ref: d67596f1bbdce63cd6a053cc17443fde1631ed10
dir: /sys/src/cmd/postscript/g3p9bit/g3p9bit.c/
#include <u.h>
#include <libc.h>
enum
{
ERR,
EOL,
MAKE,
TERM,
};
enum
{
White,
Black,
};
typedef struct Tab
{
ushort run;
ushort bits;
int code;
} Tab;
Tab wtab[8192];
Tab btab[8192];
uchar bitrev[256];
uchar bitnonrev[256];
int readrow(uchar *rev, int*);
void initwbtab(void);
void sync(uchar*);
int readfile(int, char*, char*);
int nbytes;
uchar *bytes;
uchar *pixels;
uchar *buf;
int y;
uint bitoffset;
uint word24;
enum
{
Bytes = 1024*1024,
Lines = 1410, /* 1100 for A4, 1410 for B4 */
Dots = 1728,
};
void
error(char *fmt, ...)
{
char buf[256];
va_list arg;
if(fmt){
va_start(arg, fmt);
vseprint(buf, buf+sizeof buf, fmt, arg);
va_end(arg);
fprint(2, "g3: %s\n", buf);
}
exits(fmt);
}
void
usage(void)
{
fprint(2, "usage: g3p9bit [-gy] file\n");
exits("usage");
}
void
main(int argc, char **argv)
{
int y, fd, n, m;
char *t;
char *file, err[ERRMAX], tbuf[5*12+1];
int gray=0;
int yscale=1;
ARGBEGIN{
case 'g':
/* do simulated 2bit gray to compress x */
gray++;
break;
case 'y':
/* double each scan line to double the y resolution */
yscale=2;
break;
default:
usage();
}ARGEND
if(argc > 1)
usage();
initwbtab();
buf = malloc(1024*1024);
t = malloc((Dots/8)*Lines);
if(buf==nil || t==nil)
error("malloc failed: %r\n");
pixels = (uchar*)t;
file = "<stdin>";
fd = 0;
if(argc > 0){
file = argv[0];
fd = open(file, OREAD);
if(fd < 0)
error("can't open %s", file);
}
y = readfile(fd, file, err);
if(y < 0)
error(err);
sprint(tbuf, "%11d %11d %11d %11d %11d ", gray, 0, 0, Dots/(gray+1), y*yscale);
write(1, tbuf, 5*12);
n = (Dots/8)*y*yscale;
/* write in pieces; brazil pipes work badly with huge counts */
while(n > 0){
if(yscale > 1) /* write one scan line */
m = Dots/8;
else{ /* write lots */
m = n;
if(m > 8192)
m = 8192;
}
for(y=0; y<yscale; y++){
if(write(1, t, m) != m)
error("write error");
n -= m;
}
t += m;
}
if(err[0])
error(err);
error(nil);
}
enum{
Hvres,
Hbaud,
Hwidth,
Hlength,
Hcomp,
HenabECM,
HenabBFT,
Hmsperscan,
};
int defhdr[8] = {
0, /* 98 lpi */
0, /* 2400 baud */
0, /* 1728 pixels in 215mm */
0, /* A4, 297mm */
0, /* 1-D modified huffman */
0, /* disable ECM */
0, /* disable BFT */
3, /* 10 ms per scan */
};
int
crackhdr(uchar *ap, int *hdr)
{
char *p, *q;
int i;
p = (char*)ap;
q = p;
for(i=0; i<8; i++){
if(*p<'0' || '9'<*p)
return -1;
hdr[i] = strtol(p, &q, 0);
p = q+1;
}
return p-(char*)ap;
}
int
readfile(int f, char *file, char *err)
{
int i, r, lines;
uchar *rev;
int hdr[8];
err[0] = 0;
memset(pixels, 0, (Dots/8) * Lines);
nbytes = readn(f, buf, 1024*1024);
if(nbytes==1024*1024 || nbytes<=100){
bad:
sprint(err, "g3: file improper size or format: %s", file);
return -1;
}
bytes = buf;
if(bytes[0]=='I' && bytes[1]=='I' && bytes[2]=='*'){ /* dumb PC format */
bytes += 0xf3;
nbytes -= 0xf3;
rev = bitrev;
memmove(hdr, defhdr, sizeof defhdr);
}else if(bytes[0] == 0 && strcmp((char*)bytes+1, "PC Research, Inc") == 0){ /* digifax format */
memmove(hdr, defhdr, sizeof defhdr);
if(bytes[45] == 0x40 && bytes[29] == 1) /* high resolution */
hdr[Hvres] = 1;
else
hdr[Hvres] = 0;
/* hdr[26] | (hdr[27]<<8) is page number */
bytes += 64;
nbytes -= 64;
rev = bitnonrev;
}else{
while(nbytes > 2){
if(bytes[0]=='\n'){
if(strncmp((char*)bytes+1, "FDCS=", 5) == 0){
i = crackhdr(bytes+6, hdr);
if(i < 0){
sprint(err, "g3: bad FDCS in header: %s", file);
return -1;
}
if(hdr[Hwidth] != 0){
sprint(err, "g3: unsupported width: %s", file);
return -1;
}
if(hdr[Hcomp] != 0){
sprint(err, "g3: unsupported compression: %s", file);
return -1;
}
bytes += i+1;
nbytes -= i+1;
continue;
}
if(bytes[1] == '\n'){
bytes += 2;
nbytes -= 2;
break;
}
}
bytes++;
nbytes--;
}
if(nbytes < 2)
goto bad;
rev = bitnonrev;
}
bitoffset = 24;
word24 = 0;
sync(rev);
lines = Lines;
if(hdr[Hvres] == 1)
lines *= 2;
for(y=0; y<lines; y++){
r = readrow(rev, hdr);
if(r < 0)
break;
if(r == 0)
sync(rev);
}
if(hdr[Hvres] == 1)
y /= 2;
// if(y < 100)
// goto bad;
return y;
}
int
readrow(uchar *rev, int *hdr)
{
int bo, state;
Tab *tab, *t;
int x, oldx, x2, oldx2, dx, xx;
uint w24;
uchar *p, *q;
state = White;
oldx = 0;
bo = bitoffset;
w24 = word24;
x = y;
if(hdr[Hvres] == 1) /* high resolution */
x /= 2;
p = pixels + x*Dots/8;
x = 0;
loop:
if(x > Dots)
return 0;
if(state == White)
tab = wtab;
else
tab = btab;
if(bo > (24-13)) {
do {
if(nbytes <= 0)
return -1;
w24 = (w24<<8) | rev[*bytes];
bo -= 8;
bytes++;
nbytes--;
} while(bo >= 8);
}
t = tab + ((w24 >> (24-13-bo)) & 8191);
x += t->run;
bo += t->bits;
if(t->code == TERM){
if(state == White)
oldx = x;
else{
oldx2 = oldx;
x2 = x;
xx = oldx2&7;
q = p+oldx2/8;
if(x2/8 == oldx2/8) /* all in one byte, but if((x2&7)==0), do harder case */
*q |= (0xFF>>xx) & (0xFF<<(8-(x2&7)));
else{
dx = x2 - oldx2;
/* leading edge */
if(xx){
*q++ |= 0xFF>>xx;
dx -= 8-xx;
}
/* middle */
while(dx >= 8){
*q++ = 0xFF;
dx -= 8;
}
/* trailing edge */
if(dx)
*q |= 0xFF<<(8-dx);
}
}
state ^= White^Black;
goto loop;
}
if(t->code == ERR){
bitoffset = bo;
word24 = w24;
return 0;
}
if(t->code == EOL){
bitoffset = bo;
word24 = w24;
return 1;
}
goto loop;
}
void
sync(uchar *rev)
{
Tab *t;
int c;
c = 0;
loop:
if(bitoffset > (24-13)) {
do {
if(nbytes <= 0)
return;
word24 = (word24<<8) | rev[*bytes];
bitoffset -= 8;
bytes++;
nbytes--;
} while(bitoffset >= 8);
}
t = wtab + ((word24 >> (24-13-bitoffset)) & 8191);
if(t->code != EOL) {
bitoffset++;
c++;
goto loop;
}
bitoffset += t->bits;
}
typedef struct File
{
char *val;
int code;
}File;
File ibtab[] = {
#include "btab"
{nil, 0}
};
File iwtab[] = {
#include "wtab"
{nil, 0}
};
int
binary(char *s)
{
int n;
n = 0;
while(*s)
n = n*2 + *s++-'0';
return n;
}
void
tabinit(File *file, Tab *tab)
{
int i, j, v, r, l;
char *b;
for(v=0; v<8192; v++) {
tab[v].run = 0;
tab[v].bits = 1;
tab[v].code = ERR;
}
for(i=0; b=file[i].val; i++){
l = strlen(b);
v = binary(b);
r = file[i].code;
if(l > 13)
fprint(2, "g3: oops1 l = %d %s\n", l, b);
v = v<<(13-l);
for(j=0; j<(1<<((13-l))); j++) {
if(tab[v].code != ERR)
fprint(2, "g3: oops2 %d %s\n", r, b);
tab[v].run = r;
tab[v].bits = l;
tab[v].code = TERM;
if(r < 0) {
tab[v].run = 0;
tab[v].code = EOL;
if(r < -1) {
tab[v].bits = 1;
tab[v].code = MAKE;
}
}
if(r >= 64) {
tab[v].code = MAKE;
}
v++;
}
}
for(i=0; i<256; i++)
for(j=0; j<8; j++)
if(i & (1<<j))
bitrev[i] |= 0x80 >> j;
for(i=0; i<256; i++)
bitnonrev[i] = i;
}
void
initwbtab(void)
{
tabinit(iwtab, wtab);
tabinit(ibtab, btab);
}