1 //===-- FileSystem.cpp ------------------------------------------*- C++ -*-===//
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 #include "lldb/Host/FileSystem.h"
11 
12 #include "llvm/Support/MD5.h"
13 
14 #include <algorithm>
15 #include <fstream>
16 #include <vector>
17 
18 using namespace lldb;
19 using namespace lldb_private;
20 
21 namespace {
22 
23 bool CalcMD5(const FileSpec &file_spec, uint64_t offset, uint64_t length,
24              llvm::MD5::MD5Result &md5_result) {
25   llvm::MD5 md5_hash;
26   std::ifstream file(file_spec.GetPath(), std::ios::binary);
27   if (!file.is_open())
28     return false;
29 
30   if (offset > 0)
31     file.seekg(offset, file.beg);
32 
33   std::vector<char> read_buf(4096);
34   uint64_t total_read_bytes = 0;
35   while (!file.eof()) {
36     const uint64_t to_read =
37         (length > 0) ? std::min(static_cast<uint64_t>(read_buf.size()),
38                                 length - total_read_bytes)
39                      : read_buf.size();
40     if (to_read == 0)
41       break;
42 
43     file.read(&read_buf[0], to_read);
44     const auto read_bytes = file.gcount();
45     if (read_bytes == 0)
46       break;
47 
48     md5_hash.update(llvm::StringRef(&read_buf[0], read_bytes));
49     total_read_bytes += read_bytes;
50   }
51 
52   md5_hash.final(md5_result);
53   return true;
54 }
55 
56 } // namespace
57 
58 bool FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t &low,
59                               uint64_t &high) {
60   return CalculateMD5(file_spec, 0, 0, low, high);
61 }
62 
63 bool FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t offset,
64                               uint64_t length, uint64_t &low, uint64_t &high) {
65   llvm::MD5::MD5Result md5_result;
66   if (!CalcMD5(file_spec, offset, length, md5_result))
67     return false;
68 
69   const auto uint64_res = reinterpret_cast<const uint64_t *>(md5_result);
70   high = uint64_res[0];
71   low = uint64_res[1];
72 
73   return true;
74 }
75 
76 bool FileSystem::CalculateMD5AsString(const FileSpec &file_spec,
77                                       std::string &digest_str) {
78   return CalculateMD5AsString(file_spec, 0, 0, digest_str);
79 }
80 
81 bool FileSystem::CalculateMD5AsString(const FileSpec &file_spec,
82                                       uint64_t offset, uint64_t length,
83                                       std::string &digest_str) {
84   llvm::MD5::MD5Result md5_result;
85   if (!CalcMD5(file_spec, offset, length, md5_result))
86     return false;
87 
88   llvm::SmallString<32> result_str;
89   llvm::MD5::stringifyResult(md5_result, result_str);
90   digest_str = result_str.c_str();
91   return true;
92 }
93