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/* This file is part of Strigi Desktop Search
*
* Copyright (C) 2006 Jos van den Oever <jos@vandenoever.info>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include <strigi/bz2inputstream.h>
#include <bzlib.h>
#include <stdlib.h>
#include <cstring>
using namespace Strigi;
class BZ2InputStream::Private {
public:
BZ2InputStream* const p;
InputStream *input;
bz_stream bzstream;
Private(BZ2InputStream* p, InputStream* i);
~Private();
void dealloc();
void readFromStream();
bool checkMagic();
};
bool
BZ2InputStream::checkHeader(const char* data, int32_t datasize) {
static const char magic[] = {0x42, 0x5a};
static const char compressed_magic[] = {0x31, 0x41, 0x59, 0x26, 0x53, 0x59};
if (datasize < 10) return false;
return (std::memcmp(data, magic, 2) == 0
&& (data[2] == 0x68 || data[2] == 0x30)
&& std::memcmp(data + 4, compressed_magic, 6) == 0);
}
BZ2InputStream::BZ2InputStream(InputStream* input) :p(new Private(this, input)){
}
BZ2InputStream::Private::Private(BZ2InputStream* bis, InputStream* i)
:p(bis), input(i) {
// initialize values that signal state
this->input = input;
// check first bytes of stream before allocating buffer
if (!checkMagic()) {
p->m_error = "Magic bytes for bz2 are wrong.";
p->m_status = Error;
input = NULL;
return;
}
bzstream.bzalloc = NULL;
bzstream.bzfree = NULL;
bzstream.opaque = NULL;
bzstream.avail_in = 0;
bzstream.next_in = NULL;
int r;
r = BZ2_bzDecompressInit(&bzstream, 1, 0);
if (r != BZ_OK) {
p->m_error = "Error initializing BZ2InputStream.";
fprintf(stderr, "Error initializing BZ2InputStream.\n");
dealloc();
p->m_status = Error;
return;
}
// signal that we need to read into the buffer
bzstream.avail_out = 1;
// set the minimum size for the output buffer
p->setMinBufSize(262144);
}
BZ2InputStream::~BZ2InputStream() {
delete p;
}
BZ2InputStream::Private::~Private() {
dealloc();
}
void
BZ2InputStream::Private::dealloc() {
BZ2_bzDecompressEnd(&bzstream);
input = NULL;
}
bool
BZ2InputStream::Private::checkMagic() {
const char* begin;
int32_t nread;
int64_t pos = input->position();
nread = input->read(begin, 10, 0);
input->reset(pos);
if (nread < 10) {
return false;
}
return checkHeader(begin, 10);
}
void
BZ2InputStream::Private::readFromStream() {
// read data from the input stream
const char* inStart;
int32_t nread;
nread = input->read(inStart, 1, 0);
if (nread <= -1) {
p->m_status = Error;
p->m_error = input->error();
} else if (nread < 1) {
p->m_status = Error;
p->m_error = "unexpected end of stream";
} else {
bzstream.next_in = (char*)inStart;
bzstream.avail_in = nread;
}
}
int32_t
BZ2InputStream::fillBuffer(char* start, int32_t space) {
if (p->input == NULL) return -1;
bz_stream& bzstream = p->bzstream;
// make sure there is data to decompress
if (bzstream.avail_out != 0) {
p->readFromStream();
if (m_status != Ok) {
// no data was read
return -1;
}
}
// make sure we can write into the buffer
bzstream.avail_out = space;
bzstream.next_out = start;
// decompress
int r = BZ2_bzDecompress(&bzstream);
// inform the buffer of the number of bytes that was read
int32_t nwritten = space - bzstream.avail_out;
switch (r) {
case BZ_PARAM_ERROR:
m_error = "BZ_PARAM_ERROR";
m_status = Error;
return -1;
case BZ_DATA_ERROR:
m_error = "BZ_DATA_ERROR";
m_status = Error;
return -1;
case BZ_DATA_ERROR_MAGIC:
m_error = "BZ_DATA_ERROR_MAGIC";
m_status = Error;
return -1;
case BZ_MEM_ERROR:
m_error = "BZ_MEM_ERROR";
m_status = Error;
return -1;
case BZ_STREAM_END:
if (bzstream.avail_in) {
p->input->reset(p->input->position()-bzstream.avail_in);
}
// we are finished decompressing,
// (but this stream is not yet finished)
p->dealloc();
}
return nwritten;
}
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