diff options
Diffstat (limited to 'src/mbgl/util/compression.cpp')
-rw-r--r-- | src/mbgl/util/compression.cpp | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/mbgl/util/compression.cpp b/src/mbgl/util/compression.cpp new file mode 100644 index 0000000000..d6d6370546 --- /dev/null +++ b/src/mbgl/util/compression.cpp @@ -0,0 +1,81 @@ +#include <mbgl/util/compression.hpp> + +#include <zlib.h> + +#include <cstring> +#include <stdexcept> + +namespace mbgl { +namespace util { + +std::string compress(const std::string &raw) { + z_stream deflate_stream; + memset(&deflate_stream, 0, sizeof(deflate_stream)); + + // TODO: reuse z_streams + if (deflateInit(&deflate_stream, Z_DEFAULT_COMPRESSION) != Z_OK) { + throw std::runtime_error("failed to initialize deflate"); + } + + deflate_stream.next_in = (Bytef *)raw.data(); + deflate_stream.avail_in = uInt(raw.size()); + + std::string result; + char out[16384]; + + int code; + do { + deflate_stream.next_out = reinterpret_cast<Bytef *>(out); + deflate_stream.avail_out = sizeof(out); + code = deflate(&deflate_stream, Z_FINISH); + if (result.size() < deflate_stream.total_out) { + // append the block to the output string + result.append(out, deflate_stream.total_out - result.size()); + } + } while (code == Z_OK); + + deflateEnd(&deflate_stream); + + if (code != Z_STREAM_END) { + throw std::runtime_error(deflate_stream.msg); + } + + return result; +} + +std::string decompress(const std::string &raw) { + z_stream inflate_stream; + memset(&inflate_stream, 0, sizeof(inflate_stream)); + + // TODO: reuse z_streams + if (inflateInit(&inflate_stream) != Z_OK) { + throw std::runtime_error("failed to initialize inflate"); + } + + inflate_stream.next_in = (Bytef *)raw.data(); + inflate_stream.avail_in = uInt(raw.size()); + + std::string result; + char out[15384]; + + int code; + do { + inflate_stream.next_out = reinterpret_cast<Bytef *>(out); + inflate_stream.avail_out = sizeof(out); + code = inflate(&inflate_stream, 0); + // result.append(out, sizeof(out) - inflate_stream.avail_out); + if (result.size() < inflate_stream.total_out) { + result.append(out, inflate_stream.total_out - result.size()); + } + } while (code == Z_OK); + + inflateEnd(&inflate_stream); + + if (code != Z_STREAM_END) { + throw std::runtime_error(inflate_stream.msg); + } + + return result; +} +} +} |