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* Fix compression bug.

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+ Allow random seeks through compressed file.

git-svn-id: trunk@9362 -
This commit is contained in:
daniel 2007-12-01 10:13:42 +00:00
parent 1380a64b1e
commit 0d744e656b
1 changed files with 41 additions and 10 deletions
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51
packages/paszlib/src/zstream.pp
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@ -68,6 +68,8 @@ type
Tdecompressionstream=class(Tcustomzlibstream)
protected
raw_read,compressed_read:longint;
skipheader:boolean;
procedure reset;
public
constructor create(Asource:Tstream;Askipheader:boolean=false);
destructor destroy;override;
@ -173,6 +175,7 @@ function Tcompressionstream.write(const buffer;count:longint):longint;
var err:smallint;
lastavail,
written:longint;
begin
Fstream.next_in:=@buffer;
Fstream.avail_in:=count;
@ -207,8 +210,10 @@ end;
procedure Tcompressionstream.flush;
var err:smallint;
written:longint;
begin
{Compress remaining data still in internal zlib data buffers.}
repeat
@ -230,8 +235,8 @@ begin
until false;
if Fstream.avail_out<bufsize then
begin
source.writebuffer(FBuffer,bufsize-Fstream.avail_out);
inc(compressed_written,written);
source.writebuffer(FBuffer^,bufsize-Fstream.avail_out);
inc(compressed_written,bufsize-Fstream.avail_out);
progress(self);
end;
end;
@ -257,6 +262,7 @@ var err:smallint;
begin
inherited create(Asource);
skipheader:=Askipheader;
if Askipheader then
err:=inflateInit2(Fstream,-MAX_WBITS)
else
@ -269,6 +275,7 @@ function Tdecompressionstream.read(var buffer;count:longint):longint;
var err:smallint;
lastavail:longint;
begin
Fstream.next_out:=@buffer;
Fstream.avail_out:=count;
@ -297,21 +304,45 @@ begin
read:=count-Fstream.avail_out;
end;
function Tdecompressionstream.seek(offset:longint;origin:word):longint;
procedure Tdecompressionstream.reset;
var err:smallint;
begin
if ((origin=sofrombeginning) and (offset>=raw_read)) or
((origin=sofromcurrent) and (offset>=0)) then
raw_read:=0;
compressed_read:=0;
source.position:=0;
inflateEnd(Fstream);
if skipheader then
err:=inflateInit2(Fstream,-MAX_WBITS)
else
err:=inflateInit(Fstream);
if err<>Z_OK then
raise Ecompressionerror.create(zerror(err));
end;
function Tdecompressionstream.seek(offset:longint;origin:word):longint;
var c:longint;
begin
if (origin=sofrombeginning) or
((origin=sofromcurrent) and (offset+raw_read>=0)) then
begin
if origin=sofrombeginning then
dec(offset,raw_read);
if offset<0 then
begin
inc(offset,raw_read);
reset;
end;
while offset>0 do
begin
size:=bufsize;
if offset<bufsize then
size:=offset;
size:=read(Fbuffer^,size);
dec(offset,size);
c:=offset;
if c>bufsize then
c:=bufsize;
c:=read(Fbuffer^,c);
dec(offset,c);
end;
end
else