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/**
* Copyright (c) 2021, Timothy Stack
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Timothy Stack nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @file lnav.gzip.cc
*/
#include "lnav.gzip.hh"
#include <zlib.h>
#include "config.h"
#include "fmt/format.h"
namespace lnav {
namespace gzip {
bool
is_gzipped(const char* buffer, size_t len)
{
return len > 2 && buffer[0] == '\037' && buffer[1] == '\213';
}
Result<auto_buffer, std::string>
compress(const void* input, size_t len)
{
auto retval = auto_buffer::alloc(len + 4096);
z_stream zs;
zs.zalloc = Z_NULL;
zs.zfree = Z_NULL;
zs.opaque = Z_NULL;
zs.avail_in = (uInt) len;
zs.next_in = (Bytef*) input;
zs.avail_out = (uInt) retval.capacity();
zs.next_out = (Bytef*) retval.in();
zs.total_out = 0;
auto rc = deflateInit2(
&zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 15 | 16, 8, Z_DEFAULT_STRATEGY);
if (rc != Z_OK) {
return Err(fmt::format(
FMT_STRING("unable to initialize compressor -- {}"), zError(rc)));
}
rc = deflate(&zs, Z_FINISH);
if (rc != Z_STREAM_END) {
return Err(fmt::format(FMT_STRING("unable to compress data -- {}"),
zError(rc)));
}
rc = deflateEnd(&zs);
if (rc != Z_OK) {
return Err(fmt::format(
FMT_STRING("unable to finalize compression -- {}"), zError(rc)));
}
return Ok(std::move(retval.resize(zs.total_out)));
}
Result<auto_buffer, std::string>
uncompress(const std::string& src, const void* buffer, size_t size)
{
auto uncomp = auto_buffer::alloc(size * 2);
z_stream strm;
int err;
strm.next_in = (Bytef*) buffer;
strm.msg = Z_NULL;
strm.avail_in = size;
strm.total_in = 0;
strm.total_out = 0;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
if ((err = inflateInit2(&strm, (16 + MAX_WBITS))) != Z_OK) {
return Err(fmt::format(FMT_STRING("invalid gzip data: {} -- {}"),
src,
strm.msg ? strm.msg : zError(err)));
}
bool done = false;
while (!done) {
if (strm.total_out >= uncomp.size()) {
uncomp.expand_by(size / 2);
}
strm.next_out = (Bytef*) (uncomp.in() + strm.total_out);
strm.avail_out = uncomp.capacity() - strm.total_out;
// Inflate another chunk.
err = inflate(&strm, Z_SYNC_FLUSH);
if (err == Z_STREAM_END) {
done = true;
} else if (err != Z_OK) {
inflateEnd(&strm);
return Err(fmt::format(FMT_STRING("unable to uncompress: {} -- {}"),
src,
strm.msg ? strm.msg : zError(err)));
}
}
if (inflateEnd(&strm) != Z_OK) {
return Err(fmt::format(FMT_STRING("unable to uncompress: {} -- {}"),
src,
strm.msg ? strm.msg : zError(err)));
}
return Ok(std::move(uncomp.resize(strm.total_out)));
}
} // namespace gzip
} // namespace lnav
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