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//========================================================================
//
// FlateEncoder.cc
//
// Copyright (C) 2016, William Bader <williambader@hotmail.com>
// Copyright (C) 2017 Adrian Johnson <ajohnson@redneon.com>
// Copyright (C) 2021 Even Rouault <even.rouault@spatialys.com>
// Copyright (C) 2022 Albert Astals Cid <aacid@kde.org>
//
// This file is under the GPLv2 or later license
//
//========================================================================
#include <config.h>
#include "FlateEncoder.h"
//------------------------------------------------------------------------
// FlateEncoder
//------------------------------------------------------------------------
FlateEncoder::FlateEncoder(Stream *strA) : FilterStream(strA)
{
int zlib_status;
outBufPtr = outBufEnd = outBuf;
inBufEof = outBufEof = false;
// We used to assign Z_NULL to the 3 following members of zlib_stream,
// but as Z_NULL is a #define to 0, using it triggers the
// -Wzero-as-null-pointer-constant warning.
// For safety, check that the Z_NULL definition is equivalent to
// 0 / null pointer.
static_assert(static_cast<int>(Z_NULL) == 0);
zlib_stream.zalloc = nullptr;
zlib_stream.zfree = nullptr;
zlib_stream.opaque = nullptr;
zlib_status = deflateInit(&zlib_stream, Z_DEFAULT_COMPRESSION);
if (zlib_status != Z_OK) {
inBufEof = outBufEof = true;
error(errInternal, -1, "Internal: deflateInit() failed in FlateEncoder::FlateEncoder()");
}
zlib_stream.next_out = outBufEnd;
zlib_stream.avail_out = 1; /* anything but 0 to trigger a read */
}
FlateEncoder::~FlateEncoder()
{
deflateEnd(&zlib_stream);
if (str->isEncoder()) {
delete str;
}
}
void FlateEncoder::reset()
{
int zlib_status;
str->reset();
outBufPtr = outBufEnd = outBuf;
inBufEof = outBufEof = false;
deflateEnd(&zlib_stream);
zlib_status = deflateInit(&zlib_stream, Z_DEFAULT_COMPRESSION);
if (zlib_status != Z_OK) {
inBufEof = outBufEof = true;
error(errInternal, -1, "Internal: deflateInit() failed in FlateEncoder::reset()");
}
zlib_stream.next_out = outBufEnd;
zlib_stream.avail_out = 1; /* anything but 0 to trigger a read */
}
bool FlateEncoder::fillBuf()
{
unsigned int starting_avail_out;
int zlib_status;
/* If the output is done, don't try to read more. */
if (outBufEof) {
return false;
}
/* The output buffer should be empty. */
/* If it is not empty, push any processed data to the start. */
if (outBufPtr > outBuf && outBufPtr < outBufEnd) {
const ptrdiff_t n = outBufEnd - outBufPtr;
memmove(outBuf, outBufPtr, n);
outBufEnd = &outBuf[n];
} else {
outBufEnd = outBuf;
}
outBufPtr = outBuf;
/* Keep feeding zlib until we get output. */
/* zlib might consume a few input buffers */
/* before it starts producing output. */
do {
/* avail_out > 0 means that zlib has depleted its input */
/* and needs a new chunk of input in order to generate */
/* more output. */
if (zlib_stream.avail_out != 0) {
/* Fill the input buffer */
const int n = (inBufEof ? 0 : str->doGetChars(inBufSize, inBuf));
if (n == 0) {
inBufEof = true;
}
zlib_stream.next_in = inBuf;
zlib_stream.avail_in = n;
}
/* Ask zlib for output. */
zlib_stream.next_out = outBufEnd;
starting_avail_out = static_cast<unsigned int>(&outBuf[outBufSize] - outBufEnd);
zlib_stream.avail_out = starting_avail_out;
zlib_status = deflate(&zlib_stream, (inBufEof ? Z_FINISH : Z_NO_FLUSH));
if (zlib_status == Z_STREAM_ERROR || zlib_stream.avail_out > starting_avail_out) {
/* Unrecoverable error */
inBufEof = outBufEof = true;
error(errInternal, -1, "Internal: deflate() failed in FlateEncoder::fillBuf()");
return false;
}
} while (zlib_stream.avail_out == outBufSize && !inBufEof);
outBufEnd = &outBuf[outBufSize] - zlib_stream.avail_out;
if (inBufEof && zlib_stream.avail_out != 0) {
outBufEof = true;
}
return outBufPtr < outBufEnd;
}
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