Restore old compression functions to preserve ABI

Fixes #183

snappy.h

@@ -78,8 +78,10 @@ namespace snappy {
 
   // Compress the bytes read from "*reader" and append to "*writer". Return the
   // number of bytes written.
+  // First version is to preserve ABI.
+  size_t Compress(Source* reader, Sink* writer);
   size_t Compress(Source* reader, Sink* writer,
-                  CompressionOptions options = {});
+                  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.
@@ -98,16 +100,22 @@ namespace snappy {
   // Original contents of *compressed are lost.
   //
   // REQUIRES: "input[]" is not an alias of "*compressed".
+  // First version is to preserve ABI.
   size_t Compress(const char* input, size_t input_length,
-                  std::string* compressed, CompressionOptions options = {});
+                  std::string* compressed);
+  size_t Compress(const char* input, size_t input_length,
+                  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.
+  // First version is to preserve ABI.
+  size_t CompressFromIOVec(const struct iovec* iov, size_t iov_cnt,
+                           std::string* compressed);
   size_t CompressFromIOVec(const struct iovec* iov, size_t iov_cnt,
                            std::string* compressed,
-                           CompressionOptions options = {});
+                           CompressionOptions options);
 
   // Decompresses "compressed[0..compressed_length-1]" to "*uncompressed".
   // Original contents of "*uncompressed" are lost.
@@ -151,14 +159,18 @@ namespace snappy {
   //    ... Process(output, output_length) ...
   //    delete [] output;
   void RawCompress(const char* input, size_t input_length, char* compressed,
-                   size_t* compressed_length, CompressionOptions options = {});
+                   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);
   void RawCompressFromIOVec(const struct iovec* iov, size_t uncompressed_length,
                             char* compressed, size_t* compressed_length,
-                            CompressionOptions options = {});
+                            CompressionOptions options);
 
   // Given data in "compressed[0..compressed_length-1]" generated by
   // calling the Snappy::Compress routine, this routine