load.c - vx32 - Local 9vx git repository for patches.
 (HTM) git clone git://r-36.net/vx32
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       ---
       load.c (1500B)
       ---
            1 #include "u.h"
            2 #include "lib.h"
            3 #include "draw.h"
            4 #include "memdraw.h"
            5 
            6 int
            7 _loadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
            8 {
            9         int y, l, lpart, rpart, mx, m, mr;
           10         uchar *q;
           11 
           12         if(!rectinrect(r, i->r))
           13                 return -1;
           14         l = bytesperline(r, i->depth);
           15         if(ndata < l*Dy(r))
           16                 return -1;
           17         ndata = l*Dy(r);
           18         q = byteaddr(i, r.min);
           19         mx = 7/i->depth;
           20         lpart = (r.min.x & mx) * i->depth;
           21         rpart = (r.max.x & mx) * i->depth;
           22         m = 0xFF >> lpart;
           23         /* may need to do bit insertion on edges */
           24         if(l == 1){        /* all in one byte */
           25                 if(rpart)
           26                         m ^= 0xFF >> rpart;
           27                 for(y=r.min.y; y<r.max.y; y++){
           28                         *q ^= (*data^*q) & m;
           29                         q += i->width*sizeof(uint32);
           30                         data++;
           31                 }
           32                 return ndata;
           33         }
           34         if(lpart==0 && rpart==0){        /* easy case */
           35                 for(y=r.min.y; y<r.max.y; y++){
           36                         memmove(q, data, l);
           37                         q += i->width*sizeof(uint32);
           38                         data += l;
           39                 }
           40                 return ndata;
           41         }
           42         mr = 0xFF ^ (0xFF >> rpart);
           43         if(lpart!=0 && rpart==0){
           44                 for(y=r.min.y; y<r.max.y; y++){
           45                         *q ^= (*data^*q) & m;
           46                         if(l > 1)
           47                                 memmove(q+1, data+1, l-1);
           48                         q += i->width*sizeof(uint32);
           49                         data += l;
           50                 }
           51                 return ndata;
           52         }
           53         if(lpart==0 && rpart!=0){
           54                 for(y=r.min.y; y<r.max.y; y++){
           55                         if(l > 1)
           56                                 memmove(q, data, l-1);
           57                         q[l-1] ^= (data[l-1]^q[l-1]) & mr;
           58                         q += i->width*sizeof(uint32);
           59                         data += l;
           60                 }
           61                 return ndata;
           62         }
           63         for(y=r.min.y; y<r.max.y; y++){
           64                 *q ^= (*data^*q) & m;
           65                 if(l > 2)
           66                         memmove(q+1, data+1, l-2);
           67                 q[l-1] ^= (data[l-1]^q[l-1]) & mr;
           68                 q += i->width*sizeof(uint32);
           69                 data += l;
           70         }
           71         return ndata;
           72 }