llvm-6502/lib/Support/Compression.cpp
David Blaikie b4074c010b Simplify compression API by compressing into a SmallVector rather than a MemoryBuffer
This is the other half of r205676.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205677 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-05 21:53:04 +00:00

93 lines
3.3 KiB
C++

//===--- Compression.cpp - Compression implementation ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements compression functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Compression.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
#include <zlib.h>
#endif
using namespace llvm;
#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
switch (Level) {
case zlib::NoCompression: return 0;
case zlib::BestSpeedCompression: return 1;
case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
case zlib::BestSizeCompression: return 9;
}
llvm_unreachable("Invalid zlib::CompressionLevel!");
}
static zlib::Status encodeZlibReturnValue(int ReturnValue) {
switch (ReturnValue) {
case Z_OK: return zlib::StatusOK;
case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
case Z_DATA_ERROR: return zlib::StatusInvalidData;
default: llvm_unreachable("unknown zlib return status!");
}
}
bool zlib::isAvailable() { return true; }
zlib::Status zlib::compress(StringRef InputBuffer,
SmallVectorImpl<char> &CompressedBuffer,
CompressionLevel Level) {
unsigned long CompressedSize = ::compressBound(InputBuffer.size());
CompressedBuffer.resize(CompressedSize);
int CLevel = encodeZlibCompressionLevel(Level);
Status Res = encodeZlibReturnValue(::compress2(
(Bytef *)CompressedBuffer.data(), &CompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
CompressedBuffer.resize(CompressedSize);
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()));
UncompressedBuffer.resize(UncompressedSize);
return Res;
}
uint32_t zlib::crc32(StringRef Buffer) {
return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
}
#else
bool zlib::isAvailable() { return false; }
zlib::Status zlib::compress(StringRef InputBuffer,
SmallVectorImpl<char> &CompressedBuffer,
CompressionLevel Level) {
return zlib::StatusUnsupported;
}
zlib::Status zlib::uncompress(StringRef InputBuffer,
SmallVectorImpl<char> &UncompressedBuffer,
size_t UncompressedSize) {
return zlib::StatusUnsupported;
}
uint32_t zlib::crc32(StringRef Buffer) {
llvm_unreachable("zlib::crc32 is unavailable");
}
#endif