A number of smaller fixes and performance improvements:

- Implemented Get() directly instead of building on top of a full
  merging iterator stack.  This speeds up the "readrandom" benchmark
  by up to 15-30%.

- Fixed an opensource compilation problem.
  Added --db=<name> flag to control where the database is placed.

- Automatically compact a file when we have done enough
  overlapping seeks to that file.

- Fixed a performance bug where we would read from at least one
  file in a level even if none of the files overlapped the key
  being read.

- Makefile fix for Mac OSX installations that have XCode 4 without XCode 3.

- Unified the two occurrences of binary search in a file-list
  into one routine.

- Found and fixed a bug where we would unnecessarily search the
  last file when looking for a key larger than all data in the
  level.

- A fix to avoid the need for trivial move compactions and
  therefore gets rid of two out of five syncs in "fillseq".

- Removed the MANIFEST file write when switching to a new
  memtable/log-file for a 10-20% improvement on fill speed on ext4.

- Adding a SNAPPY setting in the Makefile for folks who have
  Snappy installed. Snappy compresses values and speeds up writes.



git-svn-id: https://leveldb.googlecode.com/svn/trunk@32 62dab493-f737-651d-591e-8d6aee1b9529

1 files changed, 20 insertions, 2 deletions

diff --git a/port/port_posix.h b/port/port_posix.h
index c158db1..d0b0615 100644
--- a/port/port_posix.h
+++ b/port/port_posix.h
@@ -9,6 +9,9 @@
 
 #include <endian.h>
 #include <pthread.h>
+#ifdef SNAPPY
+#include <snappy.h>
+#endif
 #include <stdint.h>
 #include <string>
 #include <cstdatomic>
@@ -72,15 +75,30 @@ class AtomicPointer {
   }
 };
 
-// TODO(gabor): Implement actual compress
 inline bool Snappy_Compress(const char* input, size_t input_length,
                             std::string* output) {
+#ifdef SNAPPY
+  output->resize(snappy::MaxCompressedLength(input_length));
+  size_t outlen;
+  snappy::RawCompress(input, input_length, &(*output)[0], &outlen);
+  output->resize(outlen);
+  return true;
+#endif
+
   return false;
 }
 
-// TODO(gabor): Implement actual uncompress
 inline bool Snappy_Uncompress(const char* input_data, size_t input_length,
                               std::string* output) {
+#ifdef SNAPPY
+  size_t ulength;
+  if (!snappy::GetUncompressedLength(input_data, ulength, &ulength)) {
+    return false;
+  }
+  output->resize(ulength);
+  return snappy::RawUncompress(input_data, input_length, &(*output)[0]);
+#endif
+
   return false;
 }