1 files changed, 72 insertions, 0 deletions
diff --git a/clang/lib/Lex/ScratchBuffer.cpp b/clang/lib/Lex/ScratchBuffer.cpp
new file mode 100644
index 00000000000..99fbdf75654
--- /dev/null
+++ b/clang/lib/Lex/ScratchBuffer.cpp
@@ -0,0 +1,72 @@
+//===--- ScratchBuffer.cpp - Scratch space for forming tokens -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the ScratchBuffer interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/ScratchBuffer.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <cstring>
+using namespace clang;
+
+// ScratchBufSize - The size of each chunk of scratch memory.  Slightly less
+//than a page, almost certainly enough for anything. :)
+static const unsigned ScratchBufSize = 4060;
+
+ScratchBuffer::ScratchBuffer(SourceManager &SM) : SourceMgr(SM), CurBuffer(0) {
+  // Set BytesUsed so that the first call to getToken will require an alloc.
+  BytesUsed = ScratchBufSize;
+  FileID = 0;
+}
+
+/// getToken - Splat the specified text into a temporary MemoryBuffer and
+/// return a SourceLocation that refers to the token.  This is just like the
+/// method below, but returns a location that indicates the physloc of the
+/// token.
+SourceLocation ScratchBuffer::getToken(const char *Buf, unsigned Len) {
+  if (BytesUsed+Len > ScratchBufSize)
+    AllocScratchBuffer(Len);
+  
+  // Copy the token data into the buffer.
+  memcpy(CurBuffer+BytesUsed, Buf, Len);
+
+  // Remember that we used these bytes.
+  BytesUsed += Len;
+
+  assert(BytesUsed-Len < (1 << SourceLocation::FilePosBits) &&
+         "Out of range file position!");
+  
+  return SourceLocation::getFileLoc(FileID, BytesUsed-Len);
+}
+
+
+/// getToken - Splat the specified text into a temporary MemoryBuffer and
+/// return a SourceLocation that refers to the token.  The SourceLoc value
+/// gives a virtual location that the token will appear to be from.
+SourceLocation ScratchBuffer::getToken(const char *Buf, unsigned Len,
+                                       SourceLocation SourceLoc) {
+  // Map the physloc to the specified sourceloc.
+  return SourceMgr.getInstantiationLoc(getToken(Buf, Len), SourceLoc);
+}
+
+void ScratchBuffer::AllocScratchBuffer(unsigned RequestLen) {
+  // Only pay attention to the requested length if it is larger than our default
+  // page size.  If it is, we allocate an entire chunk for it.  This is to
+  // support gigantic tokens, which almost certainly won't happen. :)
+  if (RequestLen < ScratchBufSize)
+    RequestLen = ScratchBufSize;
+  
+  llvm::MemoryBuffer *Buf = 
+    llvm::MemoryBuffer::getNewMemBuffer(RequestLen, "<scratch space>");
+  FileID = SourceMgr.createFileIDForMemBuffer(Buf);
+  CurBuffer = const_cast<char*>(Buf->getBufferStart());
+  BytesUsed = 0;
+}