-/*
- * This file was adapted from D J Hagberg's GifDecoder.java
- *
- * This software is copyrighted by D. J. Hagberg, Jr., and other parties.
- * The following terms apply to all files associated with the software
- * unless explicitly disclaimed in individual files.
- *
- * The authors hereby grant permission to use, copy, modify, distribute,
- * and license this software and its documentation for any purpose, provided
- * that existing copyright notices are retained in all copies and that this
- * notice is included verbatim in any distributions. No written agreement,
- * license, or royalty fee is required for any of the authorized uses.
- * Modifications to this software may be copyrighted by their authors
- * and need not follow the licensing terms described here, provided that
- * the new terms are clearly indicated on the first page of each file where
- * they apply.
- *
- * IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
- * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
- * ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
- * DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- * THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. THIS SOFTWARE
- * IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
- * NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
- * MODIFICATIONS.
- *
- * GOVERNMENT USE: If you are acquiring this software on behalf of the
- * U.S. government, the Government shall have only "Restricted Rights"
- * in the software and related documentation as defined in the Federal
- * Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you
- * are acquiring the software on behalf of the Department of Defense, the
- * software shall be classified as "Commercial Computer Software" and the
- * Government shall have only "Restricted Rights" as defined in Clause
- * 252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the
- * authors grant the U.S. Government and others acting in its behalf
- * permission to use and distribute the software in accordance with the
- * terms specified in this license.
- *
- */
-package org.xwt.translators;
-
-import org.ibex.*;
-import org.ibex.util.*;
-import java.io.BufferedInputStream;
-import java.io.InputStream;
-import java.io.IOException;
-
-/** Converts an InputStream carrying a GIF image into an ARGB int[] */
-public class GIF {
-
- // Public Methods /////////////////////////////////////////////////////////
-
- private GIF() { }
-
- private static Queue instances = new Queue(10);
-
- public static void load(InputStream is, Picture p) {
- GIF g = (GIF)instances.remove(false);
- if (g == null) g = new GIF();
- try {
- g._load(is, p);
- } catch (Exception e) {
- if (Log.on) Log.info(GIF.class, e);
- return;
- }
- // FIXME: must reset fields
- // if (instances.size() < 10) instances.append(g);
- }
-
- private void _load(InputStream is, Picture p) throws IOException {
- this.p = p;
- if (is instanceof BufferedInputStream) _in = (BufferedInputStream)is;
- else _in = new BufferedInputStream(is);
- decodeAsBufferedImage(0);
- p.isLoaded = true;
- p = null;
- _in = null;
- }
-
-
- /** Decode a particular frame from the GIF file. Frames must be decoded in order, starting with 0. */
- private void decodeAsBufferedImage(int page) throws IOException, IOException {
-
- // If the user requested a page already decoded, we cannot go back.
- if (page <= index ) return;
-
- // If we just started reading this stream, initialize the global info.
- if (index < 0 ) {
- if (!readIntoBuf(6) || _buf[0] != 'G' || _buf[1] != 'I' || _buf[2] != 'F' ||
- _buf[3] != '8' || !(_buf[4] == '7' || _buf[4] == '9') || _buf[5] != 'a')
- throw new IOException("Not a GIF8Xa file.");
- if (!readGlobalImageDescriptor()) throw new IOException("Unable to read GIF header.");
- }
-
- // Loop through the blocks in the image.
- int block_identifier;
- while (true) {
- if(!readIntoBuf(1)) throw new IOException("Unexpected EOF(1)");
- block_identifier = _buf[0];
- if (block_identifier == ';') throw new IOException("No image data");
- if (block_identifier == '!') {
- if (!readExtensionBlock()) throw new IOException("Unexpected EOF(2)");
- continue;
- }
-
- // not a valid start character -- ignore it.
- if (block_identifier != ',') continue;
-
- if (!readLocalImageDescriptor()) throw new IOException("Unexpected EOF(3)");
- p.data = new int[p.width * p.height];
- readImage();
-
- // If we did not decode the requested index, need to go on
- // to the next one (future implementations should consider
- // caching already-decoded images here to allow for random
- // access to animated GIF pages).
- index++;
- if (index < page) continue;
-
- // If we did decode the requested index, we can return.
- break;
- }
-
- // Return the image thus-far decoded
- return;
- }
-
- /** Actually read the image data */
- private void readImage()
- throws IOException, IOException {
- int len = p.width;
- int rows = p.height;
- int initialCodeSize;
- int v;
- int xpos = 0, ypos = 0, pass = 0, i;
- int prefix[] = new int[(1 << MAX_LWZ_BITS)];
- int append[] = new int[(1 << MAX_LWZ_BITS)];
- int stack[] = new int[(1 << MAX_LWZ_BITS)*2];
- int top_idx;
- int codeSize, clearCode, inCode, endCode, oldCode, maxCode, code, firstCode;
-
- // Initialize the decoder
- if (!readIntoBuf(1)) throw new IOException("Unexpected EOF decoding image");
- initialCodeSize = _buf[0];
-
- // Look at the right color map, setting up transparency if called for.
- int[] cmap = global_color_map;
- if (hascmap) cmap = color_map;
- if (trans_idx >= 0) cmap[trans_idx] = 0x00000000;
-
- /* Initialize the decoder */
- /* Set values for "special" numbers:
- * clear code reset the decoder
- * end code stop decoding
- * code size size of the next code to retrieve
- * max code next available table position
- */
- clearCode = 1 << initialCodeSize;
- endCode = clearCode + 1;
- codeSize = initialCodeSize + 1;
- maxCode = clearCode + 2;
- oldCode = -1;
- firstCode = -1;
-
- for (i = 0; i < clearCode; i++) append[i] = i;
- top_idx = 0; // top of stack.
-
- bitsInWindow = 0;
- bytes = 0;
- window = 0L;
- done = false;
- c = -1;
-
- /* Read until we finish the image */
- ypos = 0;
- for (i = 0; i < rows; i++) {
- for (xpos = 0; xpos < len;) {
-
- if (top_idx == 0) {
- /* Bummer -- our stack is empty. Now we have to work! */
- code = getCode(codeSize);
- if (code < 0) return;
-
- if (code > maxCode || code == endCode) return;
- if (code == clearCode) {
- codeSize = initialCodeSize + 1;
- maxCode = clearCode + 2;
- oldCode = -1;
- continue;
- }
-
- // Last pass reset the decoder, so the first code we
- // see must be a singleton. Seed the stack with it,
- // and set up the old/first code pointers for
- // insertion into the string table. We can't just
- // roll this into the clearCode test above, because
- // at that point we have not yet read the next code.
- if (oldCode == -1) {
- stack[top_idx++] = append[code];
- oldCode = code;
- firstCode = code;
- continue;
- }
-
- inCode = code;
-
- // maxCode is always one bigger than our
- // highest assigned code. If the code we see
- // is equal to maxCode, then we are about to
- // add a new string to the table. ???
- if (code == maxCode) {
- stack[top_idx++] = firstCode;
- code = oldCode;
- }
-
- // Populate the stack by tracing the string in the
- // string table from its tail to its head
- while (code > clearCode) {
- stack[top_idx++] = append[code];
- code = prefix[code];
- }
- firstCode = append[code];
-
- // If there's no more room in our string table, quit.
- // Otherwise, add a new string to the table
- if (maxCode >= (1 << MAX_LWZ_BITS)) return;
-
- // Push the head of the string onto the stack
- stack[top_idx++] = firstCode;
-
- // Add a new string to the string table
- prefix[maxCode] = oldCode;
- append[maxCode] = firstCode;
- maxCode++;
-
- // maxCode tells us the maximum code value we can accept.
- // If we see that we need more bits to represent it than
- // we are requesting from the unpacker, we need to increase
- // the number we ask for.
- if ((maxCode >= (1 << codeSize)) && (maxCode < (1<<MAX_LWZ_BITS))) codeSize++;
- oldCode = inCode;
- }
-
- // Pop the next color index off the stack
- v = stack[--top_idx];
- if (v < 0) return;
-
- // Finally, we can set a pixel! Joy!
- p.data[xpos + ypos * p.width] = cmap[v];
- xpos++;
- }
-
- // If interlacing, the next ypos is not just +1
- if (interlaced) {
- ypos += _interlaceStep[pass];
- while (ypos >= rows) {
- pass++;
- if (pass > 3) return;
- ypos = _interlaceStart[pass];
- }
- } else ypos++;
- }
- return;
- }
-
- /** Extract the next compression code from the file. */
- private int getCode(int code_size) throws IOException {
- int ret;
-
- while (bitsInWindow < code_size) {
- // Not enough bits in our window to cover the request
- if (done) return -1;
-
- if (bytes == 0) {
- // Not enough bytes in our buffer to add to the window
- bytes = getDataBlock();
- c = 0;
- if (bytes <= 0) {
- done = true;
- break;
- }
- }
- // Tack another byte onto the window, see if that's enough
- window += (_buf[c]) << bitsInWindow;
- ++c;
- bitsInWindow += 8;
- bytes--;
- }
-
-
- // The next code will always be the last code_size bits of the window
- ret = ((int)window) & ((1 << code_size) - 1);
-
- // Shift data in the window to put the next code at the end
- window >>= code_size;
- bitsInWindow -= code_size;
- return ret;
- }
-
- /** Read the global image descriptor and optional global color map. Sets global_* variables. */
- private boolean readGlobalImageDescriptor() throws IOException {
- int packed;
- int aspect; // we ignore this.
- int ofs;
-
- if (!readIntoBuf(7) ) return false;
- global_width = _buf[0] | (_buf[1] << 8);
- global_height = _buf[2] | (_buf[3] << 8);
- packed = _buf[4];
- global_bgcolor = _buf[5];
- aspect = _buf[6];
- global_cmapsize = 2 << (packed & 0x07);
- global_hascmap = (packed & GLOBALCOLORMAP) == GLOBALCOLORMAP;
- global_color_map = null;
-
- // Read the color map, if we have one.
- if (global_hascmap) {
- if (!readColorMap(global_cmapsize,true)) {
- return false;
- }
- }
-
- return true;
- }
-
- /** Read a local image descriptor and optional local color map. */
- private boolean readLocalImageDescriptor() throws IOException {
- int packed;
-
- if (!readIntoBuf(9) ) return false;
-
- left = _buf[0] | (_buf[1] << 8);
- top = _buf[2] | (_buf[3] << 8);
- p.width = _buf[4] | (_buf[5] << 8);
- p.height = _buf[6] | (_buf[7] << 8);
- packed = _buf[8];
- hascmap = (packed & LOCALCOLORMAP) == LOCALCOLORMAP;
- cmapsize = 2 << (packed & 0x07);
- interlaced = (packed & INTERLACE) == INTERLACE;
- color_map = null;
-
- // Read the local color table, if there is one.
- return !(hascmap && !readColorMap(cmapsize,false));
- }
-
- /** Read a color map (global or local). */
- private boolean readColorMap(int nColors, boolean isGlobal)
- throws IOException {
- int[] map = new int[nColors];
- for( int i=0; i < nColors; ++i) {
- if (!readIntoBuf(3) ) return false;
- map[i] = (_buf[0] << 16) | (_buf[1] << 8) | _buf[2] | 0xFF000000;
- }
- if (isGlobal) global_color_map = map;
- else color_map = map;
- return true;
- }
-
- /** Read the contents of a GIF89a Graphical Extension Block. */
- private boolean readExtensionBlock() throws IOException {
- if (!readIntoBuf(1) ) return false;
- int label = _buf[0];
- int count = -1;
- switch (label) {
- case 0x01: // Plain Text Extension
- case 0xff: // Application Extension
- case 0xfe: // Comment Extension
- break;
- case 0xf9: // Graphic Control Extension
- count = getDataBlock();
- if (count < 0) return true;
- // Check for transparency setting.
- if ((_buf[0] & HASTRANSPARENCY) != 0) trans_idx = _buf[3];
- else trans_idx = -1;
- }
- do { count = getDataBlock(); } while (count > 0);
- return true;
- }
-
- /** Read a block of data from the GIF file. */
- private int getDataBlock() throws IOException {
- if (!readIntoBuf(1) ) return -1;
- int count = _buf[0];
- if (count != 0) if (!readIntoBuf(count) ) return -1;
- return count;
- }
-
- /** Read the indicated number of bytes into _buf, our instance-wide buffer. */
- private boolean readIntoBuf(int count) throws IOException {
- for(int i = 0; i < count; i++) if ((_buf[i] = _in.read()) == -1) return false;
- return true;
- }
-
- // Private Data //////////////////////////////////////////////////////////
-
- private Picture p;
-
- // State management stuff
- private int index = -1;
- private BufferedInputStream _in = null;
- private int[] _buf = new int[BUFSIZE];
-
- // Transparency settings
- private int trans_idx = -1;
-
- // Global image descriptor contents
- private int global_width = 0;
- private int global_height = 0;
- private int global_bgcolor = 0;
- private int global_cmapsize = 0;
- private boolean global_hascmap = false;
- private int[] global_color_map = null;
-
- // Local image descriptor contents
- private int left = 0;
- private int top = 0;
- private int cmapsize = 0;
- private boolean hascmap = false;
- private boolean interlaced = false;
- private int[] color_map = null;
-
- // Variables used in getCode(...) to track sliding bit-window.
- private int bytes = 0;
- private boolean done;
- private int c;
- private long window;
- private int bitsInWindow = 0;
-
- // Class-wide constants.
- private static final int INTERLACE = 0x40;
- private static final int GLOBALCOLORMAP = 0x80;
- private static final int LOCALCOLORMAP = 0x80;
- private static final int HASTRANSPARENCY = 0x01;
- private static final int MAX_LWZ_BITS = 12;
- private static final int BUFSIZE = 280;
- private static final int[] _interlaceStep = { 8, 8, 4, 2 };
- private static final int[] _interlaceStart = { 0, 4, 2, 1 };
-}
-
-
-
projects / org.ibex.core.git / blobdiff