1//===--- Compression.cpp - Compression implementation ---------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements compression functions.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Support/Compression.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/Config/config.h"
17#include "llvm/Support/Compiler.h"
18#include "llvm/Support/ErrorHandling.h"
19#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
20#include <zlib.h>
21#endif
22
23using namespace llvm;
24
25#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
26static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
27  switch (Level) {
28    case zlib::NoCompression: return 0;
29    case zlib::BestSpeedCompression: return 1;
30    case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
31    case zlib::BestSizeCompression: return 9;
32  }
33  llvm_unreachable("Invalid zlib::CompressionLevel!");
34}
35
36static zlib::Status encodeZlibReturnValue(int ReturnValue) {
37  switch (ReturnValue) {
38    case Z_OK: return zlib::StatusOK;
39    case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
40    case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
41    case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
42    case Z_DATA_ERROR: return zlib::StatusInvalidData;
43    default: llvm_unreachable("unknown zlib return status!");
44  }
45}
46
47bool zlib::isAvailable() { return true; }
48zlib::Status zlib::compress(StringRef InputBuffer,
49                            SmallVectorImpl<char> &CompressedBuffer,
50                            CompressionLevel Level) {
51  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
52  CompressedBuffer.resize(CompressedSize);
53  int CLevel = encodeZlibCompressionLevel(Level);
54  Status Res = encodeZlibReturnValue(::compress2(
55      (Bytef *)CompressedBuffer.data(), &CompressedSize,
56      (const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
57  CompressedBuffer.resize(CompressedSize);
58  return Res;
59}
60
61zlib::Status zlib::uncompress(StringRef InputBuffer,
62                              SmallVectorImpl<char> &UncompressedBuffer,
63                              size_t UncompressedSize) {
64  UncompressedBuffer.resize(UncompressedSize);
65  Status Res = encodeZlibReturnValue(::uncompress(
66      (Bytef *)UncompressedBuffer.data(), (uLongf *)&UncompressedSize,
67      (const Bytef *)InputBuffer.data(), InputBuffer.size()));
68  UncompressedBuffer.resize(UncompressedSize);
69  return Res;
70}
71
72uint32_t zlib::crc32(StringRef Buffer) {
73  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
74}
75
76#else
77bool zlib::isAvailable() { return false; }
78zlib::Status zlib::compress(StringRef InputBuffer,
79                            SmallVectorImpl<char> &CompressedBuffer,
80                            CompressionLevel Level) {
81  return zlib::StatusUnsupported;
82}
83zlib::Status zlib::uncompress(StringRef InputBuffer,
84                              SmallVectorImpl<char> &UncompressedBuffer,
85                              size_t UncompressedSize) {
86  return zlib::StatusUnsupported;
87}
88uint32_t zlib::crc32(StringRef Buffer) {
89  llvm_unreachable("zlib::crc32 is unavailable");
90}
91#endif
92
93