[libFuzzer] compute base64 in-process instead of using an external lib. Since libFuzzer should not depend on anything, just re-implement base64 encoder. PR25746

llvm-svn: 254784

llvm/lib/Fuzzer/FuzzerIO.cpp

@@ -91,11 +91,6 @@ std::string DirPlusFile(const std::string &DirPath,
   return DirPath + "/" + FileName;
 }
 
-void PrintFileAsBase64(const std::string &Path) {
-  std::string Cmd = "base64 -w 0 < " + Path + "; echo";
-  ExecuteCommand(Cmd);
-}
-
 void Printf(const char *Fmt, ...) {
   va_list ap;
   va_start(ap, Fmt);

llvm/lib/Fuzzer/FuzzerInternal.h

@@ -42,7 +42,7 @@ void Print(const Unit &U, const char *PrintAfter = "");
 void PrintASCII(const Unit &U, const char *PrintAfter = "");
 std::string Hash(const Unit &U);
 void SetTimer(int Seconds);
-void PrintFileAsBase64(const std::string &Path);
+std::string Base64(const Unit &U);
 int ExecuteCommand(const std::string &Command);
 
 // Private copy of SHA1 implementation.

llvm/lib/Fuzzer/FuzzerLoop.cpp

@@ -302,10 +302,8 @@ void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
   WriteToFile(U, Path);
   Printf("artifact_prefix='%s'; Test unit written to %s\n",
          Options.ArtifactPrefix.c_str(), Path.c_str());
-  if (U.size() <= kMaxUnitSizeToPrint) {
-    Printf("Base64: ");
-    PrintFileAsBase64(Path);
-  }
+  if (U.size() <= kMaxUnitSizeToPrint)
+    Printf("Base64: %s\n", Base64(U).c_str());
 }
 
 void Fuzzer::SaveCorpus() {

llvm/lib/Fuzzer/FuzzerUtil.cpp

@@ -167,4 +167,33 @@ bool ParseDictionaryFile(const std::string &Text, std::vector<Unit> *Units) {
 
 int GetPid() { return getpid(); }
 
+
+std::string Base64(const Unit &U) {
+  static const char Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                              "abcdefghijklmnopqrstuvwxyz"
+                              "0123456789+/";
+  std::string Res;
+  size_t i;
+  for (i = 0; i + 2 < U.size(); i += 3) {
+    uint32_t x = (U[i] << 16) + (U[i + 1] << 8) + U[i + 2];
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += Table[(x >> 6) & 63];
+    Res += Table[x & 63];
+  }
+  if (i + 1 == U.size()) {
+    uint32_t x = (U[i] << 16);
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += "==";
+  } else if (i + 2 == U.size()) {
+    uint32_t x = (U[i] << 16) + (U[i + 1] << 8);
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += Table[(x >> 6) & 63];
+    Res += "=";
+  }
+  return Res;
+}
+
 }  // namespace fuzzer

llvm/lib/Fuzzer/test/FuzzerUnittest.cpp

@@ -360,3 +360,16 @@ TEST(FuzzerDictionary, ParseDictionaryFile) {
   EXPECT_EQ(Units,
             std::vector<Unit>({Unit({'a', 'a'}), Unit({'a', 'b', 'c'})}));
 }
+
+TEST(FuzzerUtil, Base64) {
+  EXPECT_EQ("", Base64({}));
+  EXPECT_EQ("YQ==", Base64({'a'}));
+  EXPECT_EQ("eA==", Base64({'x'}));
+  EXPECT_EQ("YWI=", Base64({'a', 'b'}));
+  EXPECT_EQ("eHk=", Base64({'x', 'y'}));
+  EXPECT_EQ("YWJj", Base64({'a', 'b', 'c'}));
+  EXPECT_EQ("eHl6", Base64({'x', 'y', 'z'}));
+  EXPECT_EQ("YWJjeA==", Base64({'a', 'b', 'c', 'x'}));
+  EXPECT_EQ("YWJjeHk=", Base64({'a', 'b', 'c', 'x', 'y'}));
+  EXPECT_EQ("YWJjeHl6", Base64({'a', 'b', 'c', 'x', 'y', 'z'}));
+}