this file reads bdf fonts. it is mapping dependent in that the ENCODING

#include <u.h>
#include <libc.h>
#include <libg.h>
#include <bio.h>
#include "hdr.h"

/*
this file reads bdf fonts. it is mapping dependent in that the ENCODING
field is font dependent.
*/

static char *field(Biobuf *, char *);

Bitmap *
greadbits(char *file, int n, long *chars, int size, uchar *bits, int **doneptr)
{
Bitmap *bm;
Biobuf *bf;
char *p, *s;
long kmin, kmax;
int i, j, byt;
int nch;
long c;
uchar *b;
int *done;
uchar *nbits;
char buf[1024]; /* big enough for one char! */
static int dig[256] = {
['0'] 0, ['1'] 1, ['2'] 2, ['3'] 3, ['4'] 4, ['5'] 5, ['6'] 6, ['7'] 7,
['8'] 8, ['9'] 9, ['a'] 10, ['b'] 11, ['c'] 12, ['d'] 13, ['e'] 14, ['f'] 15,
};

bf = Bopen(file, OREAD);
if(bf == 0){
fprint(2, "%s: %s: %r\n", argv0, file);
exits("bitfile open error");
}
done = (int *)malloc(n*sizeof(done[0]));
if(done == 0){
fprint(2, "%s: malloc error (%d bytes)\n", argv0, n);
exits("malloc error");
}
*doneptr = done;
memset(done, 0, n*sizeof(done[0]));
kmin = 65536;
kmax = 0;
for(i = 0; i < n; i++){
c = chars[i];
if(kmin > c)
kmin = c;
if(kmax < c)
kmax = c;
}
nch = 0;
byt = size/8;
for(;;){
while(s = Brdline(bf, '\n')){
if(strncmp(s, "STARTCHAR", 9) == 0)
break;
}
if(s == 0)
break;
s = field(bf, "ENCODING");
c = strtol(s, (char **)0, 10);
c = (c/256 - 0xA0)*100 + (c%256 - 0xA0);
field(bf, "BITMAP");
p = buf;
for(i = 0; i < size; i++){ /* rows */
if((s = Brdline(bf, '\n')) == 0){
exits("bad bdf");
}
memcpy(p, s, 2*byt);
p += 2*byt;
}
field(bf, "ENDCHAR");
if((c < kmin) || (c > kmax))
continue;
for(i = 0; i < n; i++)
if(c == chars[i]){
nch++;
done[i] = 1;
p = buf;
b = bits + i*byt;
for(i = 0; i < size; i++){ /* rows */
for(j = 0; j < byt; j++){
*b++ = (dig[*p]<<4) | dig[p[1]];
p += 2;
}
b += (n-1)*byt;
}
break;
}
}
nbits = (uchar *)malloc(nch*byt*size);
if(nbits == 0){
fprint(2, "%s: malloc error (%d bytes)\n", argv0, nch*byt);
exits("malloc error");
}
c = 0;
for(i = 0; i < n; i++)
if(done[i]){
for(j = 0; j < size; j++)
memmove(nbits+c*byt+j*nch*byt, bits+i*byt+j*n*byt, byt);
c++;
}
bm = balloc((Rectangle){(Point){0, 0}, (Point){nch*size, size}}, 0);
if(bm == 0){
fprint(2, "%s: balloc failure\n", argv0);
exits("balloc failure");
}
wrbitmap(bm, 0, size, nbits);
for(i = 0; i < n; i++)
if(done[i] == 0){
/*fprint(2, "char 0x%x (%d) not found\n", chars[i], chars[i]);/**/
}
return(bm);
}

static char *
field(Biobuf *bf, char *name)
{
char *s;
int n;

n = strlen(name);
while(s = Brdline(bf, '\n')){
if(strncmp(s, name, n) == 0)
return(s+n);
if(strncmp(s, "ENDCHAR", 7) == 0){
fprint(2, "%s: char missing %s field\n", argv0, name);
exits("bad bdf");
}
}
fprint(2, "%s: char missing %s field; unexpected EOF\n", argv0, name);
exits("bad bdf");
return(0);
}