public int read(byte[] b, int st, int len) throws IOException {
if (owner.chunkLength <= 0) if (!owner.getData()) return -1;
if (owner.chunkLength < len) len = owner.chunkLength;
System.arraycopy(owner.inbuf, owner.chunkStart, b, st, len);
owner.chunkLength -= len;
owner.chunkStart += len;
return len;
}
private boolean need(int n) throws IOException {
if (limit - pos >= n) return true;
fill();
if (limit - pos >= n) return true;
if (seenEOF) return false;
byte nin[] = new byte[n + 100];
System.arraycopy(inbuf, pos, nin, 0, limit - pos);
limit = limit - pos;
pos = 0;
inbuf = nin;
fill();
return limit - pos >= n;
}
private void fill() throws IOException {
if (!seenEOF) {
if (pos > 0 && pos < limit) {
System.arraycopy(inbuf, pos, inbuf, 0, limit - pos);
limit = limit - pos;
pos = 0;
} else if (pos >= limit) {
pos = 0;
limit = 0;
}
int bsize = inbuf.length;
while (limit < bsize) {
int n = underlyingInputStream.read(inbuf, limit, bsize - limit);
if (n <= 0) {
seenEOF = true;
break;
}
limit += n;
}
}
}
protected boolean handleChunk(int key, byte[] buf, int st, int len) throws IOException {
switch (key) {
case bKGDChunk:
Color c = null;
switch (colorType) {
case COLOR:
case COLOR | ALPHA:
pngassert(len == 6);
c = new Color(buf[st] & 0xff, buf[st + 2] & 0xff, buf[st + 4] & 0xff);
break;
case COLOR | PALETTE:
case COLOR | PALETTE | ALPHA:
pngassert(len == 1);
int ix = buf[st] & 0xFF;
pngassert(red_map != null && ix < red_map.length);
c = new Color(red_map[ix] & 0xff, green_map[ix] & 0xff, blue_map[ix] & 0xff);
break;
case GRAY:
case GRAY | ALPHA:
pngassert(len == 2);
int t = buf[st] & 0xFF;
c = new Color(t, t, t);
break;
}
if (c != null) property("background", c);
break;
case cHRMChunk:
property(
"chromaticities",
new Chromaticities(
getInt(st),
getInt(st + 4),
getInt(st + 8),
getInt(st + 12),
getInt(st + 16),
getInt(st + 20),
getInt(st + 24),
getInt(st + 28)));
break;
case gAMAChunk:
if (len != 4) throw new PNGException("bogus gAMA");
gamma = getInt(st);
if (gamma != 100000) property("gamma", gamma / 100000.0f);
break;
case hISTChunk:
break;
case IDATChunk:
return false;
case IENDChunk:
break;
case IHDRChunk:
if (len != 13 || (width = getInt(st)) == 0 || (height = getInt(st + 4)) == 0)
throw new PNGException("bogus IHDR");
bitDepth = getByte(st + 8);
colorType = getByte(st + 9);
compressionMethod = getByte(st + 10);
filterMethod = getByte(st + 11);
interlaceMethod = getByte(st + 12);
/* this is not needed
if(target!=null) target.setDimensions(width,height);
*/
break;
case PLTEChunk:
{
int tsize = len / 3;
red_map = new byte[tsize];
green_map = new byte[tsize];
blue_map = new byte[tsize];
for (int i = 0, j = st; i < tsize; i++, j += 3) {
red_map[i] = buf[j];
green_map[i] = buf[j + 1];
blue_map[i] = buf[j + 2];
}
}
break;
case pHYsChunk:
break;
case sBITChunk:
break;
case tEXtChunk:
int klen = 0;
while (klen < len && buf[st + klen] != 0) klen++;
if (klen < len) {
String tkey = new String(buf, st, klen);
String tvalue = new String(buf, st + klen + 1, len - klen - 1);
property(tkey, tvalue);
}
break;
case tIMEChunk:
property(
"modtime",
new GregorianCalendar(
getShort(st + 0),
getByte(st + 2) - 1,
getByte(st + 3),
getByte(st + 4),
getByte(st + 5),
getByte(st + 6))
.getTime());
break;
case tRNSChunk:
switch (colorType) {
case PALETTE | COLOR:
case PALETTE | COLOR | ALPHA:
int alen = len;
if (red_map != null) alen = red_map.length;
alpha_map = new byte[alen];
System.arraycopy(buf, st, alpha_map, 0, len < alen ? len : alen);
while (--alen >= len) alpha_map[alen] = (byte) 0xFF;
break;
case COLOR: // doesn't deal with 16 bit colors properly
case COLOR | ALPHA: // doesn't deal with 16 bit colors properly
pngassert(len == 6);
if (bitDepth == 16) {
transparentPixel_16 = new byte[6];
for (int i = 0; i < 6; i++) {
transparentPixel_16[i] = (byte) getByte(st + i);
}
} else {
transparentPixel =
((getShort(st + 0) & 0xFF) << 16)
| ((getShort(st + 2) & 0xFF) << 8)
| ((getShort(st + 4) & 0xFF));
}
break;
case GRAY: // doesn't deal with 16 bit colors properly
case GRAY | ALPHA: // doesn't deal with 16 bit colors properly
pngassert(len == 2);
/* REMIND: Discarding the LSB for 16 bit depth here
* means that the all pixels which match the MSB
* will be treated as transparent.
*/
int t = getShort(st);
t = 0xFF & ((bitDepth == 16) ? (t >> 8) : t);
transparentPixel = (t << 16) | (t << 8) | t;
break;
}
break;
case zTXtChunk:
break;
}
return true;
}