Br 算法

基于google的brotli开源，实现Br算法。

#include <brotli/encode.h>  
#include <brotli/decode.h>namespace br {/*compress unsigned char* content,if ok return non empty unsigned char * */std::string compress_string(const std::string& content){size_t encoded_size = BrotliEncoderMaxCompressedSize(content.size());std::string compressed_data(encoded_size,0);BROTLI_BOOL result = BrotliEncoderCompress(BROTLI_DEFAULT_QUALITY, BROTLI_DECODER_PARAM_LARGE_WINDOW, BrotliEncoderMode::BROTLI_DEFAULT_MODE, content.size(),(uint8_t *)&content[0],&encoded_size,(uint8_t *)&compressed_data[0]);if (result != BROTLI_TRUE) {return "";}compressed_data.resize(encoded_size);return compressed_data;}/*decompress unsigned char* content,if ok return non empty unsigned char**/std::string decompress_string(const std::string& compressed_data){BrotliDecoderState* pstate = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);if (pstate == nullptr) return "";size_t available_in = compressed_data.size(), total_out = 0;const uint8_t *next_in = (const uint8_t*)&compressed_data[0];std::string uncompress_buf(4096, 0), uncompress_data;BrotliDecoderResult result;do {uint8_t* next_out = (uint8_t*)&uncompress_buf[0];size_t available_out = uncompress_buf.size();size_t temp_total_out = total_out;result = BrotliDecoderDecompressStream(pstate, &available_in, &next_in, &available_out, &next_out, &total_out);if(result != BROTLI_DECODER_RESULT_ERROR)uncompress_data.insert(uncompress_data.end(), uncompress_buf.begin(), uncompress_buf.begin() + (total_out - temp_total_out));} while (result == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT);BrotliDecoderDestroyInstance(pstate);pstate = nullptr;if(result == BROTLI_DECODER_RESULT_SUCCESS)return uncompress_data;return "";}
}

使用brotli git加密数据验证算法：

int main()
{std::cout << "Hello World!\n";std::string str_src = "empty";std::string u8en = br::compress_string(str_src);std::fstream f("F:\\project\\brotli-master\\tests\\testdata\\ukkonooa.compressed",std::fstream::in|std::fstream::binary);std::string stru8;std::getline(f, stru8);std::string u8_src = br::decompress_string(stru8);}