1 //===--- Compression.cpp - Compression implementation ---------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements compression functions.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "llvm/Support/Compression.h"
14 #include "llvm/ADT/SmallVector.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/Config/config.h"
17 #include "llvm/Support/Compiler.h"
18 #include "llvm/Support/Error.h"
19 #include "llvm/Support/ErrorHandling.h"
20 #if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
21 #include <zlib.h>
22 #endif
23
24 using namespace llvm;
25
26 #if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
createError(StringRef Err)27 static Error createError(StringRef Err) {
28 return make_error<StringError>(Err, inconvertibleErrorCode());
29 }
30
convertZlibCodeToString(int Code)31 static StringRef convertZlibCodeToString(int Code) {
32 switch (Code) {
33 case Z_MEM_ERROR:
34 return "zlib error: Z_MEM_ERROR";
35 case Z_BUF_ERROR:
36 return "zlib error: Z_BUF_ERROR";
37 case Z_STREAM_ERROR:
38 return "zlib error: Z_STREAM_ERROR";
39 case Z_DATA_ERROR:
40 return "zlib error: Z_DATA_ERROR";
41 case Z_OK:
42 default:
43 llvm_unreachable("unknown or unexpected zlib status code");
44 }
45 }
46
isAvailable()47 bool zlib::isAvailable() { return true; }
48
compress(StringRef InputBuffer,SmallVectorImpl<char> & CompressedBuffer,int Level)49 Error zlib::compress(StringRef InputBuffer,
50 SmallVectorImpl<char> &CompressedBuffer, int Level) {
51 unsigned long CompressedSize = ::compressBound(InputBuffer.size());
52 CompressedBuffer.reserve(CompressedSize);
53 int Res =
54 ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
55 (const Bytef *)InputBuffer.data(), InputBuffer.size(), Level);
56 // Tell MemorySanitizer that zlib output buffer is fully initialized.
57 // This avoids a false report when running LLVM with uninstrumented ZLib.
58 __msan_unpoison(CompressedBuffer.data(), CompressedSize);
59 CompressedBuffer.set_size(CompressedSize);
60 return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
61 }
62
uncompress(StringRef InputBuffer,char * UncompressedBuffer,size_t & UncompressedSize)63 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
64 size_t &UncompressedSize) {
65 int Res =
66 ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
67 (const Bytef *)InputBuffer.data(), InputBuffer.size());
68 // Tell MemorySanitizer that zlib output buffer is fully initialized.
69 // This avoids a false report when running LLVM with uninstrumented ZLib.
70 __msan_unpoison(UncompressedBuffer, UncompressedSize);
71 return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
72 }
73
uncompress(StringRef InputBuffer,SmallVectorImpl<char> & UncompressedBuffer,size_t UncompressedSize)74 Error zlib::uncompress(StringRef InputBuffer,
75 SmallVectorImpl<char> &UncompressedBuffer,
76 size_t UncompressedSize) {
77 UncompressedBuffer.resize(UncompressedSize);
78 Error E =
79 uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
80 UncompressedBuffer.resize(UncompressedSize);
81 return E;
82 }
83
crc32(StringRef Buffer)84 uint32_t zlib::crc32(StringRef Buffer) {
85 return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
86 }
87
88 #else
isAvailable()89 bool zlib::isAvailable() { return false; }
compress(StringRef InputBuffer,SmallVectorImpl<char> & CompressedBuffer,int Level)90 Error zlib::compress(StringRef InputBuffer,
91 SmallVectorImpl<char> &CompressedBuffer, int Level) {
92 llvm_unreachable("zlib::compress is unavailable");
93 }
uncompress(StringRef InputBuffer,char * UncompressedBuffer,size_t & UncompressedSize)94 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
95 size_t &UncompressedSize) {
96 llvm_unreachable("zlib::uncompress is unavailable");
97 }
uncompress(StringRef InputBuffer,SmallVectorImpl<char> & UncompressedBuffer,size_t UncompressedSize)98 Error zlib::uncompress(StringRef InputBuffer,
99 SmallVectorImpl<char> &UncompressedBuffer,
100 size_t UncompressedSize) {
101 llvm_unreachable("zlib::uncompress is unavailable");
102 }
crc32(StringRef Buffer)103 uint32_t zlib::crc32(StringRef Buffer) {
104 llvm_unreachable("zlib::crc32 is unavailable");
105 }
106 #endif
107