Subversion Repositories planix.SVN

#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;
}