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Unit infutil;
{ types and macros common to blocks and codes
Copyright (C) 1995-1998 Mark Adler
WARNING: this file should *not* be used by applications. It is
part of the implementation of the compression library and is
subject to change.
Pascal tranlastion
Copyright (C) 1998 by Jacques Nomssi Nzali
For conditions of distribution and use, see copyright notice in readme.txt
}
interface
{$I zconf.inc}
uses
zutil, zbase;
{ copy as much as possible from the sliding window to the output area }
function inflate_flush(var s : inflate_blocks_state;
var z : z_stream;
r : int) : int;
{ And'ing with mask[n] masks the lower n bits }
const
inflate_mask : array[0..17-1] of uInt = (
$0000,
$0001, $0003, $0007, $000f, $001f, $003f, $007f, $00ff,
$01ff, $03ff, $07ff, $0fff, $1fff, $3fff, $7fff, $ffff);
{procedure GRABBITS(j : int);}
{procedure DUMPBITS(j : int);}
{procedure NEEDBITS(j : int);}
implementation
{ macros for bit input with no checking and for returning unused bytes }
procedure GRABBITS(j : int);
begin
{while (k < j) do
begin
Dec(z^.avail_in);
Inc(z^.total_in);
b := b or (uLong(z^.next_in^) shl k);
Inc(z^.next_in);
Inc(k, 8);
end;}
end;
procedure DUMPBITS(j : int);
begin
{b := b shr j;
Dec(k, j);}
end;
procedure NEEDBITS(j : int);
begin
(*
while (k < j) do
begin
{NEEDBYTE;}
if (n <> 0) then
r :=Z_OK
else
begin
{UPDATE}
s.bitb := b;
s.bitk := k;
z.avail_in := n;
Inc(z.total_in, LongInt(p)-LongInt(z.next_in));
z.next_in := p;
s.write := q;
result := inflate_flush(s,z,r);
exit;
end;
Dec(n);
b := b or (uLong(p^) shl k);
Inc(p);
Inc(k, 8);
end;
*)
end;
procedure NEEDOUT;
begin
(*
if (m = 0) then
begin
{WRAP}
if (q = s.zend) and (s.read <> s.window) then
begin
q := s.window;
if LongInt(q) < LongInt(s.read) then
m := uInt(LongInt(s.read)-LongInt(q)-1)
else
m := uInt(LongInt(s.zend)-LongInt(q));
end;
if (m = 0) then
begin
{FLUSH}
s.write := q;
r := inflate_flush(s,z,r);
q := s.write;
if LongInt(q) < LongInt(s.read) then
m := uInt(LongInt(s.read)-LongInt(q)-1)
else
m := uInt(LongInt(s.zend)-LongInt(q));
{WRAP}
if (q = s.zend) and (s.read <> s.window) then
begin
q := s.window;
if LongInt(q) < LongInt(s.read) then
m := uInt(LongInt(s.read)-LongInt(q)-1)
else
m := uInt(LongInt(s.zend)-LongInt(q));
end;
if (m = 0) then
begin
{UPDATE}
s.bitb := b;
s.bitk := k;
z.avail_in := n;
Inc(z.total_in, LongInt(p)-LongInt(z.next_in));
z.next_in := p;
s.write := q;
result := inflate_flush(s,z,r);
exit;
end;
end;
end;
r := Z_OK;
*)
end;
{ copy as much as possible from the sliding window to the output area }
function inflate_flush(var s : inflate_blocks_state;
var z : z_stream;
r : int) : int;
var
n : uInt;
p : pBytef;
q : pBytef;
begin
{ local copies of source and destination pointers }
p := z.next_out;
q := s.read;
{ compute number of bytes to copy as far as end of window }
if ptr2int(q) <= ptr2int(s.write) then
n := uInt(ptr2int(s.write) - ptr2int(q))
else
n := uInt(ptr2int(s.zend) - ptr2int(q));
if (n > z.avail_out) then
n := z.avail_out;
if (n <> 0) and (r = Z_BUF_ERROR) then
r := Z_OK;
{ update counters }
Dec(z.avail_out, n);
Inc(z.total_out, n);
{ update check information }
if Assigned(s.checkfn) then
begin
s.check := s.checkfn(s.check, q, n);
z.adler := s.check;
end;
{ copy as far as end of window }
zmemcpy(p, q, n);
Inc(p, n);
Inc(q, n);
{ see if more to copy at beginning of window }
if (q = s.zend) then
begin
{ wrap pointers }
q := s.window;
if (s.write = s.zend) then
s.write := s.window;
{ compute bytes to copy }
n := uInt(ptr2int(s.write) - ptr2int(q));
if (n > z.avail_out) then
n := z.avail_out;
if (n <> 0) and (r = Z_BUF_ERROR) then
r := Z_OK;
{ update counters }
Dec( z.avail_out, n);
Inc( z.total_out, n);
{ update check information }
if Assigned(s.checkfn) then
begin
s.check := s.checkfn(s.check, q, n);
z.adler := s.check;
end;
{ copy }
zmemcpy(p, q, n);
Inc(p, n);
Inc(q, n);
end;
{ update pointers }
z.next_out := p;
s.read := q;
{ done }
inflate_flush := r;
end;
end.
|
