123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111 |
- #include <u.h>
- #include <libc.h>
- #include <draw.h>
- #include <memdraw.h>
- Memimage*
- readmemimage(int fd)
- {
- char hdr[5*12+1];
- int dy;
- ulong chan;
- uint l, n;
- int m, j;
- int new, miny, maxy;
- Rectangle r;
- uchar *tmp;
- int ldepth, chunk;
- Memimage *i;
- if(readn(fd, hdr, 11) != 11){
- werrstr("readimage: short header");
- return nil;
- }
- if(memcmp(hdr, "compressed\n", 11) == 0)
- return creadmemimage(fd);
- if(readn(fd, hdr+11, 5*12-11) != 5*12-11){
- werrstr("readimage: 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("readimage: bad format");
- return nil;
- }
- if(new){
- hdr[11] = '\0';
- if((chan = strtochan(hdr)) == 0){
- werrstr("readimage: bad channel string %s", hdr);
- return nil;
- }
- }else{
- ldepth = ((int)hdr[10])-'0';
- if(ldepth<0 || ldepth>3){
- werrstr("readimage: 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("readimage: bad rectangle");
- return nil;
- }
- miny = r.min.y;
- maxy = r.max.y;
- l = bytesperline(r, chantodepth(chan));
- i = allocmemimage(r, chan);
- if(i == nil)
- return nil;
- chunk = 32*1024;
- if(chunk < l)
- chunk = l;
- tmp = malloc(chunk);
- if(tmp == nil)
- goto Err;
- while(maxy > miny){
- dy = maxy - miny;
- if(dy*l > chunk)
- dy = chunk/l;
- if(dy <= 0){
- werrstr("readmemimage: image too wide for buffer");
- goto Err;
- }
- n = dy*l;
- m = readn(fd, tmp, n);
- if(m != n){
- werrstr("readmemimage: read count %d not %d: %r", m, n);
- Err:
- freememimage(i);
- free(tmp);
- return nil;
- }
- if(!new) /* an old image: must flip all the bits */
- for(j=0; j<chunk; j++)
- tmp[j] ^= 0xFF;
- if(loadmemimage(i, Rect(r.min.x, miny, r.max.x, miny+dy), tmp, chunk) <= 0)
- goto Err;
- miny += dy;
- }
- free(tmp);
- return i;
- }
|