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llvm-mirror/lib/Support/Compression.cpp
Petr Hosek 6abbc429da [CMake] Simplify CMake handling for zlib
Rather than handling zlib handling manually, use find_package from CMake
to find zlib properly. Use this to normalize the LLVM_ENABLE_ZLIB,
HAVE_ZLIB, HAVE_ZLIB_H. Furthermore, require zlib if LLVM_ENABLE_ZLIB is
set to YES, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.

This is a reland of abb0075 with all followup changes and fixes that
should address issues that were reported in PR44780.

Differential Revision: https://reviews.llvm.org/D79219
2020-08-11 20:22:11 -07:00

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3.8 KiB
C++

//===--- 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
#include <zlib.h>
#endif
using namespace llvm;
#if LLVM_ENABLE_ZLIB
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.reserve(UncompressedSize);
Error E =
uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
UncompressedBuffer.set_size(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