[llvm] r281082 - Add a lower level zlib::uncompress.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Fri Sep  9 14:32:36 2016
New Revision: 281082

URL: http://llvm.org/viewvc/llvm-project?rev=281082&view=rev
Log:
Add a lower level zlib::uncompress.

SmallVectors are convenient, but they don't cover every use case.

In particular, they are fairly large (3 pointers + one element) and
there is no way to take ownership of the buffer to put it somewhere
else.  This patch then adds a lower lever interface that works with
any buffer.

Modified:
    llvm/trunk/include/llvm/Support/Compression.h
    llvm/trunk/lib/Support/Compression.cpp

Modified: llvm/trunk/include/llvm/Support/Compression.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compression.h?rev=281082&r1=281081&r2=281082&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Compression.h (original)
+++ llvm/trunk/include/llvm/Support/Compression.h Fri Sep  9 14:32:36 2016
@@ -43,6 +43,9 @@ bool isAvailable();
 Status compress(StringRef InputBuffer, SmallVectorImpl<char> &CompressedBuffer,
                 CompressionLevel Level = DefaultCompression);
 
+Status uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                  size_t &UncompressedSize);
+
 Status uncompress(StringRef InputBuffer,
                   SmallVectorImpl<char> &UncompressedBuffer,
                   size_t UncompressedSize);

Modified: llvm/trunk/lib/Support/Compression.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Compression.cpp?rev=281082&r1=281081&r2=281082&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Compression.cpp (original)
+++ llvm/trunk/lib/Support/Compression.cpp Fri Sep  9 14:32:36 2016
@@ -62,16 +62,23 @@ zlib::Status zlib::compress(StringRef In
   return Res;
 }
 
+zlib::Status zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                              size_t &UncompressedSize) {
+  Status Res = encodeZlibReturnValue(
+      ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
+                   (const Bytef *)InputBuffer.data(), InputBuffer.size()));
+  // Tell MemorySanitizer that zlib output buffer is fully initialized.
+  // This avoids a false report when running LLVM with uninstrumented ZLib.
+  __msan_unpoison(UncompressedBuffer, UncompressedSize);
+  return Res;
+}
+
 zlib::Status zlib::uncompress(StringRef InputBuffer,
                               SmallVectorImpl<char> &UncompressedBuffer,
                               size_t UncompressedSize) {
   UncompressedBuffer.resize(UncompressedSize);
-  Status Res = encodeZlibReturnValue(::uncompress(
-      (Bytef *)UncompressedBuffer.data(), (uLongf *)&UncompressedSize,
-      (const Bytef *)InputBuffer.data(), InputBuffer.size()));
-  // Tell MemorySanitizer that zlib output buffer is fully initialized.
-  // This avoids a false report when running LLVM with uninstrumented ZLib.
-  __msan_unpoison(UncompressedBuffer.data(), UncompressedSize);
+  Status Res =
+      uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
   UncompressedBuffer.resize(UncompressedSize);
   return Res;
 }