ref: 7af5442d3b031a3f81ea5c25c88f99692fb16822
dir: /sys/src/libmemdraw/cload.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(badrect(r) || !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; }