package com.bumptech.glide.gifdecoder;
/**
* Copyright (c) 2013 Xcellent Creations, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
import android.graphics.Bitmap;
import android.util.Log;
import com.bumptech.glide.Resource;
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.resource.bitmap.BitmapResource;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* Reads frame data from a GIF image source and decodes it into individual frames
* for animation purposes. Image data can be read from either and InputStream source
* or a byte[].
*
* This class is optimized for running animations with the frames, there
* are no methods to get individual frame images, only to decode the next frame in the
* animation sequence. Instead, it lowers its memory footprint by only housing the minimum
* data necessary to decode the next frame in the animation sequence.
*
* The animation must be manually moved forward using {@link #advance()} before requesting the next
* frame. This method must also be called before you request the first frame or an error will
* occur.
*
* Implementation adapted from sample code published in Lyons. (2004). <em>Java for Programmers</em>,
* republished under the MIT Open Source License
*/
public class GifDecoder {
private static final String TAG = GifDecoder.class.getSimpleName();
/**
* File read status: No errors.
*/
public static final int STATUS_OK = 0;
/**
* File read status: Error decoding file (may be partially decoded)
*/
public static final int STATUS_FORMAT_ERROR = 1;
/**
* File read status: Unable to open source.
*/
public static final int STATUS_OPEN_ERROR = 2;
/**
* max decoder pixel stack size
*/
private static final int MAX_STACK_SIZE = 4096;
/**
* GIF Disposal Method meaning take no action
*/
private static final int DISPOSAL_UNSPECIFIED = 0;
/**
* GIF Disposal Method meaning leave canvas from previous frame
*/
private static final int DISPOSAL_NONE = 1;
/**
* GIF Disposal Method meaning clear canvas to background color
*/
private static final int DISPOSAL_BACKGROUND = 2;
/**
* GIF Disposal Method meaning clear canvas to frame before last
*/
private static final int DISPOSAL_PREVIOUS = 3;
//Global File Header values and parsing flags
private int[] act; // active color table
// Raw GIF data from input source
private ByteBuffer rawData;
// Raw data read working array
private byte[] block = new byte[256]; // current data block
// LZW decoder working arrays
private short[] prefix;
private byte[] suffix;
private byte[] pixelStack;
private byte[] mainPixels;
private int[] mainScratch;
private int framePointer = -1;
private BitmapPool bitmapPool;
private Bitmap currentImage;
private byte[] data;
private GifHeader header;
private String id;
public GifDecoder(BitmapPool bitmapPool) {
this.bitmapPool = bitmapPool;
header = new GifHeader();
}
public int getWidth() {
return header.width;
}
public int getHeight() {
return header.height;
}
public boolean isTransparent() {
return header.isTransparent;
}
public int getGifByteSize() {
return data.length;
}
public byte[] getData() {
return data;
}
public int getDecodedFramesByteSizeSum() {
// 4 == ARGB_8888, 2 == RGB_565
return header.frameCount * header.width * header.height * (header.isTransparent ? 4 : 2);
}
/**
* Move the animation frame counter forward
*/
public void advance() {
framePointer = (framePointer + 1) % header.frameCount;
}
/**
* Gets display duration for specified frame.
*
* @param n int index of frame
* @return delay in milliseconds
*/
public int getDelay(int n) {
int delay = -1;
if ((n >= 0) && (n < header.frameCount)) {
delay = header.frames.get(n).delay;
}
return delay;
}
/**
* Gets display duration for the upcoming frame
*/
public int getNextDelay() {
if (header.frameCount <= 0 || framePointer < 0) {
return -1;
}
return getDelay(framePointer);
}
/**
* Gets the number of frames read from file.
*
* @return frame count
*/
public int getFrameCount() {
return header.frameCount;
}
/**
* Gets the current index of the animation frame, or -1 if animation hasn't not yet started
*
* @return frame index
*/
public int getCurrentFrameIndex() {
return framePointer;
}
/**
* Gets the "Netscape" iteration count, if any. A count of 0 means repeat indefinitiely.
*
* @return iteration count if one was specified, else 1.
*/
public int getLoopCount() {
return header.loopCount;
}
public String getId() {
return id;
}
/**
* Get the next frame in the animation sequence.
*
* @return Bitmap representation of frame
*/
public Resource<Bitmap> getNextFrame() {
if (header.frameCount <= 0 || framePointer < 0 ) {
return null;
}
GifFrame frame = header.frames.get(framePointer);
//Set the appropriate color table
if (frame.lct == null) {
act = header.gct;
} else {
act = frame.lct;
if (header.bgIndex == frame.transIndex) {
header.bgColor = 0;
}
}
int save = 0;
if (frame.transparency) {
save = act[frame.transIndex];
act[frame.transIndex] = 0; // set transparent color if specified
}
if (act == null) {
Log.w(TAG, "No Valid Color Table");
header.status = STATUS_FORMAT_ERROR; // no color table defined
return null;
}
Bitmap result = setPixels(framePointer); // transfer pixel data to image
currentImage = result;
// Reset the transparent pixel in the color table
if (frame.transparency) {
act[frame.transIndex] = save;
}
return new BitmapResource(result, bitmapPool);
}
/**
* Reads GIF image from stream
*
* @param is containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(InputStream is, int contentLength) {
if (is != null) {
try {
int capacity = (contentLength > 0) ? (contentLength + 4096) : 16384;
ByteArrayOutputStream buffer = new ByteArrayOutputStream(capacity);
int nRead;
byte[] data = new byte[16384];
while ((nRead = is.read(data, 0, data.length)) != -1) {
buffer.write(data, 0, nRead);
}
buffer.flush();
read(buffer.toByteArray());
} catch (IOException e) {
Log.w(TAG, "Error reading data from stream", e);
}
} else {
header.status = STATUS_OPEN_ERROR;
}
try {
if (is != null) {
is.close();
}
} catch (IOException e) {
Log.w(TAG, "Error closing stream", e);
}
return header.status;
}
public void setData(String id, GifHeader header, byte[] data) {
this.id = id;
this.header = header;
this.data = data;
//Initialize the raw data buffer
rawData = ByteBuffer.wrap(data);
rawData.rewind();
rawData.order(ByteOrder.LITTLE_ENDIAN);
//Now that we know the size, init scratch arrays
mainPixels = new byte[header.width * header.height];
mainScratch = new int[header.width * header.height];
}
/**
* Reads GIF image from byte array
*
* @param data containing GIF file.
* @return read status code (0 = no errors)
*/
public int read(byte[] data) {
this.data = data;
this.header = new GifHeaderParser(data).parseHeader();
if (data != null) {
//Initialize the raw data buffer
rawData = ByteBuffer.wrap(data);
rawData.rewind();
rawData.order(ByteOrder.LITTLE_ENDIAN);
//Now that we know the size, init scratch arrays
mainPixels = new byte[header.width * header.height];
mainScratch = new int[header.width * header.height];
}
return header.status;
}
/**
* Creates new frame image from current data (and previous frames as specified by their disposition codes).
*/
private Bitmap setPixels(int frameIndex) {
GifFrame currentFrame = header.frames.get(frameIndex);
GifFrame previousFrame = null;
int previousIndex = frameIndex - 1;
if (previousIndex >= 0) {
previousFrame = header.frames.get(previousIndex);
}
// final location of blended pixels
final int[] dest = mainScratch;
// fill in starting image contents based on last image's dispose code
if (previousFrame != null && previousFrame.dispose > DISPOSAL_UNSPECIFIED) {
if (previousFrame.dispose == DISPOSAL_NONE && currentImage != null) {
// Start with the current image
currentImage.getPixels(dest, 0, header.width, 0, 0, header.width, header.height);
}
if (previousFrame.dispose == DISPOSAL_BACKGROUND) {
// Start with a canvas filled with the background color
int c = 0;
if (!currentFrame.transparency) {
c = header.bgColor;
}
for (int i = 0; i < previousFrame.ih; i++) {
int n1 = (previousFrame.iy + i) * header.width + previousFrame.ix;
int n2 = n1 + previousFrame.iw;
for (int k = n1; k < n2; k++) {
dest[k] = c;
}
}
}
} else {
int c = 0;
if (!currentFrame.transparency) {
c = header.bgColor;
}
for (int i = 0; i < dest.length; i++) {
dest[i] = c;
}
}
//Decode pixels for this frame into the global pixels[] scratch
decodeBitmapData(currentFrame, mainPixels); // decode pixel data
// copy each source line to the appropriate place in the destination
int pass = 1;
int inc = 8;
int iline = 0;
for (int i = 0; i < currentFrame.ih; i++) {
int line = i;
if (currentFrame.interlace) {
if (iline >= currentFrame.ih) {
pass++;
switch (pass) {
case 2:
iline = 4;
break;
case 3:
iline = 2;
inc = 4;
break;
case 4:
iline = 1;
inc = 2;
break;
default:
break;
}
}
line = iline;
iline += inc;
}
line += currentFrame.iy;
if (line < header.height) {
int k = line * header.width;
int dx = k + currentFrame.ix; // start of line in dest
int dlim = dx + currentFrame.iw; // end of dest line
if ((k + header.width) < dlim) {
dlim = k + header.width; // past dest edge
}
int sx = i * currentFrame.iw; // start of line in source
while (dx < dlim) {
// map color and insert in destination
int index = ((int) mainPixels[sx++]) & 0xff;
int c = act[index];
if (c != 0) {
dest[dx] = c;
}
dx++;
}
}
}
//Set pixels for current image
Bitmap result = getNextBitmap();
result.setPixels(dest, 0, header.width, 0, 0, header.width, header.height);
return result;
}
/**
* Decodes LZW image data into pixel array. Adapted from John Cristy's BitmapMagick.
*/
private void decodeBitmapData(GifFrame frame, byte[] dstPixels) {
if (frame != null) {
//Jump to the frame start position
rawData.position(frame.bufferFrameStart);
}
int nullCode = -1;
int npix = (frame == null) ? header.width * header.height : frame.iw * frame.ih;
int available, clear, code_mask, code_size, end_of_information, in_code, old_code, bits, code, count, i, datum, data_size, first, top, bi, pi;
if (dstPixels == null || dstPixels.length < npix) {
dstPixels = new byte[npix]; // allocate new pixel array
}
if (prefix == null) {
prefix = new short[MAX_STACK_SIZE];
}
if (suffix == null) {
suffix = new byte[MAX_STACK_SIZE];
}
if (pixelStack == null) {
pixelStack = new byte[MAX_STACK_SIZE + 1];
}
// Initialize GIF data stream decoder.
data_size = read();
clear = 1 << data_size;
end_of_information = clear + 1;
available = clear + 2;
old_code = nullCode;
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
for (code = 0; code < clear; code++) {
prefix[code] = 0; // XXX ArrayIndexOutOfBoundsException
suffix[code] = (byte) code;
}
// Decode GIF pixel stream.
datum = bits = count = first = top = pi = bi = 0;
for (i = 0; i < npix; ) {
if (top == 0) {
if (bits < code_size) {
// Load bytes until there are enough bits for a code.
if (count == 0) {
// Read a new data block.
count = readBlock();
if (count <= 0) {
break;
}
bi = 0;
}
datum += (((int) block[bi]) & 0xff) << bits;
bits += 8;
bi++;
count--;
continue;
}
// Get the next code.
code = datum & code_mask;
datum >>= code_size;
bits -= code_size;
// Interpret the code
if ((code > available) || (code == end_of_information)) {
break;
}
if (code == clear) {
// Reset decoder.
code_size = data_size + 1;
code_mask = (1 << code_size) - 1;
available = clear + 2;
old_code = nullCode;
continue;
}
if (old_code == nullCode) {
pixelStack[top++] = suffix[code];
old_code = code;
first = code;
continue;
}
in_code = code;
if (code == available) {
pixelStack[top++] = (byte) first;
code = old_code;
}
while (code > clear) {
pixelStack[top++] = suffix[code];
code = prefix[code];
}
first = ((int) suffix[code]) & 0xff;
// Add a new string to the string table,
if (available >= MAX_STACK_SIZE) {
break;
}
pixelStack[top++] = (byte) first;
prefix[available] = (short) old_code;
suffix[available] = (byte) first;
available++;
if (((available & code_mask) == 0) && (available < MAX_STACK_SIZE)) {
code_size++;
code_mask += available;
}
old_code = in_code;
}
// Pop a pixel off the pixel stack.
top--;
dstPixels[pi++] = pixelStack[top];
i++;
}
for (i = pi; i < npix; i++) {
dstPixels[i] = 0; // clear missing pixels
}
}
/**
* Reads a single byte from the input stream.
*/
private int read() {
int curByte = 0;
try {
curByte = (rawData.get() & 0xFF);
} catch (Exception e) {
header.status = STATUS_FORMAT_ERROR;
}
return curByte;
}
/**
* Reads next variable length block from input.
*
* @return number of bytes stored in "buffer"
*/
private int readBlock() {
int blockSize = read();
int n = 0;
if (blockSize > 0) {
try {
int count;
while (n < blockSize) {
count = blockSize - n;
rawData.get(block, n, count);
n += count;
}
} catch (Exception e) {
Log.w(TAG, "Error Reading Block", e);
header.status = STATUS_FORMAT_ERROR;
}
}
return n;
}
private Bitmap getNextBitmap() {
Bitmap.Config targetConfig = header.isTransparent ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
Bitmap result = bitmapPool.get(header.width, header.height, targetConfig);
if (result == null) {
result = Bitmap.createBitmap(header.width, header.height, targetConfig);
}
return result;
}
}