tbbits.c - plan9port - [fork] Plan 9 from user space
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       ---
       tbbits.c (2101B)
       ---
            1 #include        <u.h>
            2 #include        <libc.h>
            3 #include        <libg.h>
            4 #include        <bio.h>
            5 #include        "hdr.h"
            6 
            7 enum {
            8         Charsperfont        = 157,
            9         Void1b                = (0xC6-0xA2)*Charsperfont+0x3f,
           10         Void1e                = (0xC9-0xA2)*Charsperfont - 1
           11 };
           12 
           13 Bitmap *
           14 breadbits(char *file, int n, long *chars, int size, uchar *bits, int **doneptr)
           15 {
           16         Bitmap *bm;
           17         Biobuf *bf;
           18         int i, j, byt;
           19         int nch;
           20         long c;
           21         uchar *b, *nbits;
           22         int *done;
           23         static uchar missing[32] = {0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x08, 0x00, 0x04, 0x00, 0x02, 0x00, 0x01, 0x00, 0x00, 0x80, 0x00, 0x40, 0x00, 0x20, 0x00, 0x10, 0x00, 0x08, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
           24         uchar buf[32];
           25 
           26         bf = Bopen(file, OREAD);
           27         if(bf == 0){
           28                 fprint(2, "%s: %s: %r\n", argv0, file);
           29                 exits("bitfile open error");
           30         }
           31         done = (int *)malloc(n*sizeof(done[0]));
           32         if(done == 0){
           33                 fprint(2, "%s: malloc error (%d bytes)\n", argv0, n);
           34                 exits("malloc error");
           35         }
           36         *doneptr = done;
           37         byt = size/8;
           38         nch = 0;
           39         for(i = 0; i < n; i++){
           40                 done[i] = 1;
           41                 nch++;
           42                 c = chars[i];
           43                 if((c >= Void1b) && (c <= Void1e)){
           44                         done[i] = 0;
           45                         nch--;
           46                         continue;
           47                 }
           48                 /* magic via presotto for calculating the seek */
           49                 j = c;
           50                 if(c >= 2*Charsperfont)
           51                         j += 294;        /* baffling hole between A3 and A4 */
           52                 if(c > Void1e)
           53                         j -= 3*Charsperfont - 0x3F;
           54                 j *= byt*size;                /* bytes per char */
           55                 j += 256;                /* 256 front matter */
           56                 Bseek(bf, j, 0);
           57                 Bread(bf, buf, sizeof(missing));
           58                 if(memcmp(buf, missing, sizeof(missing)) == 0){
           59                         done[i] = 0;
           60                         nch--;
           61                         continue;
           62                 }
           63                 Bseek(bf, j, 0);
           64                 b = bits + i*byt;
           65                 for(j = 0; j < size; j++){        /* rows */
           66                         Bread(bf, b, byt);
           67                         b += n*byt;
           68                 }
           69         }
           70         nbits = (uchar *)malloc(nch*byt*size);
           71         if(nbits == 0){
           72                 fprint(2, "%s: malloc error (%d bytes)\n", argv0, nch*byt);
           73                 exits("malloc error");
           74         }
           75         c = 0;
           76         for(i = 0; i < n; i++)
           77                 if(done[i]){
           78                         for(j = 0; j < size; j++)
           79                                 memmove(nbits+c*byt+j*nch*byt, bits+i*byt+j*n*byt, byt);
           80                         c++;
           81                 }
           82         bm = balloc((Rectangle){(Point){0, 0}, (Point){nch*size, size}}, 0);
           83         if(bm == 0){
           84                 fprint(2, "%s: balloc failure\n", argv0);
           85                 exits("balloc failure");
           86         }
           87         wrbitmap(bm, 0, size, nbits);
           88         return(bm);
           89 }