97 lines
1.9 KiB
C
97 lines
1.9 KiB
C
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#include <u.h>
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#include <libc.h>
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#include <draw.h>
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#include <memdraw.h>
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Memimage*
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creadmemimage(int fd)
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{
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char hdr[5*12+1];
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Rectangle r;
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int m, nb, miny, maxy, new, ldepth, ncblock;
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uchar *buf;
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Memimage *i;
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ulong chan;
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if(readn(fd, hdr, 5*12) != 5*12){
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werrstr("readmemimage: short header (2)");
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return nil;
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}
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/*
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* distinguish new channel descriptor from old ldepth.
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* channel descriptors have letters as well as numbers,
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* while ldepths are a single digit formatted as %-11d.
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*/
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new = 0;
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for(m=0; m<10; m++){
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if(hdr[m] != ' '){
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new = 1;
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break;
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}
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}
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if(hdr[11] != ' '){
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werrstr("creadimage: bad format");
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return nil;
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}
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if(new){
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hdr[11] = '\0';
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if((chan = strtochan(hdr)) == 0){
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werrstr("creadimage: bad channel string %s", hdr);
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return nil;
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}
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}else{
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ldepth = ((int)hdr[10])-'0';
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if(ldepth<0 || ldepth>3){
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werrstr("creadimage: bad ldepth %d", ldepth);
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return nil;
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}
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chan = drawld2chan[ldepth];
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}
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r.min.x=atoi(hdr+1*12);
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r.min.y=atoi(hdr+2*12);
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r.max.x=atoi(hdr+3*12);
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r.max.y=atoi(hdr+4*12);
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if(r.min.x>r.max.x || r.min.y>r.max.y){
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werrstr("creadimage: bad rectangle");
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return nil;
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}
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i = allocmemimage(r, chan);
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if(i == nil)
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return nil;
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ncblock = _compblocksize(r, i->depth);
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buf = malloc(ncblock);
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if(buf == nil)
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goto Errout;
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miny = r.min.y;
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while(miny != r.max.y){
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if(readn(fd, hdr, 2*12) != 2*12){
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Shortread:
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werrstr("readmemimage: short read");
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Errout:
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freememimage(i);
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free(buf);
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return nil;
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}
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maxy = atoi(hdr+0*12);
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nb = atoi(hdr+1*12);
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if(maxy<=miny || r.max.y<maxy){
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werrstr("readimage: bad maxy %d", maxy);
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goto Errout;
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}
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if(nb<=0 || ncblock<nb){
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werrstr("readimage: bad count %d", nb);
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goto Errout;
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}
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if(readn(fd, buf, nb)!=nb)
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goto Shortread;
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if(!new) /* old image: flip the data bits */
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_twiddlecompressed(buf, nb);
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cloadmemimage(i, Rect(r.min.x, miny, r.max.x, maxy), buf, nb);
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miny = maxy;
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}
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free(buf);
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return i;
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}
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