sys/src/libmemdraw/cload.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <draw.h>
   4 #include <memdraw.h>
   5
   6 int
   7 cloadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
   8 {
   9         int y, bpl, c, cnt, offs;
  10         uchar mem[NMEM], *memp, *omemp, *emem, *linep, *elinep, *u, *eu;
  11
  12         if(badrect(r) || !rectinrect(r, i->r))
  13                 return -1;
  14         bpl = bytesperline(r, i->depth);
  15         u = data;
  16         eu = data+ndata;
  17         memp = mem;
  18         emem = mem+NMEM;
  19         y = r.min.y;
  20         linep = byteaddr(i, Pt(r.min.x, y));
  21         elinep = linep+bpl;
  22         for(;;){
  23                 if(linep == elinep){
  24                         if(++y == r.max.y)
  25                                 break;
  26                         linep = byteaddr(i, Pt(r.min.x, y));
  27                         elinep = linep+bpl;
  28                 }
  29                 if(u == eu){    /* buffer too small */
  30                         return -1;
  31                 }
  32                 c = *u++;
  33                 if(c >= 128){
  34                         for(cnt=c-128+1; cnt!=0 ;--cnt){
  35                                 if(u == eu){            /* buffer too small */
  36                                         return -1;
  37                                 }
  38                                 if(linep == elinep){    /* phase error */
  39                                         return -1;
  40                                 }
  41                                 *linep++ = *u;
  42                                 *memp++ = *u++;
  43                                 if(memp == emem)
  44                                         memp = mem;
  45                         }
  46                 }
  47                 else{
  48                         if(u == eu)     /* short buffer */
  49                                 return -1;
  50                         offs = *u++ + ((c&3)<<8)+1;
  51                         if(memp-mem < offs)
  52                                 omemp = memp+(NMEM-offs);
  53                         else
  54                                 omemp = memp-offs;
  55                         for(cnt=(c>>2)+NMATCH; cnt!=0; --cnt){
  56                                 if(linep == elinep)     /* phase error */
  57                                         return -1;
  58                                 *linep++ = *omemp;
  59                                 *memp++ = *omemp++;
  60                                 if(omemp == emem)
  61                                         omemp = mem;
  62                                 if(memp == emem)
  63                                         memp = mem;
  64                         }
  65                 }
  66         }
  67         return u-data;
  68 }