org.apache.flex.swf.io

Class SWFReader

java.lang.Object

org.apache.flex.swf.io.SWFReader

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<ITag>, ISWFReader, ITagContainer

public class SWFReader
extends Object
implements ISWFReader, ITagContainer

Implementation of ISWFReader. This is a recursive-descent decoder of a SWF file. Error handling for malformed SWFs: 1. Catch RuntimeExceptions thrown by InputBitStream and report problems. 2. Handle errors in SWF tag bodies by logging problems and throwing MalformedTagExceptions. 3. Recover from #1 and #2 by throwing out the current tag and reading up to the start of the next tag.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	SWFReader.TagHeader Wrapper class for "type" and "length" field in a SWF tag header.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	BITS_TAG_LENGTH The lower 6 bits in the TagCodeAndLength field in the SWF tag header is the tag length.
protected InputBitStream	bitStream SWF input bit stream.
static org.apache.flex.swf.io.SWFReader.InvalidTag	INVALID_TAG
protected static int	MASK_TAG_LENGTH Mask on the TagCodeAndLength field to get the lower 6 bits of tag length.
protected Collection<ICompilerProblem>	problems
protected SWF	swf Model of the SWF file.
protected List<ITag>	tags All the tags in the SWF file.

Constructor Summary

Constructors

Constructor and Description
SWFReader() Create a SWFReader and initialize field members.
SWFReader(boolean isBuildFrames) Create a SWFReader and initialize field members.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the reader an the underlying input stream.
Collection<ICompilerProblem>	getProblems()
ISWF	getSWF() Get the SWF tied to this reader.
Iterator<ITag>	iterator() Get all the tags in this SWF file.
protected SWFReader.TagHeader	nextTagHeader() Read the next tag's header field and get the tag length and type.
DefineMorphShapeTag	readDefineMorphShape()
DefineMorphShape2Tag	readDefineMorphShape2()
protected DoABCTag	readDoABC()
ISWF	readFrom(InputStream input, String path) Read a SWF file from the input stream.
protected boolean	readHeader() Read SWF header.
protected Matrix	readMatrix()
protected ITag	readTag(SWFReader.TagHeader header) Read a tag body.
protected ITag	readTagBody(TagType type) Select the tag decoding function by its type.
protected void	readTags() Read SWF tags and add each tag to the tag list.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INVALID_TAG

public static final org.apache.flex.swf.io.SWFReader.InvalidTag INVALID_TAG

MASK_TAG_LENGTH

protected static final int MASK_TAG_LENGTH

Mask on the TagCodeAndLength field to get the lower 6 bits of tag length.

See Also:

Constant Field Values

BITS_TAG_LENGTH

protected static final int BITS_TAG_LENGTH

The lower 6 bits in the TagCodeAndLength field in the SWF tag header is the tag length.

See Also:

Constant Field Values

bitStream

protected InputBitStream bitStream

SWF input bit stream.

swf

protected SWF swf

Model of the SWF file.

tags

protected final List<ITag> tags

All the tags in the SWF file. The frame building process is based on these tags.

problems

protected final Collection<ICompilerProblem> problems

Constructor Detail

SWFReader

public SWFReader()

Create a SWFReader and initialize field members.

SWFReader

public SWFReader(boolean isBuildFrames)

Create a SWFReader and initialize field members.

Parameters:

isBuildFrames - if true, the reader will build SWF frames from tags read

Method Detail

readFrom

public ISWF readFrom(InputStream input,
            String path)

Description copied from interface: ISWFReader

Read a SWF file from the input stream.

Specified by:

readFrom in interface ISWFReader

Parameters:

input - source.

path - path of input source, used for error reporting. May not be null.

Returns:

SWF model

getSWF

public ISWF getSWF()

Get the SWF tied to this reader. Note that the returned SWF may or not be initialized depending on whether readFrom() has been called or not

Returns:

swf

getProblems

public Collection<ICompilerProblem> getProblems()

Specified by:

getProblems in interface ITagContainer

readTags

protected void readTags()
                 throws IOException

Read SWF tags and add each tag to the tag list. Stop at the End tag.

Throws:

IOException - error

nextTagHeader

protected SWFReader.TagHeader nextTagHeader()

Read the next tag's header field and get the tag length and type.

Returns:

next tag header

readTag

protected ITag readTag(SWFReader.TagHeader header)
                throws IOException

Read a tag body. A "read boundary" is marked to the length of the tag to prevent invalid tag or incorrect decoding logic from contaminating the following tags or having left-over bytes after decoding a tag.

Parameters:

header - tag header

Returns:

tag model or null if the tag is invalid.

Throws:

IOException - error

close

public void close()
           throws IOException

Close the reader an the underlying input stream.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

iterator

public Iterator<ITag> iterator()

Get all the tags in this SWF file.

Specified by:

iterator in interface Iterable<ITag>

readDoABC

protected DoABCTag readDoABC()
                      throws IOException

Throws:

IOException

readHeader

protected boolean readHeader()
                      throws IOException

Read SWF header.

Returns:

true if successful, false if there is an error in the header.

Throws:

IOException

readMatrix

protected Matrix readMatrix()

readDefineMorphShape

public DefineMorphShapeTag readDefineMorphShape()
                                         throws IOException,
                                                org.apache.flex.swf.io.SWFReader.MalformedTagException

Throws:

IOException

org.apache.flex.swf.io.SWFReader.MalformedTagException

See Also:

SWFWriter.writeDefineMorphShape(org.apache.flex.swf.tags.DefineMorphShapeTag)

readDefineMorphShape2

public DefineMorphShape2Tag readDefineMorphShape2()
                                           throws IOException,
                                                  org.apache.flex.swf.io.SWFReader.MalformedTagException

Throws:

IOException

org.apache.flex.swf.io.SWFReader.MalformedTagException

See Also:

SWFWriter.writeDefineMorphShape2(org.apache.flex.swf.tags.DefineMorphShape2Tag)

readTagBody

protected ITag readTagBody(TagType type)
                    throws IOException,
                           org.apache.flex.swf.io.SWFReader.MalformedTagException

Select the tag decoding function by its type.

Parameters:

type - tag type

Returns:

tag model

Throws:

IOException

org.apache.flex.swf.io.SWFReader.MalformedTagException