[zlib-bench] Add compression strategy support

Mainly for my research needs: allow unusal zlib compression strategies
for comparison purposes (R_HUFFMAN_ONLY, Z_RLE).

Bug: 798943
Change-Id: I8a699e68a055df12c08f38d7156769f10f12e90f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2148912
Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Reviewed-by: Adenilson Cavalcanti <cavalcantii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759007}

third_party/zlib/contrib/bench/zlib_bench.cc

@@ -102,7 +102,22 @@ const char* zlib_wrapper_name(zlib_wrapper type) {
   return 0;
 }
 
-static int zlib_compression_level;
+static int zlib_strategy = Z_DEFAULT_STRATEGY;
+
+const char* zlib_level_strategy_name(int compression_level) {
+  if (compression_level == 0)
+    return "";  // strategy is meaningless at level 0
+  if (zlib_strategy == Z_HUFFMAN_ONLY)
+    return "huffman ";
+  if (zlib_strategy == Z_RLE)
+    return "rle ";
+  if (zlib_strategy == Z_DEFAULT_STRATEGY)
+    return "";
+  error_exit("bad strategy", zlib_strategy);
+  return 0;
+}
+
+static int zlib_compression_level = Z_DEFAULT_COMPRESSION;
 
 void zlib_compress(
     const zlib_wrapper type,
@@ -119,7 +134,7 @@ void zlib_compress(
   memset(&stream, 0, sizeof(stream));
 
   int result = deflateInit2(&stream, zlib_compression_level, Z_DEFLATED,
-      zlib_stream_wrapper_type(type), MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+      zlib_stream_wrapper_type(type), MAX_MEM_LEVEL, zlib_strategy);
   if (result != Z_OK)
     error_exit("deflateInit2 failed", result);
 
@@ -185,7 +200,12 @@ void zlib_file(const char* name, const zlib_wrapper type) {
   const auto file = read_file_data_or_exit(name);
   const int length = static_cast<int>(file.size);
   const char* data = file.data.get();
-  printf("%-40s :\n", name);
+
+  /*
+   * Report compression strategy and file name.
+   */
+  const char* strategy = zlib_level_strategy_name(zlib_compression_level);
+  printf("%s%-40s :\n", strategy, name);
 
   /*
    * Chop the data into blocks.
@@ -302,10 +322,18 @@ int main(int argc, char* argv[]) {
   else
     usage_exit(argv[0]);
 
-  if (!get_option(argc, argv, "--compression"))
-    zlib_compression_level = Z_DEFAULT_COMPRESSION;
-  else if (!get_compression(argc, argv, &zlib_compression_level))
-    usage_exit(argv[0]);
+  while (argn < argc && !strncmp(argv[argn], "--", 2)) {
+    if (get_option(argc, argv, "--compression")) {
+      if (!get_compression(argc, argv, &zlib_compression_level))
+        usage_exit(argv[0]);
+    } else if (get_option(argc, argv, "--huffman")) {
+      zlib_strategy = Z_HUFFMAN_ONLY;
+    } else if (get_option(argc, argv, "--rle")) {
+      zlib_strategy = Z_RLE;
+    } else {
+      usage_exit(argv[0]);
+    }
+  }
 
   if (argn >= argc)
     usage_exit(argv[0]);