-
Notifications
You must be signed in to change notification settings - Fork 14
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
7 changed files
with
458 additions
and
21 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,158 @@ | ||
| // Copyright 2019 The ebml-go authors. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| package ebml | ||
|
|
||
| import ( | ||
| "errors" | ||
| "io" | ||
| ) | ||
|
|
||
| var ( | ||
| errFixedLaceUndivisible = errors.New("undivisible fixed lace") | ||
| ) | ||
|
|
||
| // Unlacer is the interface to read laced frames in Block. | ||
| type Unlacer interface { | ||
| Read() ([]byte, error) | ||
| } | ||
|
|
||
| type unlacer struct { | ||
| r io.Reader | ||
| i int | ||
| size []int | ||
| } | ||
|
|
||
| func (u *unlacer) Read() ([]byte, error) { | ||
| if u.i >= len(u.size) { | ||
| return nil, io.EOF | ||
| } | ||
| n := u.size[u.i] | ||
| u.i++ | ||
|
|
||
| b := make([]byte, n) | ||
| _, err := io.ReadFull(u.r, b) | ||
| return b, err | ||
| } | ||
|
|
||
| // NewNoUnlacer creates pass-through Unlacer for not laced data. | ||
| func NewNoUnlacer(r io.Reader, n uint64) (Unlacer, error) { | ||
| return &unlacer{r: r, size: []int{int(n)}}, nil | ||
| } | ||
|
|
||
| // NewXiphUnlacer creates Unlacer for Xiph laced data. | ||
| func NewXiphUnlacer(r io.Reader, n uint64) (Unlacer, error) { | ||
| var nFrame int | ||
| var b [1]byte | ||
| switch _, err := io.ReadFull(r, b[:]); err { | ||
| case nil: | ||
| nFrame = int(b[0]) + 1 | ||
| case io.EOF: | ||
| return nil, io.ErrUnexpectedEOF | ||
| default: | ||
| return nil, err | ||
| } | ||
| n-- | ||
|
|
||
| ul := &unlacer{ | ||
| r: r, | ||
| size: make([]int, nFrame), | ||
| } | ||
| for i := 0; i < nFrame-1; i++ { | ||
| for { | ||
| var b [1]byte | ||
| switch _, err := io.ReadFull(ul.r, b[:]); err { | ||
| case nil: | ||
| case io.EOF: | ||
| return nil, io.ErrUnexpectedEOF | ||
| default: | ||
| return nil, err | ||
| } | ||
| n-- | ||
| ul.size[i] += int(b[0]) | ||
| if b[0] != 0xFF { | ||
| ul.size[nFrame-1] -= ul.size[i] | ||
| break | ||
| } | ||
| } | ||
| } | ||
| ul.size[nFrame-1] += int(n) | ||
| if ul.size[nFrame-1] <= 0 { | ||
| return nil, io.ErrUnexpectedEOF | ||
| } | ||
|
|
||
| return ul, nil | ||
| } | ||
|
|
||
| // NewFixedUnlacer creates Unlacer for Fixed laced data. | ||
| func NewFixedUnlacer(r io.Reader, n uint64) (Unlacer, error) { | ||
| var nFrame int | ||
| var b [1]byte | ||
| switch _, err := io.ReadFull(r, b[:]); err { | ||
| case nil: | ||
| nFrame = int(b[0]) + 1 | ||
| case io.EOF: | ||
| return nil, io.ErrUnexpectedEOF | ||
| default: | ||
| return nil, err | ||
| } | ||
|
|
||
| ul := &unlacer{ | ||
| r: r, | ||
| size: make([]int, nFrame), | ||
| } | ||
| ul.size[0] = (int(n) - 1) / nFrame | ||
| for i := 1; i < nFrame; i++ { | ||
| ul.size[i] = ul.size[0] | ||
| } | ||
| if ul.size[0]*nFrame+1 != int(n) { | ||
| return nil, errFixedLaceUndivisible | ||
| } | ||
| return ul, nil | ||
| } | ||
|
|
||
| // NewEBMLUnlacer creates Unlacer for EBML laced data. | ||
| func NewEBMLUnlacer(r io.Reader, n uint64) (Unlacer, error) { | ||
| var nFrame int | ||
| var b [1]byte | ||
| switch _, err := io.ReadFull(r, b[:]); err { | ||
| case nil: | ||
| nFrame = int(b[0]) + 1 | ||
| case io.EOF: | ||
| return nil, io.ErrUnexpectedEOF | ||
| default: | ||
| return nil, err | ||
| } | ||
| n-- | ||
|
|
||
| ul := &unlacer{ | ||
| r: r, | ||
| size: make([]int, nFrame), | ||
| } | ||
| for i := 0; i < nFrame-1; i++ { | ||
| n64, nRead, err := readVInt(ul.r) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| n -= uint64(nRead) | ||
| ul.size[i] = int(n64) | ||
| ul.size[nFrame-1] -= int(n64) | ||
| } | ||
| ul.size[nFrame-1] += int(n) | ||
| if ul.size[nFrame-1] <= 0 { | ||
| return nil, io.ErrUnexpectedEOF | ||
| } | ||
|
|
||
| return ul, nil | ||
| } |
Oops, something went wrong.