ref: a920c765f2b4130590fb5971a50690b21664957a
dir: /appl/charon/img.b/
implement Img;
include "common.m";
# headers for png support
include "filter.m";
include "crc.m";
# big tables in separate files
include "rgb.inc";
include "ycbcr.inc";
include "xxx.inc";
# local copies from CU
sys: Sys;
CU: CharonUtils;
Header, ByteSource, MaskedImage, ImageCache, ResourceState: import CU;
D: Draw;
Chans, Point, Rect, Image, Display: import D;
E: Events;
Event: import E;
G: Gui;
# channel descriptions
CRGB: con 0; # three channels, R, G, B, no map
CY: con 1; # one channel, luminance
CRGB1: con 2; # one channel, map present
CYCbCr: con 3; # three channels, Y, Cb, Cr, no map
dbg := 0;
dbgev := 0;
warn := 0;
progressive := 0;
display: ref D->Display;
inflate: Filter;
crc: Crc;
CRCstate: import crc;
init(cu: CharonUtils)
{
sys = load Sys Sys->PATH;
CU = cu;
D = load Draw Draw->PATH;
G = cu->G;
crc = load Crc Crc->PATH;
inflate = load Filter "/dis/lib/inflate.dis";
inflate->init();
init_tabs();
}
# Return true if mtype is an image type we can handle
supported(mtype: int) : int
{
case mtype {
CU->ImageJpeg or
CU->ImageGif or
CU->ImageXXBitmap or
CU->ImageXInfernoBit or
CU->ImagePng =>
return 1;
}
return 0;
}
# w,h passed in are specified width and height.
# Result will be resampled if they don't match the dimensions
# in the decoded picture (if only one of w,h is specified, the other
# dimension is scaled by the same factor).
ImageSource.new(bs: ref ByteSource, w, h: int) : ref ImageSource
{
dbg = int (CU->config).dbg['i'];
warn = (int (CU->config).dbg['w']) || dbg;
dbgev = int (CU->config).dbg['e'];
display = G->display;
mtype := CU->UnknownType;
if(bs.hdr != nil)
mtype = bs.hdr.mtype;
is := ref ImageSource(
w,h, # width, height
0,0, # origw, origh
mtype, # mtype
0, # i
0, # curframe
bs, # bs
nil, # ghdr
nil, # jhdr
"" # err
);
return is;
}
ImageSource.free(is: self ref ImageSource)
{
is.bs = nil;
is.gstate = nil;
is.jstate = nil;
}
ImageSource.getmim(is: self ref ImageSource) : (int, ref MaskedImage)
{
if(dbg)
sys->print("img: getmim\n");
if(dbgev)
CU->event("IMAGE_GETMIM", is.width*is.height);
ans : ref MaskedImage = nil;
ret := Mimnone;
prtype := 0;
{
if(is.bs.hdr == nil)
return (Mimnone, nil);
# temporary hack: wait until whole file is here first
if(is.bs.eof) {
if(is.mtype == CU->UnknownType) {
u := is.bs.req.url;
h := is.bs.hdr;
h.setmediatype(u.path, is.bs.data);
is.mtype = h.mtype;
}
case is.mtype {
CU->ImageJpeg =>
ans = getjpegmim(is);
CU->ImageGif =>
ans = getgifmim(is);
CU->ImageXXBitmap =>
ans = getxbitmapmim(is);
CU->ImageXInfernoBit =>
ans = getbitmim(is);
CU->ImagePng =>
ans = getpngmim(is);
* =>
is.err = sys->sprint("unsupported image type %s", (CU->mnames)[is.mtype]);
ret = Mimerror;
ans = nil;
}
if(ans != nil)
ret = Mimdone;
}
else {
# slow down the spin-waiting for this image
sys->sleep(100);
}
}exception ex{
"exImageerror*" =>
ret = Mimerror;
if(dbg)
sys->print("getmim got err: %s\n", is.err);
}
if(dbg)
sys->print("img: getmim returns (%d,%x)\n", ret, ans);
if(dbgev)
CU->event("IMAGE_GETMIM_END", 0);
is.bs.lim = is.i;
return (ret, ans);
}
# Raise exImagerror exception
imgerror(is: ref ImageSource, msg: string)
{
is.err = msg;
if(dbg)
sys->print("Image error: %s\n", msg);
raise "exImageerror:";
}
# Get next char or raise exception if cannot
getc(is: ref ImageSource) : int
{
if(is.i >= len is.bs.data) {
imgerror(is, "premature eof");
}
return int is.bs.data[is.i++];
}
# Unget the last character.
# When called before any other getting routines, we
# know the buffer still has that character in it.
ungetc(is: ref ImageSource)
{
if(is.i == 0)
raise "EXInternal: ungetc past beginning of buffer";
is.i--;
}
# Like ungetc, but ungets two bytes (gotten in order b1, another char).
# Now the bytes could have spanned a boundary, if we were unlucky,
# so we have to be prepared to put b1 in front of current buffer.
ungetc2(is: ref ImageSource, nil: byte)
{
if(is.i < 2) {
if(is.i != 1)
raise "EXInternal: ungetc2 past beginning of buffer";
is.i = 0;
}
else
is.i -= 2;
}
# Get 2 bytes and return the 16-bit value, little-endian order.
getlew(is: ref ImageSource) : int
{
c0 := getc(is);
c1 := getc(is);
return c0 + (c1<<8);
}
# Get 2 bytes and return the 16-bit value, big-endian order.
getbew(is: ref ImageSource) : int
{
c0 := getc(is);
c1 := getc(is);
return (c0<<8) + c1;
}
# Copy next n bytes of input into buf
# or raise exception if cannot.
read(is: ref ImageSource, buf: array of byte, n: int)
{
ok := 0;
if(is.i +n < len is.bs.data) {
buf[0:] = is.bs.data[is.i:is.i+n];
is.i += n;
}
else
imgerror(is, "premature eof");
}
# Caller needs n bytes.
# Return an (array, index into array) where at least
# the next n bytes can be found.
# There might be a "premature eof" exception.
getn(is: ref ImageSource, n: int) : (array of byte, int)
{
a := is.bs.data;
i := is.i;
if(i + n <= len a)
is.i += n;
else
imgerror(is, "premature eof");
return (a, i);
}
# display.newimage with some defaults; throw exception if fails
newimage(is: ref ImageSource, w, h: int) : ref Image
{
if(!(CU->imcache).need(w*h))
imgerror(is, "out of memory");
im := display.newimage(((0,0),(w,h)), D->CMAP8, 0, D->White);
if(im == nil)
imgerror(is, "out of memory");
return im;
}
newimage24(is: ref ImageSource, w, h: int) : ref Image
{
if(!(CU->imcache).need(w*h*3))
imgerror(is, "out of memory");
im := display.newimage(((0,0),(w,h)), D->RGB24, 0, D->White);
if(im == nil)
imgerror(is, "out of memory");
return im;
}
newimagegrey(is: ref ImageSource, w, h: int) : ref Image
{
if(!(CU->imcache).need(w*h))
imgerror(is, "out of memory");
im := display.newimage(((0,0),(w,h)), D->GREY8, 0, D->White);
if(im == nil)
imgerror(is, "out of memory");
return im;
}
newmi(im: ref Image) : ref MaskedImage
{
return ref MaskedImage(im, nil, 0, 0, -1, Point(0,0));
}
# Call this after origw and origh are set to set the width and height
# to our desired (rescaled) answer dimensions.
# If only one of the dimensions is specified, the other is scaled by
# the same factor.
setdims(is: ref ImageSource)
{
sw := is.origw;
sh := is.origh;
dw := is.width;
dh := is.height;
if(dw == 0 && dh == 0) {
dw = sw;
dh = sh;
}
else if(dw == 0 || dh == 0) {
if(dw == 0) {
dw = int ((real sw) * (real dh/real sh));
if(dw == 0)
dw = 1;
}
else {
dh = int ((real sh) * (real dw/real sw));
if(dh == 0)
dh = 1;
}
}
is.width = dw;
is.height = dh;
}
# for debugging
printarray(a: array of int, name: string)
{
sys->print("%s:", name);
for(i := 0; i < len a; i++) {
if((i%10)==0)
sys->print("\n%5d: ", i);
sys->print("%6d", a[i]);
}
sys->print("\n");
}
################# XBitmap ###################
getxbitmaphdr(is: ref ImageSource)
{
fnd: int;
(fnd, is.origw) = getxbitmapdefine(is);
if(fnd)
(fnd, is.origh) = getxbitmapdefine(is);
if(!fnd)
imgerror(is, "xbitmap starts badly");
# now, optional x_hot, y_hot
(fnd, nil) = getxbitmapdefine(is);
if(fnd)
(fnd, nil) = getxbitmapdefine(is);
# now expect 'static char x...x_bits[] = {'
get_to_char(is, '{');
}
getxbitmapmim(is: ref ImageSource) : ref MaskedImage
{
getxbitmaphdr(is);
setdims(is);
bytesperline := (is.origw+7) / 8;
pixels := array[is.origw*is.origh] of byte;
pixi := 0;
for(i := 0; i < is.origh; i++) {
for(j := 0; j < bytesperline; j++) {
v := get_hexbyte(is);
kend := 7;
if(j == bytesperline-1)
kend = (is.origw-1)%8;
for(k := 0; k <= kend; k++) {
if(v & (1<<k))
pixels[pixi] = byte D->Black;
else
pixels[pixi] = byte D->White;
pixi++;
}
}
}
if(is.width != is.origw || is.height != is.origh)
pixels = resample(pixels, is.origw, is.origh, is.width, is.height);
im := newimage(is, is.width, is.height);
im.writepixels(im.r, pixels);
return newmi(im);
}
# get a line, which should be of form
# '#define fieldname val'
# and return (found, integer rep of val)
getxbitmapdefine(is: ref ImageSource) : (int, int)
{
fnd := 0;
n := 0;
c := getc(is);
if(c == '#') {
get_to_char(is, ' ');
get_to_char(is, ' ');
c = getc(is);
while(c >= '0' && c <= '9') {
fnd = 1;
n = n*10 + c - '0';
c = getc(is);
}
}
else
ungetc(is);
get_to_char(is, '\n');
return (fnd, n);
}
# read fd until get char cterm
# (raise exception if eof hit first)
get_to_char(is: ref ImageSource, cterm: int)
{
for(;;) {
if(getc(is) == cterm)
return;
}
}
# read fd until get xDD, were DD are hex digits.
# (raise exception if not hex digits or if eof hit first)
get_hexbyte(is: ref ImageSource) : int
{
get_to_char(is, 'x');
n1 := hexdig(getc(is));
n2 := hexdig(getc(is));
if(n1 < 0 || n2 < 0)
imgerror(is, "X Bitmap expected hex digits");
return (n1<<4) + n2;
}
hexdig(c: int) : int
{
if('0' <= c && c <= '9')
c -= '0';
else if('a' <= c && c <= 'f')
c += 10 - 'a';
else if('A' <= c && c <= 'F')
c += 10 - 'A';
else
c = -1;
return c;
}
################# GIF ###################
# GIF flags
TRANSP: con 1;
INPUT: con 2;
DISPMASK: con 7<<2;
HASCMAP: con 16r80;
INTERLACED: con 16r40;
Entry: adt
{
prefix: int;
exten: int;
};
getgifhdr(is: ref ImageSource)
{
if(dbg)
sys->print("img: getgifhdr\n");
h := ref Gifstate;
(buf, i) := getn(is, 6);
vers := string buf[i:i+6];
if(vers!="GIF87a" && vers!="GIF89a")
imgerror(is, "unknown GIF version " + vers);
is.origw = getlew(is);
is.origh = getlew(is);
h.fields = getc(is);
h.bgrnd = getc(is);
h.aspect = getc(is);
setdims(is);
if(dbg)
sys->print("img: getgifhdr has vers=%s, origw=%d, origh=%d, w=%d, h=%d, fields=16r%x, bgrnd=%d, aspect=%d\n",
vers, is.origw, is.origh, is.width, is.height, h.fields, h.bgrnd, h.aspect);
h.flags = 0;
h.delay = 0;
h.trindex = byte 0;
h.tbl = array[4096] of GifEntry;
for(i = 0; i < 258; i++) {
h.tbl[i].prefix = -1;
h.tbl[i].exten = i;
}
h.globalcmap = nil;
h.cmap = nil;
if(h.fields & HASCMAP)
h.globalcmap = gifreadcmap(is, (h.fields&7)+1);
is.gstate = h;
if(warn && h.aspect != 0)
sys->print("warning: non-standard aspect ratio in GIF image ignored\n");
if(!gifgettoimage(is))
imgerror(is, "GIF file has no image");
}
gifgettoimage(is: ref ImageSource) : int
{
if(dbg)
sys->print("img: gifgettoimage\n");
h := is.gstate;
loop:
for(;;) {
# some GIFs omit Trailer
if(is.i >= len is.bs.data)
break;
case c := getc(is) {
16r2C => # Image Descriptor
return 1;
16r21 => # Extension
hsize := 0;
hasdata := 0;
case getc(is){
16r01 => # Plain Text Extension
hsize = 14;
hasdata = 1;
if(dbg)
sys->print("gifgettoimage: text extension\n");
16rF9 => # Graphic Control Extension
getc(is); # blocksize (should be 4)
h.flags = getc(is);
h.delay = getlew(is);
h.trindex = byte getc(is);
getc(is); # block terminator (should be 0)
# set minimum delay
if (h.delay < 20)
h.delay = 20;
if(dbg)
sys->print("gifgettoimage: graphic control flags=16r%x, delay=%d, trindex=%d\n",
h.flags, h.delay, int h.trindex);
16rFE => # Comment Extension
if(dbg)
sys->print("gifgettoimage: comment extension\n");
hasdata = 1;
16rFF => # Application Extension
if(dbg)
sys->print("gifgettoimage: application extension\n");
hsize = getc(is);
# standard says this must be 11, but Adobe likes to put out 10-byte ones,
# so we pay attention to the field.
hasdata = 1;
* =>
imgerror(is, "GIF unknown extension");
}
if(hsize > 0)
getn(is, hsize);
if(hasdata) {
for(;;) {
if((nbytes := getc(is)) == 0)
break;
(a, i) := getn(is, nbytes);
if(dbg)
sys->print("extension data: '%s'\n", string a[i:i+nbytes]);
}
}
16r3B => # Trailer
# read to end of data
getn(is, len is.bs.data - is.i);
break loop;
* =>
if(c == 0)
continue; # FIX for some buggy gifs
imgerror(is, "GIF unknown block type " + string c);
}
}
return 0;
}
getgifmim(is: ref ImageSource) : ref MaskedImage
{
if(is.gstate == nil)
getgifhdr(is);
# At this point, should just have read Image Descriptor marker byte
h := is.gstate;
left :=getlew(is);
top := getlew(is);
width := getlew(is);
height := getlew(is);
h.fields = getc(is);
totpix := width*height;
h.cmap = h.globalcmap;
if(dbg)
sys->print("getgifmim, left=%d, top=%d, width=%d, height=%d, fields=16r%x\n",
left, top, width, height, h.fields);
if(dbgev)
CU->event("IMAGE_GETGIFMIM", 0);
if(h.fields & HASCMAP)
h.cmap = gifreadcmap(is, (h.fields&7)+1);
if(h.cmap == nil)
imgerror(is, "GIF needs colormap");
# now decode the image
c, incode: int;
codesize := getc(is);
if(codesize > 8)
imgerror(is, "GIF bad codesize");
if(len h.cmap!=3*(1<<codesize)
&& len h.cmap != 3*(1<<(codesize-1)) # peculiar GIF bitmap files
&& (codesize!=2 || len h.cmap!=3*2)){ # peculiar GIF bitmap files II
if (warn)
sys->print("warning: GIF codesize = %d doesn't match cmap len = %d\n", codesize, len h.cmap);
#imgerror(is, "GIF codesize doesn't match color map");
}
CTM :=1<<codesize;
EOD := CTM+1;
pic := array[totpix] of byte;
pici := 0;
data : array of byte = nil;
datai := 0;
dataend := 0;
nbits := 0;
sreg := 0;
stack := array[4096] of byte;
stacki: int;
fc := 0;
tbl := h.tbl;
Decode:
for(;;) {
csize := codesize+1;
csmask := ((1<<csize) - 1);
nentry := EOD+1;
maxentry := csmask;
first := 1;
ocode := -1;
for(;; ocode = incode) {
while(nbits < csize) {
if(datai == dataend) {
nbytes := getc(is);
if (nbytes == 0)
# Block Terminator
break Decode;
(data, datai) = getn(is, nbytes);
dataend = datai+nbytes;
}
c = int data[datai++];
sreg |= c<<nbits;
nbits += 8;
}
code := sreg & csmask;
sreg >>= csize;
nbits -= csize;
if(code == EOD) {
nbytes := getc(is);
if(nbytes != 0 && warn)
sys->print("warning: unexpected data past EOD\n");
break Decode;
}
if(code == CTM)
continue Decode;
stacki = len stack-1;
incode = code;
# special case for KwKwK
if(code == nentry) {
stack[stacki--] = byte fc;
code = ocode;
}
if(code > nentry)
imgerror(is, "GIF bad code");
for(c=code; c>=0; c=tbl[c].prefix)
stack[stacki--] = byte tbl[c].exten;
nb := len stack-(stacki+1);
if(pici+nb > len pic) {
# this common error is harmless
# we have to keep reading to keep the blocks in sync
;
}
else {
pic[pici:] = stack[stacki+1:];
pici += nb;
}
fc = int stack[stacki+1];
if(first) {
first = 0;
continue;
}
early:=0; # peculiar tiff feature here for reference
if(nentry == maxentry-early) {
if(csize >= 12)
continue;
csize++;
maxentry = (1<<csize);
csmask = maxentry - 1;
if(csize < 12)
maxentry--;
}
tbl[nentry].prefix = ocode;
tbl[nentry].exten = fc;
nentry++;
}
}
while(pici < len pic) {
# shouldn't happen, but sometimes get buggy gifs
pic[pici++] = byte 0;
}
if(h.fields & INTERLACED) {
if(dbg)
sys->print("getgifmim uninterlacing\n");
if(dbgev)
CU->event("IMAGE_GETGIFMIM_INTERLACE_START", 0);
# (TODO: Could un-interlace in place.
# Decompose permutation into cycles,
# then need one double-copy of a line
# per cycle).
ipic := array[totpix] of byte;
# Group 1: every 8th row, starting with row 0
pici = 0;
ipici := 0;
ipiclim := totpix-width;
w2 := width+width;
w4 := w2+w2;
w8 := w4+w4;
startandby := array[4] of {(0,w8), (w4,w8), (w2,w4), (width,w2)};
for(k := 0; k < 4; k++) {
(start, by) := startandby[k];
for(ipici=start; ipici <= ipiclim; ipici += by) {
ipic[ipici:] = pic[pici:pici+width];
pici += width;
}
}
pic = ipic;
if(dbgev)
CU->event("IMAGE_GETGIFMIM_INTERLACE_END", 0);
}
if(is.width != is.origw || is.height != is.origh) {
if (is.width < 0)
is.width = 0;
if (is.height < 0)
is.height = 0;
# need to resample, using same factors as original image
wscale := real is.width / real is.origw;
hscale := real is.height / real is.origh;
owidth := width;
oheight := height;
width = int (wscale * real width);
if(width == 0)
width = 1;
height = int (hscale * real height);
if(height == 0)
height = 1;
left = int (wscale * real left);
top = int (hscale * real top);
pic = resample(pic, owidth, oheight, width, height);
}
mask : ref Image;
if(h.flags & TRANSP) {
if(dbg)
sys->print("getgifmim making mask, trindex=%d\n", int h.trindex);
if(dbgev)
CU->event("IMAGE_GETGIFMIM_MASK_START", 0);
# make a 1-bit deep bitmap for mask
# expect most mask bits will be 1
bytesperrow := (width+7)/8;
trpix := h.trindex;
mpic := array[bytesperrow*height] of byte;
mpici := 0;
pici = 0;
for(y := 0; y < height; y++) {
v := byte 16rFF;
k := 0;
for(x := 0; x < width; x++) {
if(pic[pici++] == trpix)
v &= ~(byte 16r80>>k);
if(++k == 8) {
k = 0;
mpic[mpici++] = v;
v = byte 16rFF;
}
}
if(k != 0)
mpic[mpici++] = v;
}
if(!(CU->imcache).need(bytesperrow*height))
imgerror(is, "out of memory");
mask = display.newimage(((0,0),(width,height)), D->GREY1, 0, D->Opaque);
if(mask == nil)
imgerror(is, "out of memory");
mask.writepixels(mask.r, mpic);
mpic = nil;
if(dbgev)
CU->event("IMAGE_GETGIFMIM_MASK_END", 0);
}
if(dbgev)
CU->event("IMAGE_GETGIFMIM_REMAP_START", 0);
pic24 := remap24(pic, h.cmap);
# remap1(pic, width, height, h.cmap);
if(dbgev)
CU->event("IMAGE_GETGIFMIM_REMAP_END", 0);
bgcolor := -1;
i := h.bgrnd;
if(i >= 0 && 3*i+2 < len h.cmap) {
bgcolor = ((int h.cmap[3*i])<<16)
| ((int h.cmap[3*i+1])<<8)
| (int h.cmap[3*i+2]);
}
im := newimage24(is, width, height);
im.writepixels(im.r, pic24);
if(is.curframe == 0) {
# make sure first frame fills up whole rectangle
if(is.width != width || is.height != height || left != 0 || top != 0) {
r := Rect((left,top),(left+width,top+height));
pix := D->White;
if(bgcolor != -1)
pix = (bgcolor<<8) | 16rFF;
newim := display.newimage(((0,0),(is.width,is.height)), D->RGB24, 0, pix);
if(newim == nil)
imgerror(is, "out of memory");
newim.draw(r, im, mask, (0,0));
im = newim;
if(mask != nil) {
newmask := display.newimage(((0,0),(is.width,is.height)), D->GREY1, 0, D->Opaque);
if(newmask == nil)
imgerror(is, "out of memory");
newmask.draw(r, mask, nil, (0,0));
mask = newmask;
}
left = 0;
top = 0;
}
}
pic = nil;
mi := newmi(im);
mi.mask = mask;
mi.delay = h.delay*10; # convert centiseconds to milliseconds
mi.origin = Point(left, top);
dispmeth := (h.flags>>2)&7;
if(dispmeth == 2) {
# reset to background color after displaying this frame
mi.bgcolor = bgcolor;
}
else if(dispmeth == 3) {
# Supposed to "reset to previous", which appears to
# mean the previous frame that didn't have a "reset to previous".
# Signal this special case to layout by setting bgcolor to -2.
mi.bgcolor = -2;
}
if(gifgettoimage(is)) {
mi.more = 1;
is.curframe++;
# have to reinitialize table for next time
for(i = 0; i < 258; i++) {
h.tbl[i].prefix = -1;
h.tbl[i].exten = i;
}
}
if(dbgev)
CU->event("IMAGE_GETGIFMIM_END", 0);
return mi;
}
# Read a GIF colormap, where bpe is number of bits in an entry.
# Raises a 'premature eof' exception if can't get the whole map.
gifreadcmap(is: ref ImageSource, bpe: int) : array of byte
{
size := 3*(1<<bpe);
map := array[size] of byte;
if(dbg > 1)
sys->print("gifreadcmap wants %d bytes\n", size);
read(is, map, size);
return map;
}
################# JPG ###################
# Constants, all preceded by byte 16rFF
SOF: con 16rC0; # Start of Frame
SOF2: con 16rC2; # Start of Frame; progressive Huffman
JPG: con 16rC8; # Reserved for JPEG extensions
DHT: con 16rC4; # Define Huffman Tables
DAC: con 16rCC; # Arithmetic coding conditioning
RST: con 16rD0; # Restart interval termination
RST7: con 16rD7; # Restart interval termination (highest value)
SOI: con 16rD8; # Start of Image
EOI: con 16rD9; # End of Image
SOS: con 16rDA; # Start of Scan
DQT: con 16rDB; # Define quantization tables
DNL: con 16rDC; # Define number of lines
DRI: con 16rDD; # Define restart interval
DHP: con 16rDE; # Define hierarchical progression
EXP: con 16rDF; # Expand reference components
APPn: con 16rE0; # Reserved for application segments
JPGn: con 16rF0; # Reserved for JPEG extensions
COM: con 16rFE; # Comment
NBUF: con 16*1024;
jpegcolorspace: con CYCbCr;
zerobytes := array[64] of { * => byte 0 };
zeroints := array[64] of { * => 0 };
getjpeghdr(is: ref ImageSource)
{
if(dbg)
sys->print("getjpeghdr\n");
h := ref Jpegstate(
0, 0, # sr, cnt
0, # Nf
nil, # comp
byte 0, # mode,
0, 0, # X, Y
nil, # qt
nil, nil, # dcht, acht
0, # Ns
nil, # scomp
0, 0, # Ss, Se
0, 0, # Ah, Al
0, 0, # ri, nseg
nil, # nblock
nil, nil, # dccoeff, accoeff
0, 0, 0, 0 # nacross, ndown, Hmax, Vmax
);
is.jstate = h;
if(jpegmarker(is) != SOI)
imgerror(is, "Jpeg expected SOI marker");
(m, n) := jpegtabmisc(is);
if(!(m == SOF || m == SOF2))
imgerror(is, "Jpeg expected Frame marker");
nil = getc(is); # sample precision
h.Y = getbew(is);
h.X = getbew(is);
h.Nf = getc(is);
if(dbg)
sys->print("start of frame, Y=%d, X=%d, Nf=%d\n", h.Y, h.X, h.Nf);
h.comp = array[h.Nf] of Framecomp;
h.nblock = array[h.Nf] of int;
for(i:=0; i<h.Nf; i++) {
h.comp[i].C = getc(is);
(H, V) := nibbles(getc(is));
h.comp[i].H = H;
h.comp[i].V = V;
h.comp[i].Tq = getc(is);
h.nblock[i] =H*V;
if(dbg)
sys->print("comp[%d]: C=%d, H=%d, V=%d, Tq=%d\n",
i, h.comp[i].C, H, V, h.comp[i].Tq);
}
h.mode = byte m;
is.origw = h.X;
is.origh = h.Y;
setdims(is);
if(n != 6+3*h.Nf)
imgerror(is, "Jpeg bad SOF length");
}
jpegmarker(is: ref ImageSource) : int
{
if(getc(is) != 16rFF)
imgerror(is, "Jpeg expected marker");
return getc(is);
}
# Consume tables and miscellaneous marker segments,
# returning the marker id and length of the first non-such-segment
# (after having consumed the marker).
# May raise "premature eof" or other exception.
jpegtabmisc(is: ref ImageSource) : (int, int)
{
h := is.jstate;
m, n : int;
Loop:
for(;;) {
h.nseg++;
m = jpegmarker(is);
n = 0;
if(m != EOI)
n = getbew(is) - 2;
if(dbg > 1)
sys->print("jpegtabmisc reading segment, got m=%x, n=%d\n", m, n);
case m {
SOF or SOF2 or SOS or EOI =>
break Loop;
APPn+0 =>
if(h.nseg==1 && n >= 6) {
(buf, i) := getn(is, 6);
n -= 6;
if(string buf[i:i+4]=="JFIF") {
vers0 := int buf[i+5];
vers1 := int buf[i+6];
if(vers0>1 || vers1>2)
imgerror(is, "Jpeg unimplemented version");
}
}
APPn+1 to APPn+15 =>
;
DQT =>
jpegquanttables(is, n);
n = 0;
DHT =>
jpeghuffmantables(is, n);
n = 0;
DRI =>
h.ri =getbew(is);
n -= 2;
COM =>
;
* =>
imgerror(is, "Jpeg unexpected marker");
}
if(n > 0)
getn(is, n);
}
return (m, n);
}
# Consume huffman tables, raising exception on error.
jpeghuffmantables(is: ref ImageSource, n: int)
{
if(dbg)
sys->print("jpeghuffmantables\n");
h := is.jstate;
if(h.dcht == nil) {
h.dcht = array[4] of ref Huffman;
h.acht = array[4] of ref Huffman;
}
for(l:= 0; l < n; )
l += jpeghuffmantable(is);
if(l != n)
imgerror(is, "Jpeg huffman table bad length");
}
jpeghuffmantable(is: ref ImageSource) : int
{
t := ref Huffman;
h := is.jstate;
(Tc, th) := nibbles(getc(is));
if(dbg > 1)
sys->print("jpeghuffmantable, Tc=%d, th=%d\n", Tc, th);
if(Tc > 1)
imgerror(is, "Jpeg unknown Huffman table class");
if(th>3 || (h.mode==byte SOF && th>1))
imgerror(is, "Jpeg unknown Huffman table index");
if(Tc == 0)
h.dcht[th] = t;
else
h.acht[th] = t;
# flow chart C-2
(b, bi) := getn(is, 16);
numcodes := array[16] of int;
nsize := 0;
for(i:=0; i<16; i++)
nsize += (numcodes[i] = int b[bi+i]);
t.size = array[nsize+1] of int;
k := 0;
for(i=1; i<=16; i++) {
n :=numcodes[i-1];
for(j:=0; j<n; j++)
t.size[k++] = i;
}
t.size[k] = 0;
# initialize HUFFVAL
t.val = array[nsize] of int;
(b, bi) = getn(is, nsize);
for(i=0; i<nsize; i++)
t.val[i] = int b[bi++];
# flow chart C-3
t.code = array[nsize+1] of int;
k = 0;
code := 0;
si := t.size[0];
for(;;) {
do
t.code[k++] = code++;
while(t.size[k] == si);
if(t.size[k] == 0)
break;
do {
code <<= 1;
si++;
} while(t.size[k] != si);
}
# flow chart F-25
t.mincode = array[17] of int;
t.maxcode = array[17] of int;
t.valptr = array[17] of int;
i = 0;
j := 0;
F25:
for(;;) {
for(;;) {
i++;
if(i > 16)
break F25;
if(numcodes[i-1] != 0)
break;
t.maxcode[i] = -1;
}
t.valptr[i] = j;
t.mincode[i] = t.code[j];
j += int numcodes[i-1]-1;
t.maxcode[i] = t.code[j];
j++;
}
# create byte-indexed fast path tables
t.value = array[256] of int;
t.shift = array[256] of int;
maxcode := t.maxcode;
# stupid startup algorithm: just run machine for each byte value
Bytes:
for(v:=0; v<256; v++){
cnt := 7;
m := 1<<7;
code = 0;
sr := v;
i = 1;
for(;;i++){
if(sr & m)
code |= 1;
if(code <= maxcode[i])
break;
code <<= 1;
m >>= 1;
if(m == 0){
t.shift[v] = 0;
t.value[v] = -1;
continue Bytes;
}
cnt--;
}
t.shift[v] = 8-cnt;
t.value[v] = t.val[t.valptr[i]+(code-t.mincode[i])];
}
if(dbg > 2) {
sys->print("Huffman table %d:\n", th);
printarray(t.size, "size");
printarray(t.code, "code");
printarray(t.val, "val");
printarray(t.mincode, "mincode");
printarray(t.maxcode, "maxcode");
printarray(t.value, "value");
printarray(t.shift, "shift");
}
return nsize+17;
}
jpegquanttables(is: ref ImageSource, n: int)
{
if(dbg)
sys->print("jpegquanttables\n");
h := is.jstate;
if(h.qt == nil)
h.qt = array[4] of array of int;
for(l:=0; l<n; )
l += jpegquanttable(is);
if(l != n)
imgerror(is, "Jpeg quant table bad length");
}
jpegquanttable(is: ref ImageSource): int
{
(pq, tq) := nibbles(getc(is));
if(dbg)
sys->print("jpegquanttable pq=%d tq=%d\n", pq, tq);
if(pq > 1)
imgerror(is, "Jpeg unknown quantization table class");
if(tq > 3)
imgerror(is, "Jpeg bad quantization table index");
q := array[64] of int;
is.jstate.qt[tq] = q;
for(i:=0; i<64; i++) {
if(pq == 0)
q[i] =getc(is);
else
q[i] = getbew(is);
}
if(dbg > 2)
printarray(q, "quant table");
return 1+(64*(1+pq));;
}
# Have just read Frame header.
# Now expect:
# ((tabl/misc segment(s))* (scan header) (entropy coded segment)+)+ EOI
getjpegmim(is: ref ImageSource) : ref MaskedImage
{
if(dbg)
sys->print("getjpegmim\n");
if(dbgev)
CU->event("IMAGE_GETJPGMIM", is.width*is.height);
getjpeghdr(is);
h := is.jstate;
chans: array of array of byte = nil;
for(;;) {
(m, n) := jpegtabmisc(is);
if(m == EOI)
break;
if(m != SOS)
imgerror(is, "Jpeg expected start of scan");
h.Ns = getc(is);
if(dbg)
sys->print("start of scan, Ns=%d\n", h.Ns);
scomp := array[h.Ns] of Scancomp;
for(i := 0; i < h.Ns; i++) {
scomp[i].C = getc(is);
(scomp[i].tdc, scomp[i].tac) = nibbles(getc(is));
}
h.scomp = scomp;
h.Ss = getc(is);
h.Se = getc(is);
(h.Ah, h.Al) = nibbles(getc(is));
if(n != 4+h.Ns*2)
imgerror(is, "Jpeg SOS header wrong length");
if(h.mode == byte SOF) {
if(chans != nil)
imgerror(is, "Jpeg baseline has > 1 scan");
chans = jpegbaselinescan(is);
}
else
jpegprogressivescan(is);
}
if(h.mode == byte SOF2)
chans = jprogressiveIDCT(is);
if(chans == nil)
imgerror(is, "jpeg has no image");
width := is.width;
height := is.height;
if(width != h.X || height != h.Y) {
for(k := 0; k < len chans; k++)
chans[k] = resample(chans[k], h.X, h.Y, width, height);
}
if(dbgev)
CU->event("IMAGE_JPG_REMAP", 0);
if(len chans == 1) {
im := newimagegrey(is, width, height);
im.writepixels(im.r, chans[0]);
return newmi(im);
# remapgrey(chans[0], width, height);
} else {
if (len chans == 3) {
r := remapYCbCr(chans);
im := newimage24(is, width, height);
im.writepixels(im.r, r);
return newmi(im);
}
remaprgb(chans, width, height, jpegcolorspace);
}
if(dbgev)
CU->event("IMAGE_JPG_REMAP_END", 0);
im := newimage(is, width, height);
im.writepixels(im.r, chans[0]);
if(dbgev)
CU->event("IMAGE_GETJPGMIM_END", 0);
return newmi(im);
}
remapYCbCr(chans: array of array of byte): array of byte
{
Y := chans[0];
Cb := chans[1];
Cr := chans[2];
rgb := array [3*len Y] of byte;
bix := 0;
for (i := 0; i < len Y; i++) {
y := int Y[i];
cb := int Cb[i];
cr := int Cr[i];
r := y + Cr2r[cr];
g := y - Cr2g[cr] - Cb2g[cb];
b := y + Cb2b[cb];
rgb[bix++] = clampb[b+CLAMPBOFF];
rgb[bix++] = clampb[g+CLAMPBOFF];
rgb[bix++] = clampb[r+CLAMPBOFF];
}
return rgb;
}
zig := array[64] of {
0, 1, 8, 16, 9, 2, 3, 10, 17, # 0-7
24, 32, 25, 18, 11, 4, 5, # 8-15
12, 19, 26, 33, 40, 48, 41, 34, # 16-23
27, 20, 13, 6, 7, 14, 21, 28, # 24-31
35, 42, 49, 56, 57, 50, 43, 36, # 32-39
29, 22, 15, 23, 30, 37, 44, 51, # 40-47
58, 59, 52, 45, 38, 31, 39, 46, # 48-55
53, 60, 61, 54, 47, 55, 62, 63 # 56-63
};
jpegbaselinescan(is: ref ImageSource) : array of array of byte
{
if(dbg)
sys->print("jpegbaselinescan\n");
if(dbgev)
CU->event("IMAGE_JPGBASELINESCAN", 0);
h := is.jstate;
Ns := h.Ns;
if(Ns != h.Nf)
imgerror(is, "Jpeg baseline needs Ns==Nf");
if(!(Ns==3 || Ns==1))
imgerror(is, "Jpeg baseline needs Ns==1 or 3");
res := ResourceState.cur();
heapavail := res.heaplim - res.heap;
# check heap availability for
# chans: (3+Ns)*4 + (Ns*(3*4+h.X*h.Y)) bytes
# Td, Ta, data, H, V, DC: 6 arrays of (3+Ns)*4 bytes
#
heapavail -= (3+Ns)*28 + (Ns*(12 + h.X * h.Y));
if(heapavail <= 0) {
if(dbg)
sys->print("jpegbaselinescan: no memory for chans et al.\n");
imgerror(is, "not enough memory");
}
chans := array[h.Nf] of array of byte;
for(k:=0; k<h.Nf; k++)
chans[k] = array[h.X*h.Y] of byte;
# build per-component arrays
Td := array[Ns] of int;
Ta := array[Ns] of int;
data := array[Ns] of array of array of int;
H := array[Ns] of int;
V := array[Ns] of int;
DC := array[Ns] of int;
# compute maximum H and V
Hmax := 0;
Vmax := 0;
for(comp:=0; comp<Ns; comp++) {
if(h.comp[comp].H > Hmax)
Hmax = h.comp[comp].H;
if(h.comp[comp].V > Vmax)
Vmax = h.comp[comp].V;
}
if(dbg > 1)
sys->print("Hmax=%d, Vmax=%d\n", Hmax, Vmax);
# initialize data structures
allHV1 := 1;
for(comp=0; comp<Ns; comp++) {
# JPEG requires scan components to be in same order as in frame,
# so if both have 3 we know scan is Y Cb Cr and there's no need to
# reorder
Td[comp] = h.scomp[comp].tdc;
Ta[comp] = h.scomp[comp].tac;
H[comp] = h.comp[comp].H;
V[comp] = h.comp[comp].V;
nblock := H[comp]*V[comp];
if(nblock != 1)
allHV1 = 0;
# data[comp]: needs (3+nblock)*4 + nblock*(3+8*8)*4 bytes
heapavail -= 272*nblock + 12;
if(heapavail <= 0){
if(dbg)
sys->print("jpegbaselinescan: no memory for data\n");
imgerror(is, "not enough memory");
}
data[comp] = array[nblock] of array of int;
DC[comp] = 0;
for(m:=0; m<nblock; m++)
data[comp][m] = array[8*8] of int;
if(dbg > 2)
sys->print("scan comp %d: H=%d, V=%d, nblock=%d, Td=%d, Ta=%d\n",
comp, H[comp], V[comp], nblock, Td[comp], Ta[comp]);
}
ri := h.ri;
h.cnt = 0;
h.sr = 0;
nacross := ((h.X+(8*Hmax-1))/(8*Hmax));
nmcu := ((h.Y+(8*Vmax-1))/(8*Vmax))*nacross;
if(dbg)
sys->print("nacross=%d, nmcu=%d\n", nacross, nmcu);
for(mcu:=0; mcu<nmcu; ) {
if(dbg > 2)
sys->print("mcu %d\n", mcu);
for(comp=0; comp<Ns; comp++) {
if(dbg > 2)
sys->print("comp %d\n", comp);
dcht := h.dcht[Td[comp]];
acht := h.acht[Ta[comp]];
qt := h.qt[h.comp[comp].Tq];
for(block:=0; block<H[comp]*V[comp]; block++) {
if(dbg > 2)
sys->print("block %d\n", block);
# F-22
t := jdecode(is, dcht);
diff := jreceive(is, t);
DC[comp] += diff;
if(dbg > 2)
sys->print("t=%d, diff=%d, DC=%d\n", t, diff, DC[comp]);
# F-23
zz := data[comp][block];
zz[0:] = zeroints;
zz[0] = qt[0]*DC[comp];
k = 1;
for(;;) {
rs := jdecode(is, acht);
(rrrr, ssss) := nibbles(rs);
if(ssss == 0){
if(rrrr != 15)
break;
k += 16;
}else{
k += rrrr;
z := jreceive(is, ssss);
zz[zig[k]] = z*qt[k];
if(k == 63)
break;
k++;
}
}
idct(zz);
}
}
# rotate colors to RGB and assign to bytes
if(Ns == 1) # very easy
colormap1(h, chans[0], data[0][0], mcu, nacross);
else if(allHV1) # fairly easy
colormapall1(h, chans, data[0][0], data[1][0], data[2][0], mcu, nacross);
else # miserable general case
colormap(h, chans, data[0], data[1], data[2], mcu, nacross, Hmax, Vmax, H, V);
# process restart marker, if present
mcu++;
if(ri>0 && mcu<nmcu && mcu%ri==0){
jrestart(is, mcu);
for(comp=0; comp<Ns; comp++)
DC[comp] = 0;
}
}
if(dbgev)
CU->event("IMAGE_JPGBASELINESCAN_END", 0);
return chans;
}
jrestart(is: ref ImageSource, mcu: int)
{
h := is.jstate;
ri := h.ri;
restart := mcu/ri-1;
rst, nskip: int;
nskip = 0;
do {
do{
rst = jnextborm(is);
nskip++;
}while(rst>=0 && rst!=16rFF);
if(rst == 16rFF){
rst = jnextborm(is);
nskip++;
}
} while(rst>=0 && (rst&~7)!= RST);
if(nskip != 2 || rst < 0 || ((rst&7) != (restart&7)))
imgerror(is, "Jpeg restart problem");
h.cnt = 0;
h.sr = 0;
}
jpegprogressivescan(is: ref ImageSource)
{
if(dbgev)
CU->event("IMAGE_JPGPROGSCAN", 0);
h := is.jstate;
if(h.dccoeff == nil)
jprogressiveinit(is, h);
c := h.scomp[0].C;
comp := -1;
for(i:=0; i<h.Nf; i++)
if(h.comp[i].C == c)
comp = i;
if(comp == -1)
imgerror(is, "Jpeg bad component index in scan header");
if(h.Ss == 0)
jprogressivedc(is, comp);
else if(h.Ah == 0)
jprogressiveac(is, comp);
else
jprogressiveacinc(is, comp);
if(dbgev)
CU->event("IMAGE_JPGPROGSCAN_END", 0);
}
jprogressiveIDCT(is: ref ImageSource): array of array of byte
{
if(dbgev)
CU->event("IMAGE_JPGPROGIDCT", 0);
h := is.jstate;
Nf := h.Nf;
res := ResourceState.cur();
heapavail := res.heaplim - res.heap;
# check heap availability for
# H, V, data, blockno: 4 arrays of (3+Nf)*4 bytes
# chans: (3+Nf)*4 + (Nf*(3*4+h.X*h.Y)) bytes
#
heapavail -= (3+Nf)*20 + (Nf*(12 + h.X * h.Y));
if(heapavail <= 0) {
if(dbg)
sys->print("jprogressiveIDCT: no memory for chans et al.\n");
imgerror(is, "not enough memory");
}
H := array[Nf] of int;
V := array[Nf] of int;
allHV1 := 1;
data := array[Nf] of array of array of int;
for(comp:=0; comp<Nf; comp++){
H[comp] = h.comp[comp].H;
V[comp] = h.comp[comp].V;
nblock := h.nblock[comp];
if(nblock != 1)
allHV1 = 0;
# data[comp]: needs (3+nblock)*4 + nblock*(3+8*8)*4 bytes
heapavail -= 272*nblock + 12;
if(heapavail <= 0){
if(dbg)
sys->print("jprogressiveIDCT: no memory for data\n");
imgerror(is, "not enough memory");
}
data[comp] = array[nblock] of array of int;
for(m:=0; m<nblock; m++)
data[comp][m] = array[8*8] of int;
}
chans := array[h.Nf] of array of byte;
for(k:=0; k<h.Nf; k++)
chans[k] = array[h.X*h.Y] of byte;
blockno := array[Nf] of {* => 0};
nmcu := h.nacross*h.ndown;
for(mcu:=0; mcu<nmcu; mcu++){
for(comp=0; comp<Nf; comp++){
dccoeff := h.dccoeff[comp];
accoeff := h.accoeff[comp];
bn := blockno[comp];
for(block:=0; block<h.nblock[comp]; block++){
zz := data[comp][block];
zz[0:] = zeroints;
zz[0] = dccoeff[bn];
for(k=1; k<64; k++)
zz[zig[k]] = accoeff[bn][k];
idct(zz);
bn++;
}
blockno[comp] = bn;
}
# rotate colors to RGB and assign to bytes
if(Nf == 1) # very easy
colormap1(h, chans[0], data[0][0], mcu, h.nacross);
else if(allHV1) # fairly easy
colormapall1(h, chans, data[0][0], data[1][0], data[2][0], mcu, h.nacross);
else # miserable general case
colormap(h, chans, data[0], data[1], data[2], mcu, h.nacross, h.Hmax, h.Vmax, H, V);
}
return chans;
}
jprogressiveinit(is: ref ImageSource, h: ref Jpegstate)
{
Ns := h.Ns;
Nf := h.Nf;
if((Ns!=3 && Ns!=1) || Ns!=Nf)
imgerror(is, "Jpeg image must have 1 or 3 components");
# compute maximum H and V
h.Hmax = 0;
h.Vmax = 0;
for(comp:=0; comp<Nf; comp++){
if(h.comp[comp].H > h.Hmax)
h.Hmax = h.comp[comp].H;
if(h.comp[comp].V > h.Vmax)
h.Vmax = h.comp[comp].V;
}
h.nacross = ((h.X+(8*h.Hmax-1))/(8*h.Hmax));
h.ndown = ((h.Y+(8*h.Vmax-1))/(8*h.Vmax));
nmcu := h.nacross*h.ndown;
res := ResourceState.cur();
heapavail := res.heaplim - res.heap;
# check heap availability for
# h.dccoeff: (3+Nf)*4 bytes
# h.accoeff: (3+Nf)*4 bytes
heapavail -= (3+Nf)*8;
if(heapavail <= 0) {
if(dbg)
sys->print("jprogressiveinit: no memory for coeffs\n");
imgerror(is, "not enough memory");
}
h.dccoeff = array[Nf] of array of int;
h.accoeff = array[Nf] of array of array of int;
for(k:=0; k<Nf; k++){
n := h.nblock[k]*nmcu;
# check heap availability for
# h.dccoeff[k]: (3+n)*4 bytes
# h.accoeff[k]: (3+n)*4 + n*(3+64)*4 bytes
heapavail -= 276*n + 24;
if(heapavail <= 0){
if(dbg)
sys->print("jprogressiveinit: no memory for coeff arrays\n");
imgerror(is, "not enough memory");
}
h.dccoeff[k] = array[n] of {* => 0};
h.accoeff[k] = array[n] of array of int;
for(j:=0; j<n; j++)
h.accoeff[k][j] = array[64] of {* => 0};
}
}
jprogressivedc(is: ref ImageSource, comp: int)
{
h := is.jstate;
Ns := h.Ns;
Ah := h.Ah;
Al := h.Al;
if(Ns!=h.Nf)
imgerror(is, "Jpeg progressive with Nf!=Ns in DC scan");
# build per-component arrays
Td := array[Ns] of int;
DC := array[Ns] of int;
# initialize data structures
h.cnt = 0;
h.sr = 0;
for(comp=0; comp<Ns; comp++) {
# JPEG requires scan components to be in same order as in frame,
# so if both have 3 we know scan is Y Cb Cr and there's no need to
# reorder
Td[comp] = h.scomp[comp].tdc;
DC[comp] = 0;
}
ri := h.ri;
nmcu := h.nacross*h.ndown;
blockno := array[Ns] of {* => 0};
for(mcu:=0; mcu<nmcu; ){
for(comp=0; comp<Ns; comp++){
dcht := h.dcht[Td[comp]];
qt := h.qt[h.comp[comp].Tq][0];
dc := h.dccoeff[comp];
bn := blockno[comp];
for(block:=0; block<h.nblock[comp]; block++) {
if(Ah == 0) {
t := jdecode(is, dcht);
diff := jreceive(is, t);
DC[comp] += diff;
dc[bn] = qt*DC[comp]<<Al;
} else
dc[bn] |= qt*jreceivebit(is)<<Al;
bn++;
}
blockno[comp] = bn;
}
# process restart marker, if present
mcu++;
if(ri>0 && mcu<nmcu && mcu%ri==0){
jrestart(is, mcu);
for(comp=0; comp<Ns; comp++)
DC[comp] = 0;
}
}
}
jprogressiveac(is: ref ImageSource, comp: int)
{
h := is.jstate;
Ns := h.Ns;
Al := h.Al;
if(Ns != 1)
imgerror(is, "Jpeg illegal Ns>1 in progressive AC scan");
Ss := h.Ss;
Se := h.Se;
H := h.comp[comp].H;
V := h.comp[comp].V;
nacross := h.nacross*H;
ndown := h.ndown*V;
q := 8*h.Hmax/H;
nhor := (h.X+q-1)/q;
q = 8*h.Vmax/V;
nver := (h.Y+q-1)/q;
# initialize data structures
h.cnt = 0;
h.sr = 0;
Ta := h.scomp[0].tac;
ri := h.ri;
eobrun := 0;
acht := h.acht[Ta];
qt := h.qt[h.comp[comp].Tq];
nmcu := nacross*ndown;
mcu := 0;
for(y:=0; y<nver; y++) {
for(x:=0; x<nhor; x++) {
# Figure G-3
if(eobrun > 0){
--eobrun;
continue;
}
# arrange blockno to be in same sequence as
# original scan calculation.
tmcu := x/H + (nacross/H)*(y/V);
blockno := tmcu*H*V + H*(y%V) + x%H;
acc := h.accoeff[comp][blockno];
k := Ss;
for(;;) {
rs := jdecode(is, acht);
(rrrr, ssss) := nibbles(rs);
if(ssss == 0) {
if(rrrr < 15) {
eobrun = 0;
if(rrrr > 0)
eobrun = jreceiveEOB(is, rrrr)-1;
break;
}
k += 16;
}
else {
k += rrrr;
z := jreceive(is, ssss);
acc[k] = z*qt[k]<<Al;
if(k == Se)
break;
k++;
}
}
}
# process restart marker, if present
mcu++;
if(ri>0 && mcu<nmcu && mcu%ri==0) {
jrestart(is, mcu);
eobrun = 0;
}
}
}
jprogressiveacinc(is: ref ImageSource, comp: int)
{
h := is.jstate;
Ns := h.Ns;
if(Ns != 1)
imgerror(is, "Jpeg illegal Ns>1 in progressive AC scan");
Ss := h.Ss;
Se := h.Se;
H := h.comp[comp].H;
V := h.comp[comp].V;
Al := h.Al;
nacross := h.nacross*H;
ndown := h.ndown*V;
q := 8*h.Hmax/H;
nhor := (h.X+q-1)/q;
q = 8*h.Vmax/V;
nver := (h.Y+q-1)/q;
# initialize data structures
h.cnt = 0;
h.sr = 0;
Ta := h.scomp[0].tac;
ri := h.ri;
eobrun := 0;
ac := h.accoeff[comp];
acht := h.acht[Ta];
qt := h.qt[h.comp[comp].Tq];
nmcu := nacross*ndown;
mcu := 0;
pending := 0;
nzeros := -1;
for(y:=0; y<nver; y++){
for(x:=0; x<nhor; x++){
# Figure G-7
# arrange blockno to be in same sequence as
# original scan calculation.
tmcu := x/H + (nacross/H)*(y/V);
blockno := tmcu*H*V + H*(y%V) + x%H;
acc := ac[blockno];
if(eobrun > 0){
if(nzeros > 0)
imgerror(is, "Jpeg zeros pending at block start");
for(k:=Ss; k<=Se; k++)
jincrement(is, acc, k, qt[k]<<Al);
--eobrun;
continue;
}
for(k:=Ss; k<=Se; ){
if(nzeros >= 0){
if(acc[k] != 0)
jincrement(is, acc, k, qt[k]<<Al);
else if(nzeros-- == 0)
acc[k] = pending;
k++;
continue;
}
rs := jdecode(is, acht);
(rrrr, ssss) := nibbles(rs);
if(ssss == 0){
if(rrrr < 15){
eobrun = 0;
if(rrrr > 0)
eobrun = jreceiveEOB(is, rrrr)-1;
while(k <= Se){
jincrement(is, acc, k, qt[k]<<Al);
k++;
}
break;
}
for(i:=0; i<16; k++){
jincrement(is, acc, k, qt[k]<<Al);
if(acc[k] == 0)
i++;
}
continue;
}else if(ssss != 1)
imgerror(is, "Jpeg ssss!=1 in progressive increment");
nzeros = rrrr;
pending = jreceivebit(is);
if(pending == 0)
pending = -1;
pending *= qt[k]<<Al;
}
}
# process restart marker, if present
mcu++;
if(ri>0 && mcu<nmcu && mcu%ri==0){
jrestart(is, mcu);
eobrun = 0;
nzeros = -1;
}
}
}
jincrement(is: ref ImageSource, acc: array of int, k, Pt: int)
{
if(acc[k] == 0)
return;
b := jreceivebit(is);
if(b != 0)
if(acc[k] < 0)
acc[k] -= Pt;
else
acc[k] += Pt;
}
jc1: con 2871; # 1.402 * 2048
jc2: con 705; # 0.34414 * 2048
jc3: con 1463; # 0.71414 * 2048
jc4: con 3629; # 1.772 * 2048
# Fills in pixels (x,y) for x = minx=8*(mcu%nacross), minx+1, ..., minx+7 (or h.X-1, if less)
# and for y = miny=8*(mcu/nacross), miny+1, ..., miny+7 (or h.Y-1, if less)
colormap1(h: ref Jpegstate, pic: array of byte, data: array of int, mcu, nacross: int)
{
minx := 8*(mcu%nacross);
dx := 8;
if(minx+dx > h.X)
dx = h.X-minx;
miny := 8*(mcu/nacross);
dy := 8;
if(miny+dy > h.Y)
dy = h.Y-miny;
pici := miny*h.X+minx;
k := 0;
for(y:=0; y<dy; y++) {
for(x:=0; x<dx; x++)
pic[pici+x] = clampb[(data[k+x]+128)+CLAMPBOFF];
pici += h.X;
k += 8;
}
}
# Fills in same pixels as colormap1
colormapall1(h: ref Jpegstate, chans: array of array of byte, data0, data1, data2: array of int, mcu, nacross: int)
{
rpic := chans[0];
gpic := chans[1];
bpic := chans[2];
minx := 8*(mcu%nacross);
dx := 8;
if(minx+dx > h.X)
dx = h.X-minx;
miny := 8*(mcu/nacross);
dy := 8;
if(miny+dy > h.Y)
dy = h.Y-miny;
pici := miny*h.X+minx;
k := 0;
for(y:=0; y<dy; y++) {
for(x:=0; x<dx; x++){
if(jpegcolorspace == CYCbCr) {
rpic[pici+x] = clampb[data0[k+x]+128+CLAMPBOFF];
gpic[pici+x] = clampb[data1[k+x]+128+CLAMPBOFF];
bpic[pici+x] = clampb[data2[k+x]+128+CLAMPBOFF];
}
else { # RGB
Y := (data0[k+x]+128) << 11;
Cb := data1[k+x];
Cr := data2[k+x];
r := Y+jc1*Cr;
g := Y-jc2*Cb-jc3*Cr;
b := Y+jc4*Cb;
rpic[pici+x] = clampb[(r>>11)+CLAMPBOFF];
gpic[pici+x] = clampb[(g>>11)+CLAMPBOFF];
bpic[pici+x] = clampb[(b>>11)+CLAMPBOFF];
}
}
pici += h.X;
k += 8;
}
}
# Fills in pixels (x,y) for x = minx=8*Hmax*(mcu%nacross), minx+1, ..., minx+8*Hmax-1 (or h.X-1, if less)
# and for y = miny=8*Vmax*(mcu/nacross), miny+1, ..., miny+8*Vmax-1 (or h.Y-1, if less)
colormap(h: ref Jpegstate, chans: array of array of byte, data0, data1, data2: array of array of int, mcu, nacross, Hmax, Vmax: int, H, V: array of int)
{
rpic := chans[0];
gpic := chans[1];
bpic := chans[2];
minx := 8*Hmax*(mcu%nacross);
dx := 8*Hmax;
if(minx+dx > h.X)
dx = h.X-minx;
miny := 8*Vmax*(mcu/nacross);
dy := 8*Vmax;
if(miny+dy > h.Y)
dy = h.Y-miny;
pici := miny*h.X+minx;
H0 := H[0];
H1 := H[1];
H2 := H[2];
if(dbg > 2)
sys->print("colormap, minx=%d, miny=%d, dx=%d, dy=%d, pici=%d, H0=%d, H1=%d, H2=%d\n",
minx, miny, dx, dy, pici, H0, H1, H2);
for(y:=0; y<dy; y++) {
t := y*V[0];
b0 := H0*(t/(8*Vmax));
y0 := 8*((t/Vmax)&7);
t = y*V[1];
b1 := H1*(t/(8*Vmax));
y1 := 8*((t/Vmax)&7);
t = y*V[2];
b2 := H2*(t/(8*Vmax));
y2 := 8*((t/Vmax)&7);
x0 := 0;
x1 := 0;
x2 := 0;
for(x:=0; x<dx; x++) {
if(jpegcolorspace == CYCbCr) {
rpic[pici+x] = clampb[data0[b0][y0+x0++*H0/Hmax] + 128 + CLAMPBOFF];
gpic[pici+x] = clampb[data1[b1][y1+x1++*H1/Hmax] + 128 + CLAMPBOFF];
bpic[pici+x] = clampb[data2[b2][y2+x2++*H2/Hmax] + 128 + CLAMPBOFF];
}
else { # RGB
Y := (data0[b0][y0+x0++*H0/Hmax]+128) << 11;
Cb := data1[b1][y1+x1++*H1/Hmax];
Cr := data2[b2][y2+x2++*H2/Hmax];
r := Y+jc1*Cr;
g := Y-jc2*Cb-jc3*Cr;
b := Y+jc4*Cb;
rpic[pici+x] = clampb[(r>>11)+CLAMPBOFF];
gpic[pici+x] = clampb[(g>>11)+CLAMPBOFF];
bpic[pici+x] = clampb[(b>>11)+CLAMPBOFF];
}
if(x0*H0/Hmax >= 8){
x0 = 0;
b0++;
}
if(x1*H1/Hmax >= 8){
x1 = 0;
b1++;
}
if(x2*H2/Hmax >= 8){
x2 = 0;
b2++;
}
}
pici += h.X;
}
}
# decode next 8-bit value from entropy-coded input. chart F-26
jdecode(is: ref ImageSource, t: ref Huffman): int
{
h := is.jstate;
maxcode := t.maxcode;
if(h.cnt < 8)
jnextbyte(is);
# fast lookup
code := (h.sr>>(h.cnt-8))&16rFF;
v := t.value[code];
if(v >= 0){
h.cnt -= t.shift[code];
return v;
}
h.cnt -= 8;
if(h.cnt == 0)
jnextbyte(is);
h.cnt--;
cnt := h.cnt;
m := 1<<cnt;
sr := h.sr;
code <<= 1;
i := 9;
for(;;i++){
if(sr & m)
code |= 1;
if(code <= maxcode[i])
break;
code <<= 1;
m >>= 1;
if(m == 0){
sr = jnextbyte(is);
m = 16r80;
cnt = 8;
}
cnt--;
}
h.cnt = cnt;
return t.val[t.valptr[i]+(code-t.mincode[i])];
}
# load next byte of input
jnextbyte(is: ref ImageSource): int
{
b :=getc(is);
if(b == 16rFF) {
b2 :=getc(is);
if(b2 != 0) {
if(b2 == int DNL)
imgerror(is, "Jpeg DNL marker unimplemented");
# decoder is reading into marker; satisfy it and restore state
ungetc2(is, byte b);
}
}
h := is.jstate;
h.cnt += 8;
h.sr = (h.sr<<8)| b;
return b;
}
# like jnextbyte, but look for marker too
jnextborm(is: ref ImageSource): int
{
b :=getc(is);
if(b == 16rFF)
return b;
h := is.jstate;
h.cnt += 8;
h.sr = (h.sr<<8)| b;
return b;
}
# return next s bits of input, MSB first, and level shift it
jreceive(is: ref ImageSource, s: int): int
{
h := is.jstate;
while(h.cnt < s)
jnextbyte(is);
h.cnt -= s;
v := h.sr >> h.cnt;
m := (1<<s);
v &= m-1;
# level shift
if(v < (m>>1))
v += ~(m-1)+1;
return v;
}
# return next s bits of input, decode as EOB
jreceiveEOB(is: ref ImageSource, s: int): int
{
h := is.jstate;
while(h.cnt < s)
jnextbyte(is);
h.cnt -= s;
v := h.sr >> h.cnt;
m := (1<<s);
v &= m-1;
# level shift
v += m;
return v;
}
# return next bit of input
jreceivebit(is: ref ImageSource): int
{
h := is.jstate;
if(h.cnt < 1)
jnextbyte(is);
h.cnt--;
return (h.sr >> h.cnt) & 1;
}
nibbles(c: int) : (int, int)
{
return (c>>4, c&15);
}
# Scaled integer implementation.
# inverse two dimensional DCT, Chen-Wang algorithm
# (IEEE ASSP-32, pp. 803-816, Aug. 1984)
# 32-bit integer arithmetic (8 bit coefficients)
# 11 mults, 29 adds per DCT
#
# coefficients extended to 12 bit for IEEE1180-1990
# compliance
W1: con 2841; # 2048*sqrt(2)*cos(1*pi/16)
W2: con 2676; # 2048*sqrt(2)*cos(2*pi/16)
W3: con 2408; # 2048*sqrt(2)*cos(3*pi/16)
W5: con 1609; # 2048*sqrt(2)*cos(5*pi/16)
W6: con 1108; # 2048*sqrt(2)*cos(6*pi/16)
W7: con 565; # 2048*sqrt(2)*cos(7*pi/16)
W1pW7: con 3406; # W1+W7
W1mW7: con 2276; # W1-W7
W3pW5: con 4017; # W3+W5
W3mW5: con 799; # W3-W5
W2pW6: con 3784; # W2+W6
W2mW6: con 1567; # W2-W6
R2: con 181; # 256/sqrt(2)
idct(b: array of int)
{
# transform horizontally
for(y:=0; y<8; y++){
eighty := y<<3;
# if all non-DC components are zero, just propagate the DC term
if(b[eighty+1]==0)
if(b[eighty+2]==0 && b[eighty+3]==0)
if(b[eighty+4]==0 && b[eighty+5]==0)
if(b[eighty+6]==0 && b[eighty+7]==0){
v := b[eighty]<<3;
b[eighty+0] = v;
b[eighty+1] = v;
b[eighty+2] = v;
b[eighty+3] = v;
b[eighty+4] = v;
b[eighty+5] = v;
b[eighty+6] = v;
b[eighty+7] = v;
continue;
}
# prescale
x0 := (b[eighty+0]<<11)+128;
x1 := b[eighty+4]<<11;
x2 := b[eighty+6];
x3 := b[eighty+2];
x4 := b[eighty+1];
x5 := b[eighty+7];
x6 := b[eighty+5];
x7 := b[eighty+3];
# first stage
x8 := W7*(x4+x5);
x4 = x8 + W1mW7*x4;
x5 = x8 - W1pW7*x5;
x8 = W3*(x6+x7);
x6 = x8 - W3mW5*x6;
x7 = x8 - W3pW5*x7;
# second stage
x8 = x0 + x1;
x0 -= x1;
x1 = W6*(x3+x2);
x2 = x1 - W2pW6*x2;
x3 = x1 + W2mW6*x3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
# third stage
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (R2*(x4+x5)+128)>>8;
x4 = (R2*(x4-x5)+128)>>8;
# fourth stage
b[eighty+0] = (x7+x1)>>8;
b[eighty+1] = (x3+x2)>>8;
b[eighty+2] = (x0+x4)>>8;
b[eighty+3] = (x8+x6)>>8;
b[eighty+4] = (x8-x6)>>8;
b[eighty+5] = (x0-x4)>>8;
b[eighty+6] = (x3-x2)>>8;
b[eighty+7] = (x7-x1)>>8;
}
# transform vertically
for(x:=0; x<8; x++){
# if all non-DC components are zero, just propagate the DC term
if(b[x+8*1]==0)
if(b[x+8*2]==0 && b[x+8*3]==0)
if(b[x+8*4]==0 && b[x+8*5]==0)
if(b[x+8*6]==0 && b[x+8*7]==0){
v := (b[x+8*0]+32)>>6;
b[x+8*0] = v;
b[x+8*1] = v;
b[x+8*2] = v;
b[x+8*3] = v;
b[x+8*4] = v;
b[x+8*5] = v;
b[x+8*6] = v;
b[x+8*7] = v;
continue;
}
# prescale
x0 := (b[x+8*0]<<8)+8192;
x1 := b[x+8*4]<<8;
x2 := b[x+8*6];
x3 := b[x+8*2];
x4 := b[x+8*1];
x5 := b[x+8*7];
x6 := b[x+8*5];
x7 := b[x+8*3];
# first stage
x8 := W7*(x4+x5) + 4;
x4 = (x8+W1mW7*x4)>>3;
x5 = (x8-W1pW7*x5)>>3;
x8 = W3*(x6+x7) + 4;
x6 = (x8-W3mW5*x6)>>3;
x7 = (x8-W3pW5*x7)>>3;
# second stage
x8 = x0 + x1;
x0 -= x1;
x1 = W6*(x3+x2) + 4;
x2 = (x1-W2pW6*x2)>>3;
x3 = (x1+W2mW6*x3)>>3;
x1 = x4 + x6;
x4 -= x6;
x6 = x5 + x7;
x5 -= x7;
# third stage
x7 = x8 + x3;
x8 -= x3;
x3 = x0 + x2;
x0 -= x2;
x2 = (R2*(x4+x5)+128)>>8;
x4 = (R2*(x4-x5)+128)>>8;
# fourth stage
b[x+8*0] = (x7+x1)>>14;
b[x+8*1] = (x3+x2)>>14;
b[x+8*2] = (x0+x4)>>14;
b[x+8*3] = (x8+x6)>>14;
b[x+8*4] = (x8-x6)>>14;
b[x+8*5] = (x0-x4)>>14;
b[x+8*6] = (x3-x2)>>14;
b[x+8*7] = (x7-x1)>>14;
}
}
################# Remap colors and Dither ##############
closest_rgbpix(r, g, b: int) : int
{
pix := int closestrgb[((r>>4)<<8)+((g>>4)<<4)+(b>>4)];
# If white is the closest but original r,g,b wasn't white,
# look for another color, because web page designer probably
# cares more about contrast than actual color
if(pix == 0 && !(r == 255 && g ==255 && b == 255)) {
bestdist := 1000000;
for(i := 1; i < 256; i++) {
dr := r-rgbvmap_r[i];
dg := g-rgbvmap_g[i];
db := b-rgbvmap_b[i];
d := dr*dr + dg*dg + db*db;
if(d < bestdist) {
bestdist = d;
pix = i;
}
}
}
return pix;
}
CLAMPBOFF: con 300;
NCLAMPB: con CLAMPBOFF+256+CLAMPBOFF;
CLAMPNOFF: con 64;
NCLAMPN: con CLAMPNOFF+256+CLAMPNOFF;
clampb: array of byte; # clamps byte values
clampn_b: array of int; # clamps byte values, then shifts >> 4
clampn_g: array of int; # clamps byte values, then masks off lower 4 bits
clampn_r: array of int; # clamps byte values, masks off lower 4 bits, then shifts <<4
init_tabs()
{
clampn_b = array[NCLAMPN] of int;
clampn_g = array[NCLAMPN] of int;
clampn_r = array[NCLAMPN] of int;
for(j:=0; j<CLAMPNOFF; j++) {
clampn_b[j] = 0;
clampn_g[j] = 0;
clampn_r[j] = 0;
}
for(j=0; j<256; j++) {
t := j>>4;
clampn_b[CLAMPNOFF+j] = t;
clampn_g[CLAMPNOFF+j] = t<<4;
clampn_r[CLAMPNOFF+j] = t<<8;
}
for(j=0; j<CLAMPNOFF; j++) {
clampn_b[CLAMPNOFF+256+j] = 16r0F;
clampn_g[CLAMPNOFF+256+j] = 16rF0;
clampn_r[CLAMPNOFF+256+j] = 16rF00;
}
clampb = array[NCLAMPB] of byte;
for(j=0; j<CLAMPBOFF; j++)
clampb[j] = byte 0;
for(j=0; j<256; j++)
clampb[CLAMPBOFF+j] = byte j;
for(j=0; j<CLAMPBOFF; j++)
clampb[CLAMPBOFF+256+j] = byte 16rFF;
}
# could account for mask in alpha rather than having separate mask
remap24(pic: array of byte, cmap: array of byte): array of byte
{
cmap_r := array[256] of byte;
cmap_g := array[256] of byte;
cmap_b := array[256] of byte;
i := 0;
for(j := 0; j < 256 && i < len cmap; j++) {
cmap_r[j] = cmap[i++];
cmap_g[j] = cmap[i++];
cmap_b[j] = cmap[i++];
}
# in case input has bad indices
for( ; j < 256; j++) {
cmap_r[j] = byte 0;
cmap_g[j] = byte 0;
cmap_b[j] = byte 0;
}
pic24 := array [3 * len pic] of byte;
ix24 := 0;
for (i = 0; i < len pic; i++) {
c := int pic[i];
pic24[ix24++] = cmap_b[c];
pic24[ix24++] = cmap_g[c];
pic24[ix24++] = cmap_r[c];
}
return pic24;
}
# Remap pixels of pic[] into the closest colors in the rgbv map,
# and do error diffusion of the result.
# pic is a one-channel image whose rgb values are given by looking
# up values in cmap.
remap1(pic: array of byte, dx, dy: int, cmap: array of byte)
{
if(dbg)
sys->print("remap1, pic len %d, dx=%d, dy=%d\n", len pic, dx, dy);
cmap_r := array[256] of int;
cmap_g := array[256] of int;
cmap_b := array[256] of int;
i := 0;
for(j := 0; j < 256 && i < len cmap; j++) {
cmap_r[j] = int cmap[i++];
cmap_g[j] = int cmap[i++];
cmap_b[j] = int cmap[i++];
}
# in case input has bad indices
for( ; j < 256; j++) {
cmap_r[j] = 0;
cmap_g[j] = 0;
cmap_b[j] = 0;
}
# modified floyd steinberg, coefficients (1 0) 3/16, (0, 1) 3/16, (1, 1) 7/16
ered := array[dx+1] of { * => 0 };
egrn := array[dx+1] of int;
eblu := array[dx+1] of int;
egrn[0:] = ered;
eblu[0:] = ered;
p := 0;
for(y:=0; y<dy; y++) {
er := 0;
eg := 0;
eb := 0;
for(x:=0; x<dx; ) {
x1 := x+1;
in := int pic[p];
r := cmap_r[in]+ered[x];
g := cmap_g[in]+egrn[x];
b := cmap_b[in]+eblu[x];
col := int (closestrgb[clampn_r[r+CLAMPNOFF]
+clampn_g[g+CLAMPNOFF]
+clampn_b[b+CLAMPNOFF]]);
pic[p++] = byte 255 - byte col;
r -= rgbvmap_r[col];
t := (3*r)>>4;
ered[x] = t+er;
ered[x1] += t;
er = r-3*t;
g -= rgbvmap_g[col];
t = (3*g)>>4;
egrn[x] = t+eg;
egrn[x1] += t;
eg = g-3*t;
b -= rgbvmap_b[col];
t = (3*b)>>4;
eblu[x] = t+eb;
eblu[x1] += t;
eb = b-3*t;
x = x1;
}
}
}
# Remap pixels of pic[] into the closest greyscale colors in the rgbv map,
# and do error diffusion of the result.
# pic is a one-channel greyscale image.
remapgrey(pic: array of byte, dx, dy: int)
{
if(dbg)
sys->print("remapgrey, pic len %d, dx=%d, dy=%d\n", len pic, dx, dy);
# modified floyd steinberg, coefficients (1 0) 3/16, (0, 1) 3/16, (1, 1) 7/16
e := array[dx+1] of {* => 0 };
p := 0;
for(y:=0; y<dy; y++){
eb := 0;
for(x:=0; x<dx; ) {
x1 := x+1;
b := int pic[p]+e[x];
b1 := clampn_b[b+CLAMPNOFF];
col := 255-17*b1;
pic[p++] = byte col;
b -= rgbvmap_b[col];
t := (3*b)>>4;
e[x] = t+eb;
e[x1] += t;
eb = b-3*t;
x = x1;
}
}
}
# Remap pixels of chans into the closest colors in the rgbv map,
# and do error diffusion of the result.
# chans is a 3-channel image whose channels are either (y,cb,cr) or
# (r,g,b), depending on whether colorspace is CYCbCr or CRGB.
# Variable names use r,g,b (historical).
remaprgb(chans: array of array of byte, dx, dy, colorspace: int)
{
if(dbg)
sys->print("remaprgb, pic len %d, dx=%d, dy=%d\n", len chans[0], dx, dy);
rpic := chans[0];
gpic := chans[1];
bpic := chans[2];
pic := chans[0];
# modified floyd steinberg, coefficients (1 0) 3/16, (0, 1) 3/16, (1, 1) 7/16
ered := array[dx+1] of { * => 0 };
egrn := array[dx+1] of int;
eblu := array[dx+1] of int;
egrn[0:] = ered;
eblu[0:] = ered;
closest: array of byte;
map0, map1, map2: array of int;
if(colorspace == CRGB) {
closest = closestrgb;
map0 = rgbvmap_r;
map1 = rgbvmap_g;
map2 = rgbvmap_b;
}
else {
closest = closestycbcr;
map0 = rgbvmap_y;
map1 = rgbvmap_cb;
map2 = rgbvmap_cr;
}
p := 0;
for(y:=0; y<dy; y++ ) {
er := 0;
eg := 0;
eb := 0;
for(x:=0; x<dx; ) {
x1 := x + 1;
r := int rpic[p]+ered[x];
g := int gpic[p]+egrn[x];
b := int bpic[p]+eblu[x];
# Errors can be uncorrectable if converting from YCbCr,
# since we can't guarantee that an extremal value of one of
# the components selects a color with an extremal value.
# If we don't, the errors accumulate without bound. This
# doesn't happen in RGB because the closest table can guarantee
# a color on the edge of the gamut, producing a zero error in
# that component. For the rotation YCbCr space, there may be
# no color that can guarantee zero error at the edge.
# Therefore we must clamp explicitly rather than by assuming
# an upper error bound of CLAMPOFF. The performance difference
# is miniscule anyway.
if(r < 0)
r = 0;
else if(r > 255)
r = 255;
if(g < 0)
g = 0;
else if(g > 255)
g = 255;
if(b < 0)
b = 0;
else if(b > 255)
b = 255;
col := int (closest[(b>>4)+16*((g>>4)+(r&16rF0))]);
pic[p++] = byte (255-col);
# col := int (pic[p++] = closest[(b>>4)+16*((g>>4)+16*(r>>4))]);
r -= map0[col];
t := (3*r)>>4;
ered[x] = t+er;
ered[x1] += t;
er = r-3*t;
g -= map1[col];
t = (3*g)>>4;
egrn[x] = t+eg;
egrn[x1] += t;
eg = g-3*t;
b -= map2[col];
t = (3*b)>>4;
eblu[x] = t+eb;
eblu[x1] += t;
eb = b-3*t;
x = x1;
}
}
}
# Given src array, representing sw*sh pixel values, resample them into
# the returned array, with dimensions dw*dh.
#
# Quick and dirty resampling: just interpolate.
# This lets us resample arrays of pixels indices (e.g., result of gif decoding).
# The filter-based resampling methods need conversion to rgb or grayscale.
# Also, although the results won't look good, people really shouldn't be
# asking the browser to resample except for special purposes (like the common
# case of resizing a 1x1 image to make a spacer).
resample(src: array of byte, sw, sh: int, dw, dh: int) : array of byte
{
if(dbgev)
CU->event("IMAGE_RESAMPLE_START", 0);
if(src == nil || sw == 0 || sh == 0 || dw == 0 || dh == 0)
return src;
xfac := real sw / real dw;
yfac := real sh / real dh;
totpix := dw*dh;
dst := array[totpix] of byte;
dindex := 0;
# precompute index in src row corresponding to each index in dst row
sindices := array[dw] of int;
dx := 0.0;
for(x := 0; x < dw; x++) {
sx := int dx;
dx += xfac;
if(sx >= sw)
sx = sw-1;
sindices[x] = sx;
}
dy := 0.0;
for(y := 0; y < dh; y++) {
sy := int dy;
dy += yfac;
if(sy >= sh)
sy = sh-1;
soffset := sy * sw;
for(x = 0; x < dw; x++)
dst[dindex++] = src[soffset + sindices[x]];
}
if(dbgev)
CU->event("IMAGE_RESAMPLE_END", 0);
return dst;
}
################# BIT ###################
getbitmim(is: ref ImageSource) : ref MaskedImage
{
if(dbg)
sys->print("img getbitmim: w=%d h=%d len=%d\n",
is.width, is.height, len is.bs.data);
im := getbitimage(is, display, is.bs.data);
if(im == nil)
imgerror(is, "out of memory");
is.i = is.bs.edata; # getbitimage should do this too!
is.width = im.r.max.x;
is.height = im.r.max.y;
return newmi(im);
}
NMATCH: con 3; # shortest match possible
NCBLOCK: con 6000; # size of compressed blocks
drawld2chan := array[] of {
0 => Draw->GREY1,
1 => Draw->GREY2,
2 => Draw->GREY4,
3 => Draw->CMAP8
};
getbitimage(is: ref ImageSource, disp: ref Display, d: array of byte): ref Image
{
compressed := 0;
if(len d < 5*12)
imgerror(is, "bad bit format");
if(string d[:11] == "compressed\n"){
if(dbg)
sys->print("img: bit compressed\n");
compressed = 1;
d = d[11:];
}
#
# distinguish new channel descriptor from old ldepth.
# channel descriptors have letters as well as numbers,
# while ldepths are a single digit formatted as %-11d
#
new := 0;
for(m := 0; m < 10; m++){
if(d[m] != byte ' '){
new = 1;
break;
}
}
if(d[11] != byte ' ')
imgerror(is, "bad bit format");
chans: Chans;
if(new){
s := string d[0:11];
chans = Chans.mk(s);
if(chans.desc == 0)
imgerror(is, sys->sprint("bad channel string %s", s));
}else{
ld := int( d[10] - byte '0' );
if(ld < 0 || ld > 3)
imgerror(is, "bad bit ldepth");
chans = drawld2chan[ld];
}
xmin := int string d[ 1*12 : 2*12 ];
ymin := int string d[ 2*12 : 3*12 ];
xmax := int string d[ 3*12 : 4*12 ];
ymax := int string d[ 4*12 : 5*12 ];
if( (xmin > xmax) || (ymin > ymax) )
imgerror(is, "bad bit rectangle");
if(dbg)
sys->print("img: bit: chans=%s, xmin=%d, ymin=%d, xmax=%d, ymax=%d\n",
chans.text(), xmin, ymin, xmax, ymax);
r := Rect( (xmin, ymin), (xmax, ymax) );
im := disp.newimage(r, chans, 0, D->Black);
if(im == nil)
return nil;
if (!compressed){
if(!new)
for(j:=5*12; j<len d; j++)
d[j] ^= byte 16rFF;
im.writepixels(im.r, d[5*12:]);
return im;
}
# see /libdraw/readimage.c, /libdraw/creadimage.c, and
# /libmemdraw/cload.c for reference implementation
# of bit compression
bpl := D->bytesperline(r, im.depth);
a := array[(ymax-ymin)*bpl] of byte;
ai := 0; #index into uncompressed data array a
di := 5*12; #index into compressed data
while(ymin < ymax){
y := int string d[ di : di + 1*12 ];
n := int string d[ di + 1*12 : di + 2*12 ];
di += 2*12;
if (y <= ymin || ymax < y)
imgerror(is, "bad compressed bit y-max");
if (n <= 0 || NCBLOCK < n)
imgerror(is, "bad compressed bit count");
# no input-stream error checking :-(
u := di;
while(di < u+n){
c := int d[di++];
if (c >= 128){
# copy as is
cnt := c-128 + 1;
# check for overrun of index di within d?
a[ai:] = d[di:di+cnt];
if(!new)
for(j:=0; j<cnt; j++)
a[ai+j] ^= byte 16rFF;
di += cnt;
ai += cnt;
}
else {
# copy a run/match
offs := int(d[di++]) + ((c&3)<<8) + 1;
cnt := (c>>2) + NMATCH;
# simply: a[ai:ai+cnt] = a[ai-offs:ai-offs+cnt];
for(i:=0; i<cnt; i++)
a[ai+i] = a[ai-offs+i];
ai += cnt;
}
}
ymin = y;
}
im.writepixels(im.r, a);
return im;
}
################# PNG ###################
Rawimage: adt {
r: Draw->Rect;
cmap: array of byte;
transp: int; # transparency flag (only for nchans=1)
trindex: byte; # transparency index
nchans: int;
chans: array of array of byte;
chandesc:int;
fields: int; # defined by format
};
Chunk: adt {
size : int;
typ: string;
crc_state: ref CRCstate;
};
Png: adt {
depth: int;
filterbpp: int;
colortype: int;
compressionmethod: int;
filtermethod: int;
interlacemethod: int;
# tRNS
PLTEsize: int;
tRNS: array of byte;
# state for managing unpacking
alpha: int;
done: int;
error: string;
row, rowstep, colstart, colstep: int;
phase: int;
phasecols: int;
phaserows: int;
rowsize: int;
rowbytessofar: int;
thisrow: array of byte;
lastrow: array of byte;
};
# currently do not support transparency
# hence no mask is set
#
# need to re-jig this code
# for example there is no point in mapping up a 2 or 4 bit greyscale image
# to 8 bit luminance to then remap it to the inferno palette when
# the draw device will do that for us anyway!
getpngmim(is: ref ImageSource) : ref MaskedImage
{
chunk := ref Chunk;
png := ref Png;
raw := ref Rawimage;
chunk.crc_state = crc->init(0, int 16rffffffff);
# Check it's a PNG
if (!png_signature(is))
imgerror(is, "PNG not a PNG");
# Get the IHDR
if (!png_chunk_header(is, chunk))
imgerror(is, "PNG duff header");
if (chunk.typ != "IHDR")
imgerror(is, "PNG IHDR must come first");
if (chunk.size != 13)
imgerror(is, "PNG IHDR wrong size");
raw.r.max.x = png_int(is, chunk.crc_state);
if (raw.r.max.x <= 0)
imgerror(is, "PNG invalid width");
raw.r.max.y = png_int(is, chunk.crc_state);
if (raw.r.max.y <= 0)
imgerror(is, "PNG invalid height");
png.depth = png_byte(is, chunk.crc_state);
case png.depth {
1 or 2 or 4 or 8 or 16 =>
;
* =>
imgerror(is, "PNG invalid depth");
}
png.colortype = png_byte(is, chunk.crc_state);
okcombo : int;
case png.colortype {
0 =>
okcombo = 1;
raw.nchans = 1;
raw.chandesc = CY;
png.alpha = 0;
2 =>
okcombo = (png.depth == 8 || png.depth == 16);
raw.nchans = 3;
raw.chandesc = CRGB;
png.alpha = 0;
3 =>
okcombo = (png.depth != 16);
raw.nchans = 1;
raw.chandesc = CRGB1;
png.alpha = 0;
4 =>
okcombo = (png.depth == 8 || png.depth == 16);
raw.nchans = 1;
raw.chandesc = CY;
png.alpha = 1;
6 =>
okcombo = (png.depth == 8 || png.depth == 16);
raw.nchans = 3;
raw.chandesc = CRGB;
png.alpha = 1;
* =>
imgerror(is, "PNG invalid colortype");
}
if (!okcombo)
imgerror(is, "PNG invalid depth/colortype combination");
png.compressionmethod = png_byte(is, chunk.crc_state);
if (png.compressionmethod != 0)
imgerror(is, "PNG invalid compression method " + string png.compressionmethod);
png.filtermethod = png_byte(is, chunk.crc_state);
if (png.filtermethod != 0)
imgerror(is, "PNG invalid filter method");
png.interlacemethod = png_byte(is, chunk.crc_state);
if (png.interlacemethod != 0 && png.interlacemethod != 1)
imgerror(is, "PNG invalid interlace method");
# sys->print("width %d height %d depth %d colortype %d interlace %d\n",
# raw.r.max.x, raw.r.max.y, png.depth, png.colortype, png.interlacemethod);
if (!png_crc_and_check(is, chunk))
imgerror(is, "PNG invalid CRC");
# Stash some detail in raw
raw.r.min = Point(0, 0);
raw.transp = 0;
raw.chans = array[raw.nchans] of array of byte;
{
for (r:= 0; r < raw.nchans; r++)
raw.chans[r] = array[raw.r.max.x * raw.r.max.y] of byte;
}
# Get the next chunk
seenPLTE := 0;
seenIDAT := 0;
seenLastIDAT := 0;
inflateFinished := 0;
seenIEND := 0;
seentRNS := 0;
rq: chan of ref Filter->Rq;
png.error = nil;
rq = nil;
while (png.error == nil) {
if (!png_chunk_header(is, chunk)) {
if (!seenIEND)
png.error = "duff header";
break;
}
if (seenIEND) {
png.error = "rubbish at eof";
break;
}
case (chunk.typ) {
"IEND" =>
seenIEND = 1;
"PLTE" =>
if (seenPLTE) {
png.error = "too many PLTEs";
break;
}
if (seentRNS) {
png.error = "tRNS before PLTE";
break;
}
if (seenIDAT) {
png.error = "PLTE too late";
break;
}
if (chunk.size % 3 || chunk.size < 1 * 3 || chunk.size > 256 * 3) {
png.error = "PLTE strange size";
break;
}
if (png.colortype == 0 || png.colortype == 4) {
png.error = "superfluous PLTE";
break;
}
raw.cmap = array[256 * 3] of byte;
png.PLTEsize = chunk.size / 3;
if (!png_bytes(is, chunk.crc_state, raw.cmap, chunk.size)) {
png.error = "eof in PLTE";
break;
}
# {
# x: int;
# sys->print("Palette:\n");
# for (x = 0; x < chunk.size; x += 3)
# sys->print("%3d: (%3d, %3d, %3d)\n",
# x / 3, int raw.cmap[x], int raw.cmap[x + 1], int raw.cmap[x + 2]);
# }
seenPLTE = 1;
"tRNS" =>
if (seenIDAT) {
png.error = "tRNS too late";
break;
}
case png.colortype {
0 =>
if (chunk.size != 2) {
png.error = "tRNS wrong size";
break;
}
level := png_ushort(is, chunk.crc_state);
if (level < 0) {
png.error = "eof in tRNS";
break;
}
if (png.depth != 16) {
raw.transp = 1;
raw.trindex = byte level;
}
2 =>
# a legitimate coding, but we can't use the information
if (!png_skip_bytes(is, chunk.crc_state, chunk.size))
png.error = "eof in skipped tRNS chunk";
break;
3 =>
if (!seenPLTE) {
png.error = "tRNS too early";
break;
}
if (chunk.size > png.PLTEsize) {
png.error = "tRNS too big";
break;
}
png.tRNS = array[png.PLTEsize] of byte;
for (x := chunk.size; x < png.PLTEsize; x++)
png.tRNS[x] = byte 255;
if (!png_bytes(is, chunk.crc_state, png.tRNS, chunk.size)) {
png.error = "eof in tRNS";
break;
}
# {
# sys->print("tRNS:\n");
# for (x = 0; x < chunk.size; x++)
# sys->print("%3d: (%3d)\n", x, int png.tRNS[x]);
# }
if (png.error == nil) {
# analyse the tRNS chunk to see if it contains a single transparent index
# translucent entries are treated as opaque
for (x = 0; x < chunk.size; x++)
if (png.tRNS[x] == byte 0) {
raw.trindex = byte x;
if (raw.transp) {
raw.transp = 0;
break;
}
raw.transp = 1;
}
# if (raw.transp)
# sys->print("selected index %d\n", int raw.trindex);
}
4 or 6 =>
png.error = "tRNS invalid when alpha present";
}
seentRNS = 1;
"IDAT" =>
if (seenLastIDAT) {
png.error = "non contiguous IDATs";
break;
}
if (inflateFinished) {
png.error = "too many IDATs";
break;
}
remaining := 0;
if (!seenIDAT) {
# open channel to inflate filter
if (!processdatainit(png, raw))
break;
rq = inflate->start(nil);
png_skip_bytes(is, chunk.crc_state, 2);
remaining = chunk.size - 2;
}
else
remaining = chunk.size;
while (remaining && png.error == nil) {
pick m := <- rq {
Fill =>
# sys->print("Fill(%d) remaining %d\n", len m.buf, remaining);
toget := len m.buf;
if (toget > remaining)
toget = remaining;
if (!png_bytes(is, chunk.crc_state, m.buf, toget)) {
m.reply <-= -1;
png.error = "eof during IDAT";
break;
}
m.reply <-= toget;
remaining -= toget;
Result =>
# sys->print("Result(%d)\n", len m.buf);
m.reply <-= 0;
processdata(png, raw, m.buf);
Info =>
# sys->print("Info(%s)\n", m.msg);
Finished =>
inflateFinished = 1;
# sys->print("Finished\n");
Error =>
imgerror(is, "PNG inflate error\n");
}
}
seenIDAT = 1;
* =>
# skip the blighter
if (!png_skip_bytes(is, chunk.crc_state, chunk.size))
png.error = "eof in skipped chunk";
}
if (png.error != nil)
break;
if (!png_crc_and_check(is, chunk))
imgerror(is, "PNG invalid CRC");
if (chunk.typ != "IDAT" && seenIDAT)
seenLastIDAT = 1;
}
# can only get here if IEND was last chunk, or png.error set
if (png.error == nil && !seenIDAT) {
png.error = "no IDAT!";
inflateFinished = 1;
}
while (rq != nil && !inflateFinished) {
pick m := <-rq {
Fill =>
# sys->print("Fill(%d)\n", len m.buf);
png.error = "eof in zlib stream";
m.reply <-= -1;
inflateFinished = 1;
Result =>
# sys->print("Result(%d)\n", len m.buf);
if (png.error != nil) {
m.reply <-= -1;
inflateFinished = 1;
}
else {
m.reply <-= 0;
processdata(png, raw, m.buf);
}
Info =>
# sys->print("Info(%s)\n", m.msg);
Finished =>
# sys->print("Finished\n");
inflateFinished = 1;
break;
Error =>
png.error = "inflate error\n";
inflateFinished = 1;
}
}
if (png.error == nil && !png.done)
png.error = "insufficient data";
if (png.error != nil)
imgerror(is, "PNG " + png.error);
width := raw.r.dx();
height := raw.r.dy();
case raw.chandesc {
CY =>
remapgrey(raw.chans[0], width, height);
CRGB =>
remaprgb(raw.chans, width, height, CRGB);
CRGB1 =>
remap1(raw.chans[0], width, height, raw.cmap);
}
pixels := raw.chans[0];
is.origw = width;
is.origh = height;
setdims(is);
if(is.width != is.origw || is.height != is.origh)
pixels = resample(pixels, is.origw, is.origh, is.width, is.height);
im := newimage(is, is.width, is.height);
im.writepixels(im.r, pixels);
mi := newmi(im);
# mi.mask = display.newimage(im.r, D->GREY1, 0, D->Black);
return mi;
}
phase2stepping(phase: int): (int, int, int, int)
{
case phase {
0 =>
return (0, 1, 0, 1);
1 =>
return (0, 8, 0, 8);
2 =>
return (0, 8, 4, 8);
3 =>
return (4, 8, 0, 4);
4 =>
return (0, 4, 2, 4);
5 =>
return (2, 4, 0, 2);
6 =>
return (0, 2, 1, 2);
7 =>
return (1, 2, 0, 1);
* =>
return (-1, -1, -1, -1);
}
}
processdatainitphase(png: ref Png, raw: ref Rawimage)
{
(png.row, png.rowstep, png.colstart, png.colstep) = phase2stepping(png.phase);
if (raw.r.max.x > png.colstart)
png.phasecols = (raw.r.max.x - png.colstart + png.colstep - 1) / png.colstep;
else
png.phasecols = 0;
if (raw.r.max.y > png.row)
png.phaserows = (raw.r.max.y - png.row + png.rowstep - 1) / png.rowstep;
else
png.phaserows = 0;
png.rowsize = png.phasecols * (raw.nchans + png.alpha) * png.depth;
png.rowsize = (png.rowsize + 7) / 8;
png.rowsize++; # for the filter byte
png.rowbytessofar = 0;
png.thisrow = array[png.rowsize] of byte;
png.lastrow = array[png.rowsize] of byte;
# sys->print("init phase %d: r (%d, %d, %d) c (%d, %d, %d) (%d)\n",
# png.phase, png.row, png.rowstep, png.phaserows,
# png.colstart, png.colstep, png.phasecols, png.rowsize);
}
processdatainit(png: ref Png, raw: ref Rawimage): int
{
if (raw.nchans != 1&& raw.nchans != 3) {
png.error = "only 1 or 3 channels supported";
return 0;
}
# if (png.interlacemethod != 0) {
# png.error = "only progressive supported";
# return 0;
# }
if (png.colortype == 3 && raw.cmap == nil) {
png.error = "PLTE chunk missing";
return 0;
}
png.done = 0;
png.filterbpp = (png.depth * (raw.nchans + png.alpha) + 7) / 8;
png.phase = png.interlacemethod;
processdatainitphase(png, raw);
return 1;
}
upconvert(out: array of byte, outstride: int, in: array of byte, pixels: int, bpp: int)
{
b: byte;
bits := pixels * bpp;
lim := bits / 8;
mask := byte ((1 << bpp) - 1);
outx := 0;
inx := 0;
for (x := 0; x < lim; x++) {
b = in[inx];
for (s := 8 - bpp; s >= 0; s -= bpp) {
pixel := (b >> s) & mask;
ucp := pixel;
for (y := bpp; y < 8; y += bpp)
ucp |= pixel << y;
out[outx] = ucp;
outx += outstride;
}
inx++;
}
residue := (bits % 8) / bpp;
if (residue) {
b = in[inx];
for (s := 8 - bpp; s >= 0; s -= bpp) {
pixel := (b >> s) & mask;
ucp := pixel;
for (y := bpp; y < 8; y += bpp)
ucp |= pixel << y;
out[outx] = ucp;
outx += outstride;
if (--residue <= 0)
break;
}
}
}
# expand (1 or 2 or 4) bit to 8 bit without scaling (for palletized stuff)
expand(out: array of byte, outstride: int, in: array of byte, pixels: int, bpp: int)
{
b: byte;
bits := pixels * bpp;
lim := bits / 8;
mask := byte ((1 << bpp) - 1);
outx := 0;
inx := 0;
for (x := 0; x < lim; x++) {
b = in[inx];
for (s := 8 - bpp; s >= 0; s -= bpp) {
out[outx] = (b >> s) & mask;
outx += outstride;
}
inx++;
}
residue := (bits % 8) / bpp;
if (residue) {
b = in[inx];
for (s := 8 - bpp; s >= 0; s -= bpp) {
out[outx] = (b >> s) & mask;
outx += outstride;
if (--residue <= 0)
break;
}
}
}
copybytes(out: array of byte, outstride: int, in: array of byte, instride: int, pixels: int)
{
inx := 0;
outx := 0;
for (x := 0; x < pixels; x++) {
out[outx] = in[inx];
inx += instride;
outx += outstride;
}
}
outputrow(png: ref Png, raw: ref Rawimage, row: array of byte)
{
offset := png.row * raw.r.max.x;
case raw.nchans {
1 =>
case (png.depth) {
* =>
png.error = "depth not supported";
return;
1 or 2 or 4 =>
if (raw.chandesc == CRGB1)
expand(raw.chans[0][offset + png.colstart:], png.colstep, row, png.phasecols, png.depth);
else
upconvert(raw.chans[0][offset + png.colstart:], png.colstep, row, png.phasecols, png.depth);
8 or 16 =>
# might have an Alpha channel to ignore!
stride := (png.alpha + 1) * png.depth / 8;
copybytes(raw.chans[0][offset + png.colstart:], png.colstep, row, stride, png.phasecols);
}
3 =>
case (png.depth) {
* =>
png.error = "depth not supported (2)";
return;
8 or 16 =>
# split rgb into three channels
bytespc := png.depth / 8;
stride := (3 + png.alpha) * bytespc;
copybytes(raw.chans[0][offset + png.colstart:], png.colstep, row, stride, png.phasecols);
copybytes(raw.chans[1][offset + png.colstart:], png.colstep, row[bytespc:], stride, png.phasecols);
copybytes(raw.chans[2][offset + png.colstart:], png.colstep, row[bytespc * 2:], stride, png.phasecols);
}
}
}
filtersub(png: ref Png)
{
subx := 1;
for (x := int png.filterbpp + 1; x < png.rowsize; x++) {
png.thisrow[x] += png.thisrow[subx];
subx++;
}
}
filterup(png: ref Png)
{
if (png.row == 0)
return;
for (x := 1; x < png.rowsize; x++)
png.thisrow[x] += png.lastrow[x];
}
filteraverage(png: ref Png)
{
for (x := 1; x < png.rowsize; x++) {
a: int;
if (x > png.filterbpp)
a = int png.thisrow[x - png.filterbpp];
else
a = 0;
if (png.row != 0)
a += int png.lastrow[x];
png.thisrow[x] += byte (a / 2);
}
}
filterpaeth(png: ref Png)
{
a, b, c: byte;
p, pa, pb, pc: int;
for (x := 1; x < png.rowsize; x++) {
if (x > png.filterbpp)
a = png.thisrow[x - png.filterbpp];
else
a = byte 0;
if (png.row == 0) {
b = byte 0;
c = byte 0;
} else {
b = png.lastrow[x];
if (x > png.filterbpp)
c = png.lastrow[x - png.filterbpp];
else
c = byte 0;
}
p = int a + int b - int c;
pa = p - int a;
if (pa < 0)
pa = -pa;
pb = p - int b;
if (pb < 0)
pb = -pb;
pc = p - int c;
if (pc < 0)
pc = -pc;
if (pa <= pb && pa <= pc)
png.thisrow[x] += a;
else if (pb <= pc)
png.thisrow[x] += b;
else
png.thisrow[x] += c;
}
}
phaseendcheck(png: ref Png, raw: ref Rawimage): int
{
if (png.row >= raw.r.max.y || png.rowsize <= 1) {
# this phase is over
if (png.phase == 0) {
png.done = 1;
}
else {
png.phase++;
if (png.phase > 7)
png.done = 1;
else
processdatainitphase(png, raw);
}
return 1;
}
return 0;
}
processdata(png: ref Png, raw: ref Rawimage, buf: array of byte)
{
#sys->print("processdata(%d)\n", len buf);
if (png.error != nil)
return;
i := 0;
while (i < len buf) {
if (png.done) {
png.error = "too much data";
return;
}
if (phaseendcheck(png, raw))
continue;
tocopy := (png.rowsize - png.rowbytessofar);
if (tocopy > (len buf - i))
tocopy = len buf - i;
png.thisrow[png.rowbytessofar :] = buf[i : i + tocopy];
i += tocopy;
png.rowbytessofar += tocopy;
if (png.rowbytessofar >= png.rowsize) {
# a new row has arrived
# apply filter here
#sys->print("phase %d row %d\n", png.phase, png.row);
case int png.thisrow[0] {
0 =>
;
1 =>
filtersub(png);
2 =>
filterup(png);
3 =>
filteraverage(png);
4 =>
filterpaeth(png);
* =>
# sys->print("implement filter method %d\n", int png.thisrow[0]);
png.error = "filter method unsupported";
return;
}
# output row
if (png.row >= raw.r.max.y) {
png.error = "too much data";
return;
}
outputrow(png, raw, png.thisrow[1 :]);
png.row += png.rowstep;
save := png.lastrow;
png.lastrow = png.thisrow;
png.thisrow = save;
png.rowbytessofar = 0;
}
}
phaseendcheck(png, raw);
}
png_signature(is: ref ImageSource): int
{
sig := array[8] of { byte 137, byte 80, byte 78, byte 71, byte 13, byte 10, byte 26, byte 10 };
x: int;
for (x = 0; x < 8; x++)
if (png_getb(is) != int sig[x])
return 0;
return 1;
}
png_getb(is: ref ImageSource) : int
{
if(is.i >= len is.bs.data)
return -1;
return int is.bs.data[is.i++];
}
png_bytes(is: ref ImageSource, crc_state: ref CRCstate, buf: array of byte, n: int): int
{
if (is.i +n > len is.bs.data) {
is.i = len is.bs.data;
return 0;
}
if (buf == nil) {
is.i += n;
return 1;
}
buf[0:] = is.bs.data[is.i:is.i+n];
is.i += n;
if (crc_state != nil)
crc->crc(crc_state, buf, n);
return 1;
}
png_skip_bytes(is: ref ImageSource, crc_state: ref CRCstate, n: int): int
{
buf := array[1024] of byte;
while (n) {
thistime: int = 1024;
if (thistime > n)
thistime = n;
if (!png_bytes(is, crc_state, buf, thistime))
return 0;
n -= thistime;
}
return 1;
}
png_get_4(is: ref ImageSource, crc_state: ref CRCstate, signed: int): (int, int)
{
buf := array[4] of byte;
if (!png_bytes(is, crc_state, buf, 4))
return (0, 0);
if (signed && int buf[0] & 16r80)
return (0, 0);
r:int = (int buf[0] << 24) | (int buf[1] << 16) | (int buf[2] << 8) | (int buf[3]);
# sys->print("got int %d\n", r);
return (1, r);
}
png_int(is: ref ImageSource, crc_state: ref CRCstate): int
{
ok, r: int;
(ok, r) = png_get_4(is, crc_state, 1);
if (ok)
return r;
return -1;
}
png_ushort(is: ref ImageSource, crc_state: ref CRCstate): int
{
buf := array[2] of byte;
if (!png_bytes(is, crc_state, buf, 2))
return -1;
return (int buf[0] << 8) | int buf[1];
}
png_crc_and_check(is: ref ImageSource, chunk: ref Chunk): int
{
crc, ok: int;
(ok, crc) = png_get_4(is, nil, 0);
if (!ok)
return 0;
# sys->print("crc: computed %.8ux expected %.8ux\n", chunk.crc_state.crc, crc);
if (chunk.crc_state.crc != crc)
return 1;
return 1;
}
png_byte(is: ref ImageSource, crc_state: ref CRCstate): int
{
buf := array[1] of byte;
if (!png_bytes(is, crc_state, buf, 1))
return -1;
# sys->print("got byte %d\n", int buf[0]);
return int buf[0];
}
png_type(is: ref ImageSource, crc_state: ref CRCstate): string
{
x: int;
buf := array[4] of byte;
if (!png_bytes(is, crc_state, buf, 4))
return nil;
for (x = 0; x < 4; x++) {
c: int;
c = int buf[x];
if ((c < 65 || c > 90 && c < 97) || c > 122)
return nil;
}
return string buf;
}
png_chunk_header(is: ref ImageSource, chunk: ref Chunk): int
{
chunk.size = png_int(is, nil);
if (chunk.size < 0)
return 0;
crc->reset(chunk.crc_state);
chunk.typ = png_type(is, chunk.crc_state);
if (chunk.typ == nil)
return 0;
# sys->print("%s(%d)\n", chunk.typ, chunk.size);
return 1;
}