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Remove non-relative Seek calls from all functions.

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Previously we would seek to the beginning of the io.ReadSeeker. It is much more
flexible to assume that the caller passes the ReadSeeker in an appropriate state.
This commit is contained in:
David Howden
2015-06-07 12:58:58 +10:00
parent 7f8f21cc46
commit 6df4e78d96
6 changed files with 15 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files
sum.go
+7 -25
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@@ -17,6 +17,11 @@ func Sum(r io.ReadSeeker) (string, error) {
return "", err
}
_, err = r.Seek(-11, os.SEEK_CUR)
if err != nil {
return "", fmt.Errorf("could not seek back to original position: %v", err)
}
if string(b[4:11]) == "ftypM4A" {
return SumAtoms(r)
}
@@ -35,13 +40,8 @@ func Sum(r io.ReadSeeker) (string, error) {
return h, nil
}
// SumAll returns a checksum of the entire content.
// SumAll returns a checksum of the content from the reader (until EOF).
func SumAll(r io.ReadSeeker) (string, error) {
_, err := r.Seek(0, os.SEEK_SET)
if err != nil {
return "", fmt.Errorf("error seeking to 0: %v", err)
}
b, err := ioutil.ReadAll(r)
if err != nil {
return "", nil
@@ -52,14 +52,6 @@ func SumAll(r io.ReadSeeker) (string, error) {
// SumAtoms constructs a checksum of MP4 audio file data provided by the io.ReadSeeker which is
// metadata invariant.
func SumAtoms(r io.ReadSeeker) (string, error) {
_, err := r.Seek(0, os.SEEK_SET)
if err != nil {
return "", fmt.Errorf("error seeking to 0: %v", err)
}
return sumAtoms(r)
}
func sumAtoms(r io.ReadSeeker) (string, error) {
for {
var size uint32
err := binary.Read(r, binary.BigEndian, &size)
@@ -85,7 +77,7 @@ func sumAtoms(r io.ReadSeeker) (string, error) {
fallthrough
case "moov", "udta", "ilst":
return sumAtoms(r)
return SumAtoms(r)
case "free":
_, err = r.Seek(int64(size-8), os.SEEK_CUR)
@@ -112,11 +104,6 @@ func sumAtoms(r io.ReadSeeker) (string, error) {
// SumID3v1 constructs a checksum of MP3 audio file data (assumed to have ID3v1 tags) provided
// by the io.ReadSeeker which is metadata invariant.
func SumID3v1(r io.ReadSeeker) (string, error) {
_, err := r.Seek(0, os.SEEK_SET)
if err != nil {
return "", fmt.Errorf("error seeking to 0: %v", err)
}
b, err := ioutil.ReadAll(r)
if err != nil {
return "", err
@@ -131,11 +118,6 @@ func SumID3v1(r io.ReadSeeker) (string, error) {
// SumID3v2 constructs a checksum of MP3 audio file data (assumed to have ID3v2 tags) provided by the
// io.ReadSeeker which is metadata invariant.
func SumID3v2(r io.ReadSeeker) (string, error) {
_, err := r.Seek(0, os.SEEK_SET)
if err != nil {
return "", fmt.Errorf("error seeking to 0: %v", err)
}
h, err := readID3v2Header(r)
if err != nil {
return "", fmt.Errorf("error reading ID3v2 header: %v", err)