Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>

int
loadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
{
        int y, l, lpart, rpart, mx, m, mr;
        uchar *q;

        if(!rectinrect(r, i->r))
                return -1;
        l = bytesperline(r, i->depth);
        if(ndata < l*Dy(r))
                return -1;
        ndata = l*Dy(r);
        q = byteaddr(i, r.min);
        mx = 7/i->depth;
        lpart = (r.min.x & mx) * i->depth;
        rpart = (r.max.x & mx) * i->depth;
        m = 0xFF >> lpart;
        /* may need to do bit insertion on edges */
        if(l == 1){     /* all in one byte */
                if(rpart)
                        m ^= 0xFF >> rpart;
                for(y=r.min.y; y<r.max.y; y++){
                        *q ^= (*data^*q) & m;
                        q += i->width*sizeof(ulong);
                        data++;
                }
                return ndata;
        }
        if(lpart==0 && rpart==0){       /* easy case */
                for(y=r.min.y; y<r.max.y; y++){
                        memmove(q, data, l);
                        q += i->width*sizeof(ulong);
                        data += l;
                }
                return ndata;
        }
        mr = 0xFF ^ (0xFF >> rpart);
        if(lpart!=0 && rpart==0){
                for(y=r.min.y; y<r.max.y; y++){
                        *q ^= (*data^*q) & m;
                        if(l > 1)
                                memmove(q+1, data+1, l-1);
                        q += i->width*sizeof(ulong);
                        data += l;
                }
                return ndata;
        }
        if(lpart==0 && rpart!=0){
                for(y=r.min.y; y<r.max.y; y++){
                        if(l > 1)
                                memmove(q, data, l-1);
                        q[l-1] ^= (data[l-1]^q[l-1]) & mr;
                        q += i->width*sizeof(ulong);
                        data += l;
                }
                return ndata;
        }
        for(y=r.min.y; y<r.max.y; y++){
                *q ^= (*data^*q) & m;
                if(l > 2)
                        memmove(q+1, data+1, l-2);
                q[l-1] ^= (data[l-1]^q[l-1]) & mr;
                q += i->width*sizeof(ulong);
                data += l;
        }
        return ndata;
}