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