/*!
This function decodes some data into image changes.
Returns the number of bytes consumed.
*/
int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
int *nextFrameDelay, int *loopCount, QSize *nextSize)
{
// We are required to state that
// "The Graphics Interchange Format(c) is the Copyright property of
// CompuServe Incorporated. GIF(sm) is a Service Mark property of
// CompuServe Incorporated."
#define LM(l, m) (((m)<<8)|l)
digress = false;
int initial = length;
while (!digress && length) {
length--;
unsigned char ch=*buffer++;
switch (state) {
case Header:
hold[count++]=ch;
if (count==6) {
// Header
gif89=(hold[3]!='8' || hold[4]!='7');
state=LogicalScreenDescriptor;
count=0;
}
break;
case LogicalScreenDescriptor:
hold[count++]=ch;
if (count==7) {
// Logical Screen Descriptor
swidth=LM(hold[0], hold[1]);
sheight=LM(hold[2], hold[3]);
gcmap=!!(hold[4]&0x80);
//UNUSED: bpchan=(((hold[4]&0x70)>>3)+1);
//UNUSED: gcmsortflag=!!(hold[4]&0x08);
gncols=2<<(hold[4]&0x7);
bgcol=(gcmap) ? hold[5] : -1;
//aspect=hold[6] ? double(hold[6]+15)/64.0 : 1.0;
trans_index = -1;
count=0;
ncols=gncols;
if (gcmap) {
ccount=0;
state=GlobalColorMap;
globalcmap = new QRgb[gncols+1]; // +1 for trans_index
globalcmap[gncols] = Q_TRANSPARENT;
} else {
state=Introducer;
}
}
break;
case GlobalColorMap: case LocalColorMap:
hold[count++]=ch;
if (count==3) {
QRgb rgb = qRgb(hold[0], hold[1], hold[2]);
if (state == LocalColorMap) {
if (ccount < lncols)
localcmap[ccount] = rgb;
} else {
globalcmap[ccount] = rgb;
}
if (++ccount >= ncols) {
if (state == LocalColorMap)
state=TableImageLZWSize;
else
state=Introducer;
}
count=0;
}
break;
case Introducer:
hold[count++]=ch;
switch (ch) {
case ',':
state=ImageDescriptor;
break;
case '!':
state=ExtensionLabel;
break;
case ';':
// ### Changed: QRect(0, 0, swidth, sheight)
state=Done;
break;
default:
digress=true;
// Unexpected Introducer - ignore block
state=Error;
}
break;
case ImageDescriptor:
hold[count++]=ch;
if (count==10) {
int newleft=LM(hold[1], hold[2]);
int newtop=LM(hold[3], hold[4]);
int newwidth=LM(hold[5], hold[6]);
int newheight=LM(hold[7], hold[8]);
// disbelieve ridiculous logical screen sizes,
// unless the image frames are also large.
if (swidth/10 > qMax(newwidth,200))
swidth = -1;
if (sheight/10 > qMax(newheight,200))
sheight = -1;
if (swidth <= 0)
swidth = newleft + newwidth;
if (sheight <= 0)
sheight = newtop + newheight;
QImage::Format format = trans_index >= 0 ? QImage::Format_ARGB32 : QImage::Format_RGB32;
if (image->isNull() || (image->size() != QSize(swidth, sheight)) || image->format() != format) {
(*image) = QImage(swidth, sheight, format);
memset(image->bits(), 0, image->numBytes());
// ### size of the upcoming frame, should rather
// be known before decoding it.
*nextSize = QSize(swidth, sheight);
}
disposePrevious(image);
disposed = false;
left = newleft;
top = newtop;
width = newwidth;
height = newheight;
right=qMax(0, qMin(left+width, swidth)-1);
bottom=qMax(0, qMin(top+height, sheight)-1);
lcmap=!!(hold[9]&0x80);
interlace=!!(hold[9]&0x40);
//bool lcmsortflag=!!(hold[9]&0x20);
lncols=lcmap ? (2<<(hold[9]&0x7)) : 0;
if (lncols) {
if (localcmap)
delete [] localcmap;
localcmap = new QRgb[lncols+1];
localcmap[lncols] = Q_TRANSPARENT;
ncols = lncols;
} else {
ncols = gncols;
}
frame++;
if (frame == 0) {
if (left || top || width<swidth || height<sheight) {
// Not full-size image - erase with bg or transparent
if (trans_index >= 0) {
fillRect(image, 0, 0, swidth, sheight, color(trans_index));
// ### Changed: QRect(0, 0, swidth, sheight)
} else if (bgcol>=0) {
fillRect(image, 0, 0, swidth, sheight, color(bgcol));
// ### Changed: QRect(0, 0, swidth, sheight)
}
}
}
if (disposal == RestoreImage) {
int l = qMin(swidth-1,left);
int r = qMin(swidth-1,right);
int t = qMin(sheight-1,top);
int b = qMin(sheight-1,bottom);
int w = r-l+1;
int h = b-t+1;
if (backingstore.width() < w
|| backingstore.height() < h) {
// We just use the backing store as a byte array
backingstore = QImage(qMax(backingstore.width(), w),
qMax(backingstore.height(), h),
QImage::Format_RGB32);
memset(image->bits(), 0, image->numBytes());
}
for (int ln=0; ln<h; ln++) {
memcpy(backingstore.scanLine(ln),
image->scanLine(t+ln)+l, w*sizeof(QRgb));
}
}
count=0;
if (lcmap) {
ccount=0;
state=LocalColorMap;
} else {
state=TableImageLZWSize;
}
x = left;
y = top;
accum = 0;
bitcount = 0;
sp = stack;
firstcode = oldcode = 0;
needfirst = true;
out_of_bounds = left>=swidth || y>=sheight;
}
break;
case TableImageLZWSize: {
lzwsize=ch;
if (lzwsize > max_lzw_bits) {
state=Error;
} else {
code_size=lzwsize+1;
clear_code=1<<lzwsize;
end_code=clear_code+1;
max_code_size=2*clear_code;
max_code=clear_code+2;
int i;
for (i=0; i<clear_code; i++) {
table[0][i]=0;
table[1][i]=i;
}
state=ImageDataBlockSize;
}
count=0;
break;
} case ImageDataBlockSize:
expectcount=ch;
if (expectcount) {
state=ImageDataBlock;
} else {
state=Introducer;
digress = true;
newFrame = true;
}
break;
case ImageDataBlock:
count++;
accum|=(ch<<bitcount);
bitcount+=8;
while (bitcount>=code_size && state==ImageDataBlock) {
int code=accum&((1<<code_size)-1);
bitcount-=code_size;
accum>>=code_size;
if (code==clear_code) {
if (!needfirst) {
code_size=lzwsize+1;
max_code_size=2*clear_code;
max_code=clear_code+2;
}
needfirst=true;
} else if (code==end_code) {
bitcount = -32768;
// Left the block end arrive
} else {
if (needfirst) {
firstcode=oldcode=code;
if (!out_of_bounds && image->height() > y && firstcode!=trans_index)
((QRgb*)image->scanLine(y))[x] = color(firstcode);
x++;
if (x>=swidth) out_of_bounds = true;
needfirst=false;
if (x>=left+width) {
x=left;
out_of_bounds = left>=swidth || y>=sheight;
nextY(image);
}
} else {
incode=code;
if (code>=max_code) {
*sp++=firstcode;
code=oldcode;
}
while (code>=clear_code+2) {
*sp++=table[1][code];
if (code==table[0][code]) {
state=Error;
break;
}
if (sp-stack>=(1<<(max_lzw_bits))*2) {
state=Error;
break;
}
code=table[0][code];
}
*sp++=firstcode=table[1][code];
code=max_code;
if (code<(1<<max_lzw_bits)) {
table[0][code]=oldcode;
table[1][code]=firstcode;
max_code++;
if ((max_code>=max_code_size)
&& (max_code_size<(1<<max_lzw_bits)))
{
max_code_size*=2;
code_size++;
}
}
oldcode=incode;
const int h = image->height();
const QRgb *map = lcmap ? localcmap : globalcmap;
QRgb *line = 0;
if (!out_of_bounds && h > y)
line = (QRgb*)image->scanLine(y);
while (sp>stack) {
const uchar index = *(--sp);
if (!out_of_bounds && h > y && index!=trans_index) {
if (index > ncols)
line[x] = Q_TRANSPARENT;
else
line[x] = map ? map[index] : 0;
}
x++;
if (x>=swidth) out_of_bounds = true;
if (x>=left+width) {
x=left;
out_of_bounds = left>=swidth || y>=sheight;
nextY(image);
if (!out_of_bounds && h > y)
line = (QRgb*)image->scanLine(y);
}
}
}
}
}
partialNewFrame = true;
if (count==expectcount) {
count=0;
state=ImageDataBlockSize;
}
break;
case ExtensionLabel:
switch (ch) {
case 0xf9:
state=GraphicControlExtension;
break;
case 0xff:
state=ApplicationExtension;
break;
#if 0
case 0xfe:
state=CommentExtension;
break;
case 0x01:
break;
#endif
default:
state=SkipBlockSize;
}
count=0;
break;
case ApplicationExtension:
if (count<11) hold[count]=ch;
count++;
if (count==hold[0]+1) {
if (qstrncmp((char*)(hold+1), "NETSCAPE", 8)==0) {
// Looping extension
state=NetscapeExtensionBlockSize;
} else {
state=SkipBlockSize;
}
count=0;
}
break;
case NetscapeExtensionBlockSize:
expectcount=ch;
count=0;
if (expectcount) state=NetscapeExtensionBlock;
else state=Introducer;
break;
case NetscapeExtensionBlock:
if (count<3) hold[count]=ch;
count++;
if (count==expectcount) {
*loopCount = hold[1]+hold[2]*256;
state=SkipBlockSize; // Ignore further blocks
}
break;
case GraphicControlExtension:
if (count<5) hold[count]=ch;
count++;
if (count==hold[0]+1) {
disposePrevious(image);
disposal=Disposal((hold[1]>>2)&0x7);
//UNUSED: waitforuser=!!((hold[1]>>1)&0x1);
int delay=count>3 ? LM(hold[2], hold[3]) : 1;
// IE and mozilla use a minimum delay of 10. With the minimum delay of 10
// we are compatible to them and avoid huge loads on the app and xserver.
*nextFrameDelay = (delay < 2 ? 10 : delay) * 10;
bool havetrans=hold[1]&0x1;
trans_index = havetrans ? hold[4] : -1;
count=0;
state=SkipBlockSize;
}
break;
case SkipBlockSize:
expectcount=ch;
count=0;
if (expectcount) state=SkipBlock;
else state=Introducer;
break;
case SkipBlock:
count++;
if (count==expectcount) state=SkipBlockSize;
break;
case Done:
digress=true;
/* Netscape ignores the junk, so we do too.
length++; // Unget
state=Error; // More calls to this is an error
*/
break;
case Error:
return -1; // Called again after done.
}
}
/*!
This function decodes some data into image changes.
Returns the number of bytes consumed.
*/
int QGIFFormat::decode(QImage& img, QImageConsumer* consumer,
const uchar* buffer, int length)
{
// We are required to state that
// "The Graphics Interchange Format(c) is the Copyright property of
// CompuServe Incorporated. GIF(sm) is a Service Mark property of
// CompuServe Incorporated."
#define LM(l, m) (((m)<<8)|l)
digress = FALSE;
int initial = length;
QRgb** line = (QRgb **)img.jumpTable();
while (!digress && length) {
length--;
unsigned char ch=*buffer++;
switch (state) {
case Header:
hold[count++]=ch;
if (count==6) {
// Header
gif89=(hold[3]!='8' || hold[4]!='7');
state=LogicalScreenDescriptor;
count=0;
}
break;
case LogicalScreenDescriptor:
hold[count++]=ch;
if (count==7) {
// Logical Screen Descriptor
swidth=LM(hold[0], hold[1]);
sheight=LM(hold[2], hold[3]);
gcmap=!!(hold[4]&0x80);
//UNUSED: bpchan=(((hold[4]&0x70)>>3)+1);
//UNUSED: gcmsortflag=!!(hold[4]&0x08);
gncols=2<<(hold[4]&0x7);
bgcol=(gcmap) ? hold[5] : -1;
//aspect=hold[6] ? double(hold[6]+15)/64.0 : 1.0;
trans_index = -1;
count=0;
ncols=gncols;
if (gcmap) {
ccount=0;
state=GlobalColorMap;
globalcmap = new QRgb[gncols+1]; // +1 for trans_index
globalcmap[gncols] = Q_TRANSPARENT;
} else {
state=Introducer;
}
}
break;
case GlobalColorMap: case LocalColorMap:
hold[count++]=ch;
if (count==3) {
QRgb rgb = qRgb(hold[0], hold[1], hold[2]);
if ( state == LocalColorMap ) {
if ( ccount < lncols )
localcmap[ccount] = rgb;
} else {
globalcmap[ccount] = rgb;
}
if (++ccount >= ncols) {
if ( state == LocalColorMap )
state=TableImageLZWSize;
else
state=Introducer;
}
count=0;
}
break;
case Introducer:
hold[count++]=ch;
switch (ch) {
case ',':
state=ImageDescriptor;
break;
case '!':
state=ExtensionLabel;
break;
case ';':
if (consumer) {
if ( out_of_bounds ) // flush anything that survived
consumer->changed(QRect(0,0,swidth,sheight));
consumer->end();
}
state=Done;
break;
default:
digress=TRUE;
// Unexpected Introducer - ignore block
state=Error;
}
break;
case ImageDescriptor:
hold[count++]=ch;
if (count==10) {
int newleft=LM(hold[1], hold[2]);
int newtop=LM(hold[3], hold[4]);
int width=LM(hold[5], hold[6]);
int height=LM(hold[7], hold[8]);
// disbelieve ridiculous logical screen sizes,
// unless the image frames are also large.
if ( swidth/10 > QMAX(width,200) )
swidth = -1;
if ( sheight/10 > QMAX(height,200) )
sheight = -1;
if ( swidth <= 0 )
swidth = newleft + width;
if ( sheight <= 0 )
sheight = newtop + height;
if (img.isNull()) {
img.create(swidth, sheight, 32);
memset( img.bits(), 0, img.numBytes() );
if (consumer) consumer->setSize(swidth, sheight);
}
img.setAlphaBuffer(trans_index >= 0);
line = (QRgb **)img.jumpTable();
disposePrevious( img, consumer );
disposed = FALSE;
left = newleft;
top = newtop;
// Sanity check frame size - must fit on "screen".
if (left >= swidth) left=QMAX(0, swidth-1);
if (top >= sheight) top=QMAX(0, sheight-1);
if (left+width >= swidth) {
if ( width <= swidth )
left=swidth-width;
else
width=swidth-left;
}
if (top+height >= sheight) {
if ( height <= sheight )
top=sheight-height;
else
height=sheight-top;
}
right=QMAX( 0, left+width-1);
bottom=QMAX(0, top+height-1);
lcmap=!!(hold[9]&0x80);
interlace=!!(hold[9]&0x40);
//bool lcmsortflag=!!(hold[9]&0x20);
lncols=lcmap ? (2<<(hold[9]&0x7)) : 0;
if (lncols) {
if ( localcmap )
delete [] localcmap;
localcmap = new QRgb[lncols+1];
localcmap[lncols] = Q_TRANSPARENT;
ncols = lncols;
} else {
ncols = gncols;
}
frame++;
if ( frame == 0 ) {
if ( left || top || width!=swidth || height!=sheight ) {
// Not full-size image - erase with bg or transparent
if ( trans_index >= 0 ) {
fillRect(img, 0, 0, swidth, sheight, color(trans_index));
if (consumer) consumer->changed(QRect(0,0,swidth,sheight));
} else if ( bgcol>=0 ) {
fillRect(img, 0, 0, swidth, sheight, color(bgcol));
if (consumer) consumer->changed(QRect(0,0,swidth,sheight));
}
}
}
if ( disposal == RestoreImage ) {
int l = QMIN(swidth-1,left);
int r = QMIN(swidth-1,right);
int t = QMIN(sheight-1,top);
int b = QMIN(sheight-1,bottom);
int w = r-l+1;
int h = b-t+1;
if (backingstore.width() < w
|| backingstore.height() < h) {
// We just use the backing store as a byte array
backingstore.create( QMAX(backingstore.width(), w),
QMAX(backingstore.height(), h),
32);
memset( img.bits(), 0, img.numBytes() );
}
for (int ln=0; ln<h; ln++) {
memcpy(backingstore.scanLine(ln),
line[t+ln]+l, w*sizeof(QRgb));
}
}
count=0;
if (lcmap) {
ccount=0;
state=LocalColorMap;
} else {
state=TableImageLZWSize;
}
x = left;
y = top;
accum = 0;
bitcount = 0;
sp = stack;
needfirst = FALSE;
out_of_bounds = FALSE;
}
break;
case TableImageLZWSize: {
lzwsize=ch;
if ( lzwsize > max_lzw_bits ) {
state=Error;
} else {
code_size=lzwsize+1;
clear_code=1<<lzwsize;
end_code=clear_code+1;
max_code_size=2*clear_code;
max_code=clear_code+2;
int i;
for (i=0; i<clear_code && i<(1<<max_lzw_bits); i++) {
table[0][i]=0;
table[1][i]=i;
}
for (i=clear_code; i<(1<<max_lzw_bits); i++) {
table[0][i]=table[1][i]=0;
}
state=ImageDataBlockSize;
}
count=0;
break;
} case ImageDataBlockSize:
expectcount=ch;
if (expectcount) {
state=ImageDataBlock;
} else {
if (consumer) {
consumer->frameDone();
digress = TRUE;
}
state=Introducer;
}
break;
case ImageDataBlock:
count++;
accum|=(ch<<bitcount);
bitcount+=8;
while (bitcount>=code_size && state==ImageDataBlock) {
int code=accum&((1<<code_size)-1);
bitcount-=code_size;
accum>>=code_size;
if (code==clear_code) {
if (!needfirst) {
int i;
code_size=lzwsize+1;
max_code_size=2*clear_code;
max_code=clear_code+2;
for (i=0; i<clear_code; i++) {
table[0][i]=0;
table[1][i]=i;
}
for (i=clear_code; i<(1<<max_lzw_bits); i++) {
table[0][i]=table[1][i]=0;
}
}
needfirst=TRUE;
} else if (code==end_code) {
bitcount = -32768;
// Left the block end arrive
} else {
if (needfirst) {
firstcode=oldcode=code;
if (!out_of_bounds && line && firstcode!=trans_index)
line[y][x] = color(firstcode);
x++;
if (x>=swidth) out_of_bounds = TRUE;
needfirst=FALSE;
if (x>right) {
x=left;
if (out_of_bounds)
out_of_bounds = left>=swidth || y>=sheight;
nextY(img,consumer);
}
} else {
incode=code;
if (code>=max_code) {
*sp++=firstcode;
code=oldcode;
}
while (code>=clear_code) {
*sp++=table[1][code];
if (code==table[0][code]) {
state=Error;
break;
}
if (sp-stack>=(1<<(max_lzw_bits))*2) {
state=Error;
break;
}
code=table[0][code];
}
*sp++=firstcode=table[1][code];
code=max_code;
if (code<(1<<max_lzw_bits)) {
table[0][code]=oldcode;
table[1][code]=firstcode;
max_code++;
if ((max_code>=max_code_size)
&& (max_code_size<(1<<max_lzw_bits)))
{
max_code_size*=2;
code_size++;
}
}
oldcode=incode;
while (sp>stack) {
--sp;
if (!out_of_bounds && *sp!=trans_index)
line[y][x] = color(*sp);
x++;
if (x>=swidth) out_of_bounds = TRUE;
if (x>right) {
x=left;
if (out_of_bounds)
out_of_bounds = left>=swidth || y>=sheight;
nextY(img,consumer);
}
}
}
}
}
if (count==expectcount) {
count=0;
state=ImageDataBlockSize;
}
break;
case ExtensionLabel:
switch (ch) {
case 0xf9:
state=GraphicControlExtension;
break;
case 0xff:
state=ApplicationExtension;
break;
#if 0
case 0xfe:
state=CommentExtension;
break;
case 0x01:
break;
#endif
default:
state=SkipBlockSize;
}
count=0;
break;
case ApplicationExtension:
if (count<11) hold[count]=ch;
count++;
if (count==hold[0]+1) {
if (qstrncmp((char*)(hold+1), "NETSCAPE", 8)==0) {
// Looping extension
state=NetscapeExtensionBlockSize;
} else {
state=SkipBlockSize;
}
count=0;
}
break;
case NetscapeExtensionBlockSize:
expectcount=ch;
count=0;
if (expectcount) state=NetscapeExtensionBlock;
else state=Introducer;
break;
case NetscapeExtensionBlock:
if (count<3) hold[count]=ch;
count++;
if (count==expectcount) {
int loop = hold[0]+hold[1]*256;
if (consumer) consumer->setLooping(loop);
state=SkipBlockSize; // Ignore further blocks
}
break;
case GraphicControlExtension:
if (count<5) hold[count]=ch;
count++;
if (count==hold[0]+1) {
disposePrevious( img, consumer );
disposal=Disposal((hold[1]>>2)&0x7);
//UNUSED: waitforuser=!!((hold[1]>>1)&0x1);
int delay=count>3 ? LM(hold[2], hold[3]) : 1;
// IE and mozilla use a minimum delay of 10. With the minumum delay of 10
// we are compatible to them and avoid huge loads on the app and xserver.
if ( delay < 10 )
delay = 10;
bool havetrans=hold[1]&0x1;
trans_index = havetrans ? hold[4] : -1;
if (consumer) consumer->setFramePeriod(delay*10);
count=0;
state=SkipBlockSize;
}
break;
case SkipBlockSize:
expectcount=ch;
count=0;
if (expectcount) state=SkipBlock;
else state=Introducer;
break;
case SkipBlock:
count++;
if (count==expectcount) state=SkipBlockSize;
break;
case Done:
digress=TRUE;
/* Netscape ignores the junk, so we do too.
length++; // Unget
state=Error; // More calls to this is an error
*/
break;
case Error:
return -1; // Called again after done.
}
}
