A zlib C++ wrap library

This is a c++ library which will be able to compress/decompress your data buffers. It is a bunch of wrap classes of C library zlib. You need install zlib developer files to your system before you compile library.

Compile and install instructions

Install zlib developer files first

MacOSX

Please install Command-line tools on your OSX system and zlib can be found.

Debian

Use apt-get to Install zlib1g-dev on your system.

sudo apt-get install zlib1g-dev

Compile and install library

Clone source

git clone https://github.com/merainc/gzip_cpp.git

Compile source

cmake . && make

Install library

make install

How to use?

Add header files

#include <gzip_cpp/gzip_cpp.h>

Memory management

Structure to stores memory

gzip::DataBlock is a structures stores memory buffer.

struct DataBlock {
    char *ptr;          // buffer pointer
    std::size_t size;   // size of the buffer
};

typedef std::shared_ptr<DataBlock> Data;

Allocate memory

Invoke gzip::AllocateMemory(std::size_t size) to allocate data buffer and stores to gzip::Data. gzip::Data is a smart pointer it will release buffer automatically, please do not use delete[] Data()->ptr to delete memory.

Memory list

Compressor or decompressor will return a variable of type gzip::DataList to hold processed data. It's a container (std::list) of gzip::Data so you can visit each data block one by one. But you also can use gzip::ExpandDataList(const DataList &data_list) to copy all blocks to one.

Compress data

Construct a compressor

You can construct a default compressor.

gzip::Comp comp;

Also you should check the object is good or not.

if (!comp.IsSucc()) {
  // Failed to create compressor.
  return;
}

You can construct a compressor with compression level. gzip::Comp::Level contains Level::Default, Level::Min, Level::Level_[1~8] and Level::Max. Level::Min means does no compression at all, Level::Max means greatest compression but slowest execution. Use Level::Default equals to Level::Level_6.

gzip::Comp comp(gzip::Comp::Level::Max);

Compress data

Make a gzip::Data object and pass it to gzip::Comp::Process to compress data buffer. If you are compressing the last data block, please pass true for the latest parameter.

gzip::DataList out_data_list = comp.Process(source_data, source_data_size);

Decompress data

Construct a decompressor

You can construct a default decompressor.

gzip::Decomp decomp;

Also you should check the object is good or not.

if (!decomp.IsSucc()) {
  // Failed to create decompressor.
  return;
}

Decompress data

To decompress data by passing a gzip::Data object to method gzip::Decomp::Process, the method returns std::tuple<bool, gzip::DataList> as outcome value. The first boolean value is telling you the uncompress process succeed or not, second gzip::DataList value holds the processed data if succeed.

gzip::Data incoming_data;

// TODO Reading incoming data and store to incoming_data.

boolean succ;
gzip::DataList out_data_list;
std::tie(succ, out_data_list) = decomp.Process(incoming_data);
if (!succ) {
  // Failed to decompress data.
  return;
}

// TODO Processing out_data_list.

Get more information from test.cc

I have built a test case (by using Google Test) and you can run the test after you compile the source code.

./gzip_cpp_test

Test result looks like below

Running main() from gtest_main.cc
[==========] Running 5 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 5 tests from gzip
[ RUN      ] gzip.compress
[       OK ] gzip.compress (0 ms)
[ RUN      ] gzip.decompress
[       OK ] gzip.decompress (0 ms)
[ RUN      ] gzip.invalid_decompress
[       OK ] gzip.invalid_decompress (0 ms)
[ RUN      ] gzip.large_compress
[       OK ] gzip.large_compress (318 ms)
[ RUN      ] gzip.large_decompress
[       OK ] gzip.large_decompress (37 ms)
[----------] 5 tests from gzip (355 ms total)

[----------] Global test environment tear-down
[==========] 5 tests from 1 test case ran. (355 ms total)
[  PASSED  ] 5 tests.

Review test.cc to get more help there or you can just send me a message if you have any question about this library. Check zlib C library document to get more information. If you improve library or fix bug, you are welcome to submit a pull request.