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129 lines
3.0 KiB
C++
129 lines
3.0 KiB
C++
#include "webcc/zlib_wrapper.h"
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#include <cassert>
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#include <utility> // std::move
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#include "zlib.h"
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#include "webcc/logger.h"
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namespace webcc {
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bool Compress(const std::string& input, std::string* output) {
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output->clear();
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if (input.empty()) {
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return true;
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}
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z_stream stream;
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stream.next_in = (Bytef*)input.data();
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stream.avail_in = (uInt)input.size();
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stream.zalloc = Z_NULL;
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stream.zfree = Z_NULL;
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stream.opaque = Z_NULL;
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int ret = deflateInit2(&stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
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MAX_WBITS + 16, 8, Z_DEFAULT_STRATEGY);
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if (ret != Z_OK) {
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return false;
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}
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std::string buf;
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buf.resize(input.size() / 2); // TODO
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// Run deflate() on input until output buffer is not full.
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do {
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stream.avail_out = (uInt)buf.size();
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stream.next_out = (Bytef*)buf.data();
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int err = deflate(&stream, Z_FINISH);
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assert(err != Z_STREAM_ERROR);
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if (err != Z_OK) {
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deflateEnd(&stream);
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if (stream.msg != nullptr) {
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LOG_ERRO("zlib deflate error: %s", stream.msg);
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}
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return false;
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}
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std::size_t size = buf.size() - stream.avail_out;
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output->insert(output->end(), buf.data(), buf.data() + size);
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} while (stream.avail_out == 0);
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if (deflateEnd(&stream) != Z_OK) {
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return false;
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}
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return true;
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}
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// Modified from:
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// http://windrealm.org/tutorials/decompress-gzip-stream.php
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bool Decompress(const std::string& input, std::string* output) {
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output->clear();
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if (input.empty()) {
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return true;
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}
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// Initialize the output buffer with the same size as the input.
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std::string buf;
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buf.resize(input.size());
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z_stream stream;
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stream.next_in = (Bytef*)input.data();
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stream.avail_in = (uInt)input.size();
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stream.total_out = 0;
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stream.zalloc = Z_NULL;
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stream.zfree = Z_NULL;
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// About the windowBits paramter:
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// (https://stackoverflow.com/a/1838702)
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// (http://www.zlib.net/manual.html)
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// windowBits can also be greater than 15 for optional gzip decoding. Add 32
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// to windowBits to enable zlib and gzip decoding with automatic header
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// detection, or add 16 to decode only the gzip format (the zlib format will
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// return a Z_DATA_ERROR).
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if (inflateInit2(&stream, MAX_WBITS + 32) != Z_OK) {
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return false;
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}
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while (true) {
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// Enlarge the output buffer if it's too small.
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if (stream.total_out >= buf.size()) {
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buf.resize(buf.size() + input.size() / 2);
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}
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stream.next_out = (Bytef*)(buf.data() + stream.total_out);
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stream.avail_out = (uInt)buf.size() - stream.total_out;
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// Inflate another chunk.
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int err = inflate(&stream, Z_SYNC_FLUSH);
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if (err == Z_STREAM_END) {
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break;
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} else if (err != Z_OK) {
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inflateEnd(&stream);
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if (stream.msg != nullptr) {
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LOG_ERRO("zlib inflate error: %s", stream.msg);
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}
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return false;
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}
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}
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if (inflateEnd(&stream) != Z_OK) {
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return false;
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}
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// Remove the unused part then move to the output
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buf.erase(stream.total_out);
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*output = std::move(buf);
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return true;
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}
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} // namespace webcc
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