1 #ifndef IOUTIL_H
2 #define IOUTIL_H 1
3
4 #include <cassert>
5 #include <cerrno>
6 #include <cstdlib>
7 #include <cstring> // for strerror
8 #include <fstream>
9 #include <iostream>
10 #include <limits> // for numeric_limits
11 #include <string>
12
13 /** Print an error message and exit if stream is not good. */
assert_good(const std::ios & stream,const std::string & path)14 static inline void assert_good(const std::ios& stream,
15 const std::string& path)
16 {
17 if (!stream.good()) {
18 std::cerr << "error: `" << path << "': "
19 << strerror(errno) << std::endl;
20 exit(EXIT_FAILURE);
21 }
22 }
23
24 /** Print an error message and exit if stream is not eof. */
assert_eof(std::istream & in,const std::string & path)25 static inline void assert_eof(std::istream& in,
26 const std::string& path)
27 {
28 if (!in.eof()) {
29 in.clear();
30 std::string s;
31 std::getline(in, s);
32 std::cerr << "error: `" << path << "': "
33 "Expected end-of-file and saw `" << s << "'\n";
34 exit(EXIT_FAILURE);
35 }
36 }
37
38 /** This input stream manipulator skips the specified string. */
39 struct expect {
40 const char* s;
expectexpect41 expect(const char* s) : s(s) { }
42 };
43
44 static inline std::istream& operator>>(std::istream& in, expect o)
45 {
46 for (const char* p = o.s; *p != '\0'; ++p) {
47 if (*p == ' ') {
48 in >> std::ws;
49 } else {
50 char c = in.get();
51 if (!in || c != *p) {
52 std::cerr << "error: Expected `" << p
53 << "' and saw ";
54 if (in) {
55 std::cerr << '`' << c << "'\n";
56 std::string s;
57 if (getline(in, s) && !s.empty())
58 std::cerr << "near: " << c << s << '\n';
59 } else if (in.eof())
60 std::cerr << "end-of-file\n";
61 else
62 std::cerr << "I/O error\n";
63 exit(EXIT_FAILURE);
64 }
65 }
66 }
67 return in;
68 }
69
70 /** This input stream manipulator discards characters until reaching
71 * the delimeter. */
72 struct Ignore {
73 const char delim;
74 size_t n;
75 Ignore(const char delim,
76 size_t n = std::numeric_limits<std::streamsize>::max())
delimIgnore77 : delim(delim), n(n) { }
78 };
79
80 static inline std::istream& operator>>(std::istream& in, Ignore o)
81 {
82 return in.ignore(o.n, o.delim);
83 }
84
85 /** Skip the specified character if it's next in the input stream. */
86 struct Skip {
87 char c;
SkipSkip88 Skip(const char c) : c(c) { }
89 };
90
91 static inline std::istream& operator>>(std::istream& in, Skip o)
92 {
93 if (in.peek() == o.c)
94 in.ignore(1);
95 return in;
96 }
97
98 /** Read a file and store it in the specified vector. */
99 template <typename Vector>
readFile(const char * path,Vector & s)100 static inline void readFile(const char* path, Vector& s)
101 {
102 std::ifstream in(path);
103 assert_good(in, path);
104 in.seekg(0, std::ios::end);
105 ssize_t n = in.tellg();
106 assert(n > 0);
107 s.resize(n);
108 in.seekg(0, std::ios::beg);
109 assert_good(in, path);
110 char *p = reinterpret_cast<char*>(&s[0]);
111 #if __MACH__
112 // Read 1 GB at a time. Reads of 2 GB or more fail.
113 const ssize_t N = 1024 * 1024 * 1024;
114 for (; n > N; n -= N, p += N) {
115 in.read(p, N);
116 assert_good(in, path);
117 assert(in.gcount() == N);
118 }
119 #endif
120 in.read(p, n);
121 assert_good(in, path);
122 assert(in.gcount() == n);
123 }
124
125 /** Copy a file */
copyFile(const std::string & srcPath,const std::string & dstPath)126 inline static void copyFile(const std::string& srcPath,
127 const std::string& dstPath)
128 {
129 assert(srcPath != dstPath);
130 std::ifstream src(srcPath.c_str(), std::ios::binary);
131 std::ofstream dst(dstPath.c_str(), std::ios::binary);
132 dst << src.rdbuf();
133 assert(dst);
134 }
135
136 #endif
137