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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 : #include <google/protobuf/testing/googletest.h>
41 :
42 : namespace google {
43 : namespace protobuf {
44 :
45 : #ifdef _MSC_VER
46 : enum { IS_COMPILER_MSVC = 1 };
47 : #ifndef va_copy
48 : // Define va_copy for MSVC. This is a hack, assuming va_list is simply a
49 : // pointer into the stack and is safe to copy.
50 : #define va_copy(dest, src) ((dest) = (src))
51 : #endif
52 : #else
53 : enum { IS_COMPILER_MSVC = 0 };
54 : #endif
55 :
56 0 : void StringAppendV(string* dst, const char* format, va_list ap) {
57 : // First try with a small fixed size buffer
58 : static const int kSpaceLength = 1024;
59 : char space[kSpaceLength];
60 :
61 : // It's possible for methods that use a va_list to invalidate
62 : // the data in it upon use. The fix is to make a copy
63 : // of the structure before using it and use that copy instead.
64 : va_list backup_ap;
65 0 : va_copy(backup_ap, ap);
66 0 : int result = vsnprintf(space, kSpaceLength, format, backup_ap);
67 0 : va_end(backup_ap);
68 :
69 0 : if (result < kSpaceLength) {
70 0 : if (result >= 0) {
71 : // Normal case -- everything fit.
72 0 : dst->append(space, result);
73 0 : return;
74 : }
75 :
76 : if (IS_COMPILER_MSVC) {
77 : // Error or MSVC running out of space. MSVC 8.0 and higher
78 : // can be asked about space needed with the special idiom below:
79 : va_copy(backup_ap, ap);
80 : result = vsnprintf(NULL, 0, format, backup_ap);
81 : va_end(backup_ap);
82 : }
83 :
84 0 : if (result < 0) {
85 : // Just an error.
86 : return;
87 : }
88 : }
89 :
90 : // Increase the buffer size to the size requested by vsnprintf,
91 : // plus one for the closing \0.
92 0 : int length = result+1;
93 0 : char* buf = new char[length];
94 :
95 : // Restore the va_list before we use it again
96 0 : va_copy(backup_ap, ap);
97 0 : result = vsnprintf(buf, length, format, backup_ap);
98 0 : va_end(backup_ap);
99 :
100 0 : if (result >= 0 && result < length) {
101 : // It fit
102 0 : dst->append(buf, result);
103 : }
104 0 : delete[] buf;
105 : }
106 :
107 :
108 0 : string StringPrintf(const char* format, ...) {
109 : va_list ap;
110 0 : va_start(ap, format);
111 : string result;
112 0 : StringAppendV(&result, format, ap);
113 0 : va_end(ap);
114 0 : return result;
115 : }
116 :
117 0 : const string& SStringPrintf(string* dst, const char* format, ...) {
118 : va_list ap;
119 0 : va_start(ap, format);
120 : dst->clear();
121 0 : StringAppendV(dst, format, ap);
122 0 : va_end(ap);
123 0 : return *dst;
124 : }
125 :
126 0 : void StringAppendF(string* dst, const char* format, ...) {
127 : va_list ap;
128 0 : va_start(ap, format);
129 0 : StringAppendV(dst, format, ap);
130 0 : va_end(ap);
131 0 : }
132 :
133 : // Max arguments supported by StringPrintVector
134 : const int kStringPrintfVectorMaxArgs = 32;
135 :
136 : // An empty block of zero for filler arguments. This is const so that if
137 : // printf tries to write to it (via %n) then the program gets a SIGSEGV
138 : // and we can fix the problem or protect against an attack.
139 : static const char string_printf_empty_block[256] = { '\0' };
140 :
141 0 : string StringPrintfVector(const char* format, const vector<string>& v) {
142 0 : GOOGLE_CHECK_LE(v.size(), kStringPrintfVectorMaxArgs)
143 0 : << "StringPrintfVector currently only supports up to "
144 0 : << kStringPrintfVectorMaxArgs << " arguments. "
145 0 : << "Feel free to add support for more if you need it.";
146 :
147 : // Add filler arguments so that bogus format+args have a harder time
148 : // crashing the program, corrupting the program (%n),
149 : // or displaying random chunks of memory to users.
150 :
151 : const char* cstr[kStringPrintfVectorMaxArgs];
152 0 : for (int i = 0; i < v.size(); ++i) {
153 0 : cstr[i] = v[i].c_str();
154 : }
155 0 : for (int i = v.size(); i < GOOGLE_ARRAYSIZE(cstr); ++i) {
156 0 : cstr[i] = &string_printf_empty_block[0];
157 : }
158 :
159 : // I do not know any way to pass kStringPrintfVectorMaxArgs arguments,
160 : // or any way to build a va_list by hand, or any API for printf
161 : // that accepts an array of arguments. The best I can do is stick
162 : // this COMPILE_ASSERT right next to the actual statement.
163 :
164 : GOOGLE_COMPILE_ASSERT(kStringPrintfVectorMaxArgs == 32, arg_count_mismatch);
165 : return StringPrintf(format,
166 : cstr[0], cstr[1], cstr[2], cstr[3], cstr[4],
167 : cstr[5], cstr[6], cstr[7], cstr[8], cstr[9],
168 : cstr[10], cstr[11], cstr[12], cstr[13], cstr[14],
169 : cstr[15], cstr[16], cstr[17], cstr[18], cstr[19],
170 : cstr[20], cstr[21], cstr[22], cstr[23], cstr[24],
171 : cstr[25], cstr[26], cstr[27], cstr[28], cstr[29],
172 0 : cstr[30], cstr[31]);
173 : }
174 : } // namespace protobuf
175 : } // namespace google
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