Support Zstd compression level in Leveldb

PiperOrigin-RevId: 520556840

2 files changed, 8 insertions, 2 deletions

diff --git a/port/port_example.h b/port/port_example.h
index b1a1c32..5d50ffa 100644
--- a/port/port_example.h
+++ b/port/port_example.h
@@ -83,7 +83,8 @@ bool Snappy_Uncompress(const char* input_data, size_t input_length,
 
 // Store the zstd compression of "input[0,input_length-1]" in *output.
 // Returns false if zstd is not supported by this port.
-bool Zstd_Compress(const char* input, size_t input_length, std::string* output);
+bool Zstd_Compress(int level, const char* input, size_t input_length,
+                   std::string* output);
 
 // If input[0,input_length-1] looks like a valid zstd compressed
 // buffer, store the size of the uncompressed data in *result and
diff --git a/port/port_stdcxx.h b/port/port_stdcxx.h
index ca961e6..6f503f6 100644
--- a/port/port_stdcxx.h
+++ b/port/port_stdcxx.h
@@ -29,6 +29,7 @@
 #include <snappy.h>
 #endif  // HAVE_SNAPPY
 #if HAVE_ZSTD
+#define ZSTD_STATIC_LINKING_ONLY  // For ZSTD_compressionParameters.
 #include <zstd.h>
 #endif  // HAVE_ZSTD
 
@@ -129,7 +130,7 @@ inline bool Snappy_Uncompress(const char* input, size_t length, char* output) {
 #endif  // HAVE_SNAPPY
 }
 
-inline bool Zstd_Compress(const char* input, size_t length,
+inline bool Zstd_Compress(int level, const char* input, size_t length,
                           std::string* output) {
 #if HAVE_ZSTD
   // Get the MaxCompressedLength.
@@ -139,6 +140,9 @@ inline bool Zstd_Compress(const char* input, size_t length,
   }
   output->resize(outlen);
   ZSTD_CCtx* ctx = ZSTD_createCCtx();
+  ZSTD_compressionParameters parameters =
+      ZSTD_getCParams(level, std::max(length, size_t{1}), /*dictSize=*/0);
+  ZSTD_CCtx_setCParams(ctx, parameters);
   outlen = ZSTD_compress2(ctx, &(*output)[0], output->size(), input, length);
   ZSTD_freeCCtx(ctx);
   if (ZSTD_isError(outlen)) {
@@ -148,6 +152,7 @@ inline bool Zstd_Compress(const char* input, size_t length,
   return true;
 #else
   // Silence compiler warnings about unused arguments.
+  (void)level;
   (void)input;
   (void)length;
   (void)output;