Added a blob_compare tool that compares two sbs files that may have the blobs in a different order

PiperOrigin-RevId: 696458888

compression/BUILD.bazel

@@ -259,3 +259,14 @@ cc_binary(
         "@highway//:thread_pool",
     ],
 )
+
+cc_binary(
+    name = "blob_compare",
+    srcs = ["blob_compare.cc"],
+    deps = [
+        ":blob_store",
+        ":io",
+        "@highway//:hwy",
+        "@highway//:hwy_test_util",
+    ],
+)

compression/blob_compare.cc

@@ -0,0 +1,64 @@
+#include <cstdint>
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "compression/blob_store.h"
+#include "compression/io.h"
+#include "hwy/aligned_allocator.h"
+#include "hwy/base.h"
+
+namespace gcpp {
+
+// Compares two sbs files, ignoring the order of the blobs.
+// Gives up on the first mismatch.
+void CompareBlobs(const char* path1, const char* path2) {
+  BlobReader reader1;
+  HWY_ASSERT(reader1.Open(Path(path1)) == 0);
+  BlobReader reader2;
+  HWY_ASSERT(reader2.Open(Path(path2)) == 0);
+  hwy::Span<const hwy::uint128_t> keys1 = reader1.Keys();
+  size_t total_matches = 0;
+  size_t total_fails = 0;
+  for (size_t i = 0; i < keys1.size(); ++i) {
+    fprintf(stderr, "key %s, blob1 size=%zu, blob2 size=%zu\n",
+            StringFromKey(keys1[i]).c_str(), reader1.BlobSize(keys1[i]),
+            reader2.BlobSize(keys1[i]));
+    std::vector<uint8_t> data1(reader1.BlobSize(keys1[i]));
+    HWY_ASSERT(reader1.ReadOne(keys1[i], data1.data(), data1.size()) == 0);
+    HWY_ASSERT(reader2.BlobSize(keys1[i]) == data1.size());
+    std::vector<uint8_t> data2(reader2.BlobSize(keys1[i]));
+    HWY_ASSERT(reader2.ReadOne(keys1[i], data2.data(), data2.size()) == 0);
+    size_t fails = 0;
+    for (size_t j = 0; j < data1.size(); ++j) {
+      if (data1[j] != data2[j]) {
+        if (fails == 0) {
+          fprintf(stderr, "key %s Mismatch at %zu\n",
+                  StringFromKey(keys1[i]).c_str(), j);
+        }
+        ++fails;
+      }
+    }
+    if (fails > 0) {
+      fprintf(stderr, "key %s has %.2f%% Mismatch!\n",
+              StringFromKey(keys1[i]).c_str(), 100.0 * fails / data1.size());
+      ++total_fails;
+    } else {
+      fprintf(stderr, "key %s Matched!\n", StringFromKey(keys1[i]).c_str());
+      ++total_matches;
+    }
+  }
+  fprintf(stderr, "Total matches=%zu, mismatches=%zu\n", total_matches,
+          total_fails);
+}
+
+}  // namespace gcpp
+
+int main(int argc, char** argv) {
+  if (argc != 3) {
+    fprintf(stderr, "Usage: %s <sbs_path> <sbs_path>\n", argv[0]);
+    return 1;
+  }
+  gcpp::CompareBlobs(argv[1], argv[2]);
+  return 0;
+}