drawterm/libmemdraw/cload.c

69 lines
1.3 KiB
C

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>
int
_cloadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
{
int y, bpl, c, cnt, offs;
uchar mem[NMEM], *memp, *omemp, *emem, *linep, *elinep, *u, *eu;
if(!rectinrect(r, i->r))
return -1;
bpl = bytesperline(r, i->depth);
u = data;
eu = data+ndata;
memp = mem;
emem = mem+NMEM;
y = r.min.y;
linep = byteaddr(i, Pt(r.min.x, y));
elinep = linep+bpl;
for(;;){
if(linep == elinep){
if(++y == r.max.y)
break;
linep = byteaddr(i, Pt(r.min.x, y));
elinep = linep+bpl;
}
if(u == eu){ /* buffer too small */
return -1;
}
c = *u++;
if(c >= 128){
for(cnt=c-128+1; cnt!=0 ;--cnt){
if(u == eu){ /* buffer too small */
return -1;
}
if(linep == elinep){ /* phase error */
return -1;
}
*linep++ = *u;
*memp++ = *u++;
if(memp == emem)
memp = mem;
}
}
else{
if(u == eu) /* short buffer */
return -1;
offs = *u++ + ((c&3)<<8)+1;
if(memp-mem < offs)
omemp = memp+(NMEM-offs);
else
omemp = memp-offs;
for(cnt=(c>>2)+NMATCH; cnt!=0; --cnt){
if(linep == elinep) /* phase error */
return -1;
*linep++ = *omemp;
*memp++ = *omemp++;
if(omemp == emem)
omemp = mem;
if(memp == emem)
memp = mem;
}
}
}
return u-data;
}