013424077b
Also update package webp to use package riff. LGTM=r R=r CC=golang-codereviews, pascal.massimino https://golang.org/cl/162850043
114 lines
2.2 KiB
Go
114 lines
2.2 KiB
Go
// Copyright 2014 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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package riff_test
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import (
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"strings"
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"code.google.com/p/go.image/riff"
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)
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func ExampleReader() {
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formType, r, err := riff.NewReader(strings.NewReader(data))
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if err != nil {
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log.Fatal(err)
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}
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fmt.Printf("RIFF(%s)\n", formType)
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if err := dump(r, ".\t"); err != nil {
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log.Fatal(err)
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}
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// Output:
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// RIFF(ROOT)
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// . ZERO ""
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// . ONE "a"
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// . LIST(META)
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// . . LIST(GOOD)
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// . . . ONE "a"
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// . . . FIVE "klmno"
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// . . ZERO ""
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// . . LIST(BAD )
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// . . . THRE "def"
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// . TWO "bc"
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// . LIST(UGLY)
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// . . FOUR "ghij"
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// . . SIX "pqrstu"
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}
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func dump(r *riff.Reader, indent string) error {
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for {
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chunkID, chunkLen, chunkData, err := r.Next()
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if err == io.EOF {
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return nil
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}
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if err != nil {
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return err
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}
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if chunkID == riff.LIST {
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listType, list, err := riff.NewListReader(chunkLen, chunkData)
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if err != nil {
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return err
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}
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fmt.Printf("%sLIST(%s)\n", indent, listType)
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if err := dump(list, indent+".\t"); err != nil {
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return err
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}
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continue
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}
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b, err := ioutil.ReadAll(chunkData)
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if err != nil {
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return err
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}
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fmt.Printf("%s%s %q\n", indent, chunkID, b)
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}
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}
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func encodeU32(u uint32) string {
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return string([]byte{
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byte(u >> 0),
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byte(u >> 8),
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byte(u >> 16),
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byte(u >> 24),
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})
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}
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func encode(chunkID, contents string) string {
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n := len(contents)
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if n&1 == 1 {
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contents += "\x00"
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}
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return chunkID + encodeU32(uint32(n)) + contents
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}
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func encodeMulti(typ0, typ1 string, chunks ...string) string {
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n := 4
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for _, c := range chunks {
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n += len(c)
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}
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s := typ0 + encodeU32(uint32(n)) + typ1
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for _, c := range chunks {
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s += c
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}
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return s
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}
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var (
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d0 = encode("ZERO", "")
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d1 = encode("ONE ", "a")
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d2 = encode("TWO ", "bc")
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d3 = encode("THRE", "def")
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d4 = encode("FOUR", "ghij")
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d5 = encode("FIVE", "klmno")
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d6 = encode("SIX ", "pqrstu")
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l0 = encodeMulti("LIST", "GOOD", d1, d5)
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l1 = encodeMulti("LIST", "BAD ", d3)
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l2 = encodeMulti("LIST", "UGLY", d4, d6)
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l01 = encodeMulti("LIST", "META", l0, d0, l1)
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data = encodeMulti("RIFF", "ROOT", d0, d1, l01, d2, l2)
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)
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