1 files changed, 93 insertions, 0 deletions
diff --git a/third_party/llvm-project/LineIterator.cpp b/third_party/llvm-project/LineIterator.cpp
new file mode 100644
index 000000000..164436a2c
--- /dev/null
+++ b/third_party/llvm-project/LineIterator.cpp
@@ -0,0 +1,93 @@
+//===- LineIterator.cpp - Implementation of line iteration ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/LineIterator.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+using namespace llvm;
+
+static bool isAtLineEnd(const char *P) {
+  if (*P == '\n')
+    return true;
+  if (*P == '\r' && *(P + 1) == '\n')
+    return true;
+  return false;
+}
+
+static bool skipIfAtLineEnd(const char *&P) {
+  if (*P == '\n') {
+    ++P;
+    return true;
+  }
+  if (*P == '\r' && *(P + 1) == '\n') {
+    P += 2;
+    return true;
+  }
+  return false;
+}
+
+line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
+                             char CommentMarker)
+    : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
+      CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
+      CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
+                  0) {
+  // Ensure that if we are constructed on a non-empty memory buffer that it is
+  // a null terminated buffer.
+  if (Buffer.getBufferSize()) {
+    assert(Buffer.getBufferEnd()[0] == '\0');
+    // Make sure we don't skip a leading newline if we're keeping blanks
+    if (SkipBlanks || !isAtLineEnd(Buffer.getBufferStart()))
+      advance();
+  }
+}
+
+void line_iterator::advance() {
+  assert(Buffer && "Cannot advance past the end!");
+
+  const char *Pos = CurrentLine.end();
+  assert(Pos == Buffer->getBufferStart() || isAtLineEnd(Pos) || *Pos == '\0');
+
+  if (skipIfAtLineEnd(Pos))
+    ++LineNumber;
+  if (!SkipBlanks && isAtLineEnd(Pos)) {
+    // Nothing to do for a blank line.
+  } else if (CommentMarker == '\0') {
+    // If we're not stripping comments, this is simpler.
+    while (skipIfAtLineEnd(Pos))
+      ++LineNumber;
+  } else {
+    // Skip comments and count line numbers, which is a bit more complex.
+    for (;;) {
+      if (isAtLineEnd(Pos) && !SkipBlanks)
+        break;
+      if (*Pos == CommentMarker)
+        do {
+          ++Pos;
+        } while (*Pos != '\0' && !isAtLineEnd(Pos));
+      if (!skipIfAtLineEnd(Pos))
+        break;
+      ++LineNumber;
+    }
+  }
+
+  if (*Pos == '\0') {
+    // We've hit the end of the buffer, reset ourselves to the end state.
+    Buffer = nullptr;
+    CurrentLine = StringRef();
+    return;
+  }
+
+  // Measure the line.
+  size_t Length = 0;
+  while (Pos[Length] != '\0' && !isAtLineEnd(&Pos[Length])) {
+    ++Length;
+  }
+
+  CurrentLine = StringRef(Pos, Length);
+}