image/riff"
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"golang.org/x/image/vp8"
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"golang.org/x/image/vp8l"
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)
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var ErrWebpInvalidFormat = errors.New("webp: invalid format")
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var (
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webpFccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
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webpFccVP8 = riff.FourCC{'V', 'P', '8', ' '}
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webpFccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
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webpFccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
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webpFccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
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)
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func DecodeWebpMeta(r io.Reader) (Meta, error) {
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formType, riffReader, err := riff.NewReader(r)
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if err != nil {
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return nil, err
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}
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if formType != webpFccWEBP {
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return nil, ErrWebpInvalidFormat
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}
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var buf [10]byte
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for {
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chunkID, chunkLen, chunkData, err := riffReader.Next()
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if err == io.EOF {
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err = ErrWebpInvalidFormat
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}
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if err != nil {
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return nil, err
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}
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switch chunkID {
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case webpFccALPH:
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// Ignore
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case webpFccVP8:
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if int32(chunkLen) < 0 {
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return nil, ErrWebpInvalidFormat
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}
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d := vp8.NewDecoder()
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d.Init(chunkData, int(chunkLen))
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fh, err := d.DecodeFrameHeader()
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return &meta{
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format: imagetype.WEBP,
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width: fh.Width,
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height: fh.Height,
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}, err
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case webpFccVP8L:
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conf, err := vp8l.DecodeConfig(chunkData)
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if err != nil {
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return nil, err
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}
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return &meta{
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format: imagetype.WEBP,
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width: conf.Width,
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height: conf.Height,
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}, nil
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case webpFccVP8X:
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if chunkLen != 10 {
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return nil, ErrWebpInvalidFormat
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}
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if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
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return nil, err
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}
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widthMinusOne := uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
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heightMinusOne := uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
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return &meta{
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format: imagetype.WEBP,
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width: int(widthMinusOne) + 1,
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height: int(heightMinusOne) + 1,
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}, nil
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default:
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return nil, ErrWebpInvalidFormat
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}
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}
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}
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func init() {
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RegisterFormat("RIFF????WEBPVP8", DecodeWebpMeta)
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}
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