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/*
* Unpacks the raster data from the packed buffer. This code was
* translated from pktopx.web using an automatic translator, then
* converted for this purpose. This little routine can be very useful
* in other drivers as well.
*/
#include "dvips.h" /* The copyright notice in that file is included too! */
/*
* The external declarations:
*/
#include "protos.h"
/*
* Some statics for use here.
*/
static halfword bitweight;
static halfword dynf;
static halfword gpower[17] = { 0 , 1 , 3 , 7 , 15 , 31 , 63 , 127 ,
255 , 511 , 1023 , 2047 , 4095 , 8191 , 16383 , 32767 , 65535 };
static long repeatcount;
static quarterword *p;
/*
* We need procedures to get a nybble, bit, and packed word from the
* packed data structure.
*/
static shalfword
getnyb(void)
{
if ( bitweight == 0 )
{ bitweight = 16;
return(*p++ & 15);
} else {
bitweight = 0;
return(*p >> 4);
}
}
static Boolean
getbit(void)
{
bitweight >>= 1;
if ( bitweight == 0 )
{ p++;
bitweight = 128;
}
return(*p & bitweight);
}
static long
pkpackednum(void) {
register halfword i;
register long j;
i = getnyb ();
if ( i == 0 ) {
do { j = getnyb ();
i++;
} while ( j == 0 );
while ( i != 0 ) {
j = j * 16 + ((long) getnyb ());
i--;
}
return ( j - 15 + ( 13 - dynf ) * 16 + dynf );
}
else if ( i <= dynf ) return ( i );
else if ( i < 14 ) return ( ( i - dynf - 1 )*16 + getnyb() + dynf + 1 );
else {
if (repeatcount != 0)
error("! recursive repeat count in pk file");
repeatcount = 1;
if ( i == 14 ) repeatcount = pkpackednum ();
return ( pkpackednum() );
}
}
static void
flip(register char *s, register long howmany)
{
register char t;
while (howmany > 0) {
t = *s;
*s = s[1];
s[1] = t;
howmany--;
s += 2;
}
}
/*
* And now we have our main routine.
*/
static halfword bftest = 1;
long
unpack(quarterword *pack, halfword *raster,
halfword cwidth, halfword cheight, halfword cmd)
{
register integer i, j;
shalfword wordwidth;
register halfword word, wordweight;
shalfword rowsleft;
Boolean turnon;
shalfword hbit, ww;
long count;
halfword *oraster;
oraster = raster;
p = pack;
dynf = cmd / 16;
turnon = cmd & 8;
wordwidth = (cwidth + 15)/16;
if ( dynf == 14 )
{ bitweight = 256;
for ( i = 1; i <= cheight; i ++ )
{ word = 0;
wordweight = 32768;
for ( j = 1; j <= cwidth; j ++ )
{ if ( getbit () ) word += wordweight;
wordweight >>= 1;
if ( wordweight == 0 )
{ *raster++ = word;
word = 0;
wordweight = 32768;
}
}
if ( wordweight != 32768 )
*raster++ = word;
}
} else {
rowsleft = cheight;
hbit = cwidth;
repeatcount = 0;
ww = 16;
word = 0;
bitweight = 16;
while ( rowsleft > 0 )
{ count = pkpackednum();
while ( count != 0 )
{ if ( ( count <= ww ) && ( count < hbit ) )
{ if ( turnon ) word += gpower [ ww ] - gpower
[ ww - count ];
hbit -= count;
ww -= count;
count = 0;
}
else if ( ( count >= hbit ) && ( hbit <= ww ) )
{ if ( turnon )
word += gpower[ww] - gpower[ww-hbit];
*raster++ = word;
for ( i = 1; i <= repeatcount; i ++ ) {
for ( j = 1; j <= wordwidth; j ++ ) {
*raster = *(raster - wordwidth);
raster++;
}
}
rowsleft -= repeatcount + 1;
repeatcount = 0;
word = 0;
ww = 16;
count -= hbit;
hbit = cwidth;
}
else
{ if ( turnon ) word += gpower [ ww ];
*raster++ = word;
word = 0;
count -= ww;
hbit -= ww;
ww = 16;
}
}
turnon = ! turnon;
}
if ( ( rowsleft != 0 ) || ( (unsigned)hbit != cwidth ) )
error ( "! error while unpacking; more bits than required" );
}
if (*(char *)&bftest) /* is the hardware LittleEndian? */
flip((char *)oraster, ((cwidth + 15) >> 4) * (long)cheight);
return(p-pack);
}
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