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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package riff_test
import (
"fmt"
"io"
"io/ioutil"
"log"
"strings"
"golang.org/x/image/riff"
)
func ExampleReader() {
formType, r, err := riff.NewReader(strings.NewReader(data))
if err != nil {
log.Fatal(err)
}
fmt.Printf("RIFF(%s)\n", formType)
if err := dump(r, ".\t"); err != nil {
log.Fatal(err)
}
// Output:
// RIFF(ROOT)
// . ZERO ""
// . ONE "a"
// . LIST(META)
// . . LIST(GOOD)
// . . . ONE "a"
// . . . FIVE "klmno"
// . . ZERO ""
// . . LIST(BAD )
// . . . THRE "def"
// . TWO "bc"
// . LIST(UGLY)
// . . FOUR "ghij"
// . . SIX "pqrstu"
}
func dump(r *riff.Reader, indent string) error {
for {
chunkID, chunkLen, chunkData, err := r.Next()
if err == io.EOF {
return nil
}
if err != nil {
return err
}
if chunkID == riff.LIST {
listType, list, err := riff.NewListReader(chunkLen, chunkData)
if err != nil {
return err
}
fmt.Printf("%sLIST(%s)\n", indent, listType)
if err := dump(list, indent+".\t"); err != nil {
return err
}
continue
}
b, err := ioutil.ReadAll(chunkData)
if err != nil {
return err
}
fmt.Printf("%s%s %q\n", indent, chunkID, b)
}
}
func encodeU32(u uint32) string {
return string([]byte{
byte(u >> 0),
byte(u >> 8),
byte(u >> 16),
byte(u >> 24),
})
}
func encode(chunkID, contents string) string {
n := len(contents)
if n&1 == 1 {
contents += "\x00"
}
return chunkID + encodeU32(uint32(n)) + contents
}
func encodeMulti(typ0, typ1 string, chunks ...string) string {
n := 4
for _, c := range chunks {
n += len(c)
}
s := typ0 + encodeU32(uint32(n)) + typ1
for _, c := range chunks {
s += c
}
return s
}
var (
d0 = encode("ZERO", "")
d1 = encode("ONE ", "a")
d2 = encode("TWO ", "bc")
d3 = encode("THRE", "def")
d4 = encode("FOUR", "ghij")
d5 = encode("FIVE", "klmno")
d6 = encode("SIX ", "pqrstu")
l0 = encodeMulti("LIST", "GOOD", d1, d5)
l1 = encodeMulti("LIST", "BAD ", d3)
l2 = encodeMulti("LIST", "UGLY", d4, d6)
l01 = encodeMulti("LIST", "META", l0, d0, l1)
data = encodeMulti("RIFF", "ROOT", d0, d1, l01, d2, l2)
)
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