1 files changed, 46 insertions, 10 deletions

diff --git a/other-licenses/snappy/src/snappy.h b/other-licenses/snappy/src/snappy.h
index e4fdad3354..9e0572dcc8 100644
--- a/other-licenses/snappy/src/snappy.h
+++ b/other-licenses/snappy/src/snappy.h
@@ -50,13 +50,36 @@ namespace snappy {
   class Source;
   class Sink;
 
+  struct CompressionOptions {
+    // Compression level.
+    // Level 1 is the fastest
+    // Level 2 is a little slower but provides better compression. Level 2 is
+    // **EXPERIMENTAL** for the time being. It might happen that we decide to
+    // fall back to level 1 in the future.
+    // Levels 3+ are currently not supported. We plan to support levels up to
+    // 9 in the future.
+    // If you played with other compression algorithms, level 1 is equivalent to
+    // fast mode (level 1) of LZ4, level 2 is equivalent to LZ4's level 2 mode
+    // and compresses somewhere around zstd:-3 and zstd:-2 but generally with
+    // faster decompression speeds than snappy:1 and zstd:-3.
+    int level = DefaultCompressionLevel();
+
+    constexpr CompressionOptions() = default;
+    constexpr explicit CompressionOptions(int compression_level)
+        : level(compression_level) {}
+    static constexpr int MinCompressionLevel() { return 1; }
+    static constexpr int MaxCompressionLevel() { return 2; }
+    static constexpr int DefaultCompressionLevel() { return 1; }
+  };
+
   // ------------------------------------------------------------------------
   // Generic compression/decompression routines.
   // ------------------------------------------------------------------------
 
-  // Compress the bytes read from "*source" and append to "*sink". Return the
+  // Compress the bytes read from "*reader" and append to "*writer". Return the
   // number of bytes written.
-  size_t Compress(Source* source, Sink* sink);
+  size_t Compress(Source* reader, Sink* writer,
+                  CompressionOptions options = {});
 
   // Find the uncompressed length of the given stream, as given by the header.
   // Note that the true length could deviate from this; the stream could e.g.
@@ -71,14 +94,22 @@ namespace snappy {
   // Higher-level string based routines (should be sufficient for most users)
   // ------------------------------------------------------------------------
 
-  // Sets "*compressed" to the compressed version of "input[0,input_length-1]".
+  // Sets "*compressed" to the compressed version of "input[0..input_length-1]".
   // Original contents of *compressed are lost.
   //
   // REQUIRES: "input[]" is not an alias of "*compressed".
   size_t Compress(const char* input, size_t input_length,
-                  std::string* compressed);
+                  std::string* compressed, CompressionOptions options = {});
+
+  // Same as `Compress` above but taking an `iovec` array as input. Note that
+  // this function preprocesses the inputs to compute the sum of
+  // `iov[0..iov_cnt-1].iov_len` before reading. To avoid this, use
+  // `RawCompressFromIOVec` below.
+  size_t CompressFromIOVec(const struct iovec* iov, size_t iov_cnt,
+                           std::string* compressed,
+                           CompressionOptions options = {});
 
-  // Decompresses "compressed[0,compressed_length-1]" to "*uncompressed".
+  // Decompresses "compressed[0..compressed_length-1]" to "*uncompressed".
   // Original contents of "*uncompressed" are lost.
   //
   // REQUIRES: "compressed[]" is not an alias of "*uncompressed".
@@ -119,10 +150,15 @@ namespace snappy {
   //    RawCompress(input, input_length, output, &output_length);
   //    ... Process(output, output_length) ...
   //    delete [] output;
-  void RawCompress(const char* input,
-                   size_t input_length,
-                   char* compressed,
-                   size_t* compressed_length);
+  void RawCompress(const char* input, size_t input_length, char* compressed,
+                   size_t* compressed_length, CompressionOptions options = {});
+
+  // Same as `RawCompress` above but taking an `iovec` array as input. Note that
+  // `uncompressed_length` is the total number of bytes to be read from the
+  // elements of `iov` (_not_ the number of elements in `iov`).
+  void RawCompressFromIOVec(const struct iovec* iov, size_t uncompressed_length,
+                            char* compressed, size_t* compressed_length,
+                            CompressionOptions options = {});
 
   // Given data in "compressed[0..compressed_length-1]" generated by
   // calling the Snappy::Compress routine, this routine
@@ -202,7 +238,7 @@ namespace snappy {
   static constexpr int kMinHashTableBits = 8;
   static constexpr size_t kMinHashTableSize = 1 << kMinHashTableBits;
 
-  static constexpr int kMaxHashTableBits = 14;
+  static constexpr int kMaxHashTableBits = 15;
   static constexpr size_t kMaxHashTableSize = 1 << kMaxHashTableBits;
 }  // end namespace snappy