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1 : // Protocol Buffers - Google's data interchange format
2 : // Copyright 2012 Google Inc. All rights reserved.
3 : // https://developers.google.com/protocol-buffers/
4 : //
5 : // Redistribution and use in source and binary forms, with or without
6 : // modification, are permitted provided that the following conditions are
7 : // met:
8 : //
9 : // * Redistributions of source code must retain the above copyright
10 : // notice, this list of conditions and the following disclaimer.
11 : // * Redistributions in binary form must reproduce the above
12 : // copyright notice, this list of conditions and the following disclaimer
13 : // in the documentation and/or other materials provided with the
14 : // distribution.
15 : // * Neither the name of Google Inc. nor the names of its
16 : // contributors may be used to endorse or promote products derived from
17 : // this software without specific prior written permission.
18 : //
19 : // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 : // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 : // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 : // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 : // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 : // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 : // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 : // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 : // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 : // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 : // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 :
31 : // from google3/base/stringprintf.cc
32 :
33 : #include <google/protobuf/stubs/stringprintf.h>
34 :
35 : #include <errno.h>
36 : #include <stdarg.h> // For va_list and related operations
37 : #include <stdio.h> // MSVC requires this for _vsnprintf
38 : #include <vector>
39 : #include <google/protobuf/stubs/common.h>
40 :
41 : namespace google {
42 : namespace protobuf {
43 :
44 : #ifdef _MSC_VER
45 : enum { IS_COMPILER_MSVC = 1 };
46 : #ifndef va_copy
47 : // Define va_copy for MSVC. This is a hack, assuming va_list is simply a
48 : // pointer into the stack and is safe to copy.
49 : #define va_copy(dest, src) ((dest) = (src))
50 : #endif
51 : #else
52 : enum { IS_COMPILER_MSVC = 0 };
53 : #endif
54 :
55 0 : void StringAppendV(string* dst, const char* format, va_list ap) {
56 : // First try with a small fixed size buffer
57 : static const int kSpaceLength = 1024;
58 : char space[kSpaceLength];
59 :
60 : // It's possible for methods that use a va_list to invalidate
61 : // the data in it upon use. The fix is to make a copy
62 : // of the structure before using it and use that copy instead.
63 : va_list backup_ap;
64 0 : va_copy(backup_ap, ap);
65 0 : int result = vsnprintf(space, kSpaceLength, format, backup_ap);
66 0 : va_end(backup_ap);
67 :
68 0 : if (result < kSpaceLength) {
69 0 : if (result >= 0) {
70 : // Normal case -- everything fit.
71 0 : dst->append(space, result);
72 0 : return;
73 : }
74 :
75 : if (IS_COMPILER_MSVC) {
76 : // Error or MSVC running out of space. MSVC 8.0 and higher
77 : // can be asked about space needed with the special idiom below:
78 : va_copy(backup_ap, ap);
79 : result = vsnprintf(NULL, 0, format, backup_ap);
80 : va_end(backup_ap);
81 : }
82 :
83 0 : if (result < 0) {
84 : // Just an error.
85 0 : return;
86 : }
87 : }
88 :
89 : // Increase the buffer size to the size requested by vsnprintf,
90 : // plus one for the closing \0.
91 0 : int length = result+1;
92 0 : char* buf = new char[length];
93 :
94 : // Restore the va_list before we use it again
95 0 : va_copy(backup_ap, ap);
96 0 : result = vsnprintf(buf, length, format, backup_ap);
97 0 : va_end(backup_ap);
98 :
99 0 : if (result >= 0 && result < length) {
100 : // It fit
101 0 : dst->append(buf, result);
102 : }
103 0 : delete[] buf;
104 : }
105 :
106 :
107 0 : string StringPrintf(const char* format, ...) {
108 : va_list ap;
109 0 : va_start(ap, format);
110 0 : string result;
111 0 : StringAppendV(&result, format, ap);
112 0 : va_end(ap);
113 0 : return result;
114 : }
115 :
116 0 : const string& SStringPrintf(string* dst, const char* format, ...) {
117 : va_list ap;
118 0 : va_start(ap, format);
119 0 : dst->clear();
120 0 : StringAppendV(dst, format, ap);
121 0 : va_end(ap);
122 0 : return *dst;
123 : }
124 :
125 0 : void StringAppendF(string* dst, const char* format, ...) {
126 : va_list ap;
127 0 : va_start(ap, format);
128 0 : StringAppendV(dst, format, ap);
129 0 : va_end(ap);
130 0 : }
131 :
132 : // Max arguments supported by StringPrintVector
133 : const int kStringPrintfVectorMaxArgs = 32;
134 :
135 : // An empty block of zero for filler arguments. This is const so that if
136 : // printf tries to write to it (via %n) then the program gets a SIGSEGV
137 : // and we can fix the problem or protect against an attack.
138 : static const char string_printf_empty_block[256] = { '\0' };
139 :
140 0 : string StringPrintfVector(const char* format, const vector<string>& v) {
141 0 : GOOGLE_CHECK_LE(v.size(), kStringPrintfVectorMaxArgs)
142 0 : << "StringPrintfVector currently only supports up to "
143 0 : << kStringPrintfVectorMaxArgs << " arguments. "
144 0 : << "Feel free to add support for more if you need it.";
145 :
146 : // Add filler arguments so that bogus format+args have a harder time
147 : // crashing the program, corrupting the program (%n),
148 : // or displaying random chunks of memory to users.
149 :
150 : const char* cstr[kStringPrintfVectorMaxArgs];
151 0 : for (int i = 0; i < v.size(); ++i) {
152 0 : cstr[i] = v[i].c_str();
153 : }
154 0 : for (int i = v.size(); i < GOOGLE_ARRAYSIZE(cstr); ++i) {
155 0 : cstr[i] = &string_printf_empty_block[0];
156 : }
157 :
158 : // I do not know any way to pass kStringPrintfVectorMaxArgs arguments,
159 : // or any way to build a va_list by hand, or any API for printf
160 : // that accepts an array of arguments. The best I can do is stick
161 : // this COMPILE_ASSERT right next to the actual statement.
162 :
163 : GOOGLE_COMPILE_ASSERT(kStringPrintfVectorMaxArgs == 32, arg_count_mismatch);
164 : return StringPrintf(format,
165 : cstr[0], cstr[1], cstr[2], cstr[3], cstr[4],
166 : cstr[5], cstr[6], cstr[7], cstr[8], cstr[9],
167 : cstr[10], cstr[11], cstr[12], cstr[13], cstr[14],
168 : cstr[15], cstr[16], cstr[17], cstr[18], cstr[19],
169 : cstr[20], cstr[21], cstr[22], cstr[23], cstr[24],
170 : cstr[25], cstr[26], cstr[27], cstr[28], cstr[29],
171 0 : cstr[30], cstr[31]);
172 : }
173 : } // namespace protobuf
174 : } // namespace google
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