Add raw_ostream::write_escaped, for writing escaped strings.

llvm-svn: 84355

1 files changed, 34 insertions, 0 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 0a82cc1d10c..31451ccfdb1 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -168,6 +168,40 @@ raw_ostream &raw_ostream::write_hex(unsigned long long N) {
   return write(CurPtr, EndPtr-CurPtr);
 }
 
+raw_ostream &raw_ostream::write_escaped(StringRef Str) {
+  for (unsigned i = 0, e = Str.size(); i != e; ++i) {
+    unsigned char c = Str[i];
+
+    switch (c) {
+    case '\\':
+      *this << '\\' << '\\';
+      break;
+    case '\t':
+      *this << '\\' << 't';
+      break;
+    case '\n':
+      *this << '\\' << 'n';
+      break;
+    case '"':
+      *this << '\\' << '"';
+      break;
+    default:
+      if (std::isprint(c)) {
+        *this << c;
+        break;
+      }
+
+      // Always expand to a 3-character octal escape.
+      *this << '\\';
+      *this << char('0' + ((c >> 6) & 7));
+      *this << char('0' + ((c >> 3) & 7));
+      *this << char('0' + ((c >> 0) & 7));
+    }
+  }
+
+  return *this;
+}
+
 raw_ostream &raw_ostream::operator<<(const void *P) {
   *this << '0' << 'x';