Compression.cpp
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//===--- Compression.cpp - Compression implementation ---------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements compression functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Compression.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Error.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 Error createError(StringRef Err) {
return make_error<StringError>(Err, inconvertibleErrorCode());
}
static StringRef convertZlibCodeToString(int Code) {
switch (Code) {
case Z_MEM_ERROR:
return "zlib error: Z_MEM_ERROR";
case Z_BUF_ERROR:
return "zlib error: Z_BUF_ERROR";
case Z_STREAM_ERROR:
return "zlib error: Z_STREAM_ERROR";
case Z_DATA_ERROR:
return "zlib error: Z_DATA_ERROR";
case Z_OK:
default:
llvm_unreachable("unknown or unexpected zlib status code");
}
}
bool zlib::isAvailable() { return true; }
Error zlib::compress(StringRef InputBuffer,
SmallVectorImpl<char> &CompressedBuffer, int Level) {
unsigned long CompressedSize = ::compressBound(InputBuffer.size());
CompressedBuffer.reserve(CompressedSize);
int Res =
::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size(), Level);
// Tell MemorySanitizer that zlib output buffer is fully initialized.
// This avoids a false report when running LLVM with uninstrumented ZLib.
__msan_unpoison(CompressedBuffer.data(), CompressedSize);
CompressedBuffer.set_size(CompressedSize);
return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
}
Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
size_t &UncompressedSize) {
int Res =
::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 ? createError(convertZlibCodeToString(Res)) : Error::success();
}
Error zlib::uncompress(StringRef InputBuffer,
SmallVectorImpl<char> &UncompressedBuffer,
size_t UncompressedSize) {
UncompressedBuffer.resize(UncompressedSize);
Error E =
uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
UncompressedBuffer.resize(UncompressedSize);
return E;
}
uint32_t zlib::crc32(StringRef Buffer) {
return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
}
#else
bool zlib::isAvailable() { return false; }
Error zlib::compress(StringRef InputBuffer,
SmallVectorImpl<char> &CompressedBuffer, int Level) {
llvm_unreachable("zlib::compress is unavailable");
}
Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
size_t &UncompressedSize) {
llvm_unreachable("zlib::uncompress is unavailable");
}
Error zlib::uncompress(StringRef InputBuffer,
SmallVectorImpl<char> &UncompressedBuffer,
size_t UncompressedSize) {
llvm_unreachable("zlib::uncompress is unavailable");
}
uint32_t zlib::crc32(StringRef Buffer) {
llvm_unreachable("zlib::crc32 is unavailable");
}
#endif