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
24using namespace llvm;
25
26#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
27static Error createError(StringRef Err) {
28  return make_error<StringError>(Err, inconvertibleErrorCode());
29}
30
31static 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
47bool zlib::isAvailable() { return true; }
48
49Error 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
63Error 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
74Error 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
84uint32_t zlib::crc32(StringRef Buffer) {
85  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
86}
87
88#else
89bool zlib::isAvailable() { return false; }
90Error zlib::compress(StringRef InputBuffer,
91                     SmallVectorImpl<char> &CompressedBuffer, int Level) {
92  llvm_unreachable("zlib::compress is unavailable");
93}
94Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
95                       size_t &UncompressedSize) {
96  llvm_unreachable("zlib::uncompress is unavailable");
97}
98Error zlib::uncompress(StringRef InputBuffer,
99                       SmallVectorImpl<char> &UncompressedBuffer,
100                       size_t UncompressedSize) {
101  llvm_unreachable("zlib::uncompress is unavailable");
102}
103uint32_t zlib::crc32(StringRef Buffer) {
104  llvm_unreachable("zlib::crc32 is unavailable");
105}
106#endif
107