minetestmapper/ZlibDecompressor.cpp
sfan5 8e83ce6464 Some more code modernization
also a few small performance improvements
2020-05-08 22:16:13 +02:00

62 lines
1.2 KiB
C++

#include <zlib.h>
#include <stdint.h>
#include "ZlibDecompressor.h"
ZlibDecompressor::ZlibDecompressor(const unsigned char *data, std::size_t size):
m_data(data),
m_seekPos(0),
m_size(size)
{
}
ZlibDecompressor::~ZlibDecompressor()
{
}
void ZlibDecompressor::setSeekPos(std::size_t seekPos)
{
m_seekPos = seekPos;
}
std::size_t ZlibDecompressor::seekPos() const
{
return m_seekPos;
}
ustring ZlibDecompressor::decompress()
{
const unsigned char *data = m_data + m_seekPos;
const std::size_t size = m_size - m_seekPos;
ustring buffer;
constexpr size_t BUFSIZE = 128 * 1024;
unsigned char temp_buffer[BUFSIZE];
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.next_in = Z_NULL;
strm.avail_in = size;
if (inflateInit(&strm) != Z_OK)
throw DecompressError();
strm.next_in = const_cast<unsigned char *>(data);
int ret = 0;
do {
strm.avail_out = BUFSIZE;
strm.next_out = temp_buffer;
ret = inflate(&strm, Z_NO_FLUSH);
buffer.append(temp_buffer, BUFSIZE - strm.avail_out);
} while (ret == Z_OK);
if (ret != Z_STREAM_END)
throw DecompressError();
m_seekPos += strm.next_in - data;
(void)inflateEnd(&strm);
return buffer;
}