gtest-printers.cc
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29 //
30 // Author: wan@google.com (Zhanyong Wan)
31 
32 // Google Test - The Google C++ Testing Framework
33 //
34 // This file implements a universal value printer that can print a
35 // value of any type T:
36 //
37 // void ::testing::internal::UniversalPrinter<T>::Print(value, ostream_ptr);
38 //
39 // It uses the << operator when possible, and prints the bytes in the
40 // object otherwise. A user can override its behavior for a class
41 // type Foo by defining either operator<<(::std::ostream&, const Foo&)
42 // or void PrintTo(const Foo&, ::std::ostream*) in the namespace that
43 // defines Foo.
44 
45 #include "gtest/gtest-printers.h"
46 #include <ctype.h>
47 #include <stdio.h>
48 #include <ostream> // NOLINT
49 #include <string>
51 
52 namespace testing {
53 
54 namespace {
55 
56 using ::std::ostream;
57 
58 // Prints a segment of bytes in the given object.
59 void PrintByteSegmentInObjectTo(const unsigned char* obj_bytes, size_t start,
60  size_t count, ostream* os) {
61  char text[5] = "";
62  for (size_t i = 0; i != count; i++) {
63  const size_t j = start + i;
64  if (i != 0) {
65  // Organizes the bytes into groups of 2 for easy parsing by
66  // human.
67  if ((j % 2) == 0)
68  *os << ' ';
69  else
70  *os << '-';
71  }
72  GTEST_SNPRINTF_(text, sizeof(text), "%02X", obj_bytes[j]);
73  *os << text;
74  }
75 }
76 
77 // Prints the bytes in the given value to the given ostream.
78 void PrintBytesInObjectToImpl(const unsigned char* obj_bytes, size_t count,
79  ostream* os) {
80  // Tells the user how big the object is.
81  *os << count << "-byte object <";
82 
83  const size_t kThreshold = 132;
84  const size_t kChunkSize = 64;
85  // If the object size is bigger than kThreshold, we'll have to omit
86  // some details by printing only the first and the last kChunkSize
87  // bytes.
88  // TODO(wan): let the user control the threshold using a flag.
89  if (count < kThreshold) {
90  PrintByteSegmentInObjectTo(obj_bytes, 0, count, os);
91  } else {
92  PrintByteSegmentInObjectTo(obj_bytes, 0, kChunkSize, os);
93  *os << " ... ";
94  // Rounds up to 2-byte boundary.
95  const size_t resume_pos = (count - kChunkSize + 1)/2*2;
96  PrintByteSegmentInObjectTo(obj_bytes, resume_pos, count - resume_pos, os);
97  }
98  *os << ">";
99 }
100 
101 } // namespace
102 
103 namespace internal2 {
104 
105 // Delegates to PrintBytesInObjectToImpl() to print the bytes in the
106 // given object. The delegation simplifies the implementation, which
107 // uses the << operator and thus is easier done outside of the
108 // ::testing::internal namespace, which contains a << operator that
109 // sometimes conflicts with the one in STL.
110 void PrintBytesInObjectTo(const unsigned char* obj_bytes, size_t count,
111  ostream* os) {
112  PrintBytesInObjectToImpl(obj_bytes, count, os);
113 }
114 
115 } // namespace internal2
116 
117 namespace internal {
118 
119 // Depending on the value of a char (or wchar_t), we print it in one
120 // of three formats:
121 // - as is if it's a printable ASCII (e.g. 'a', '2', ' '),
122 // - as a hexidecimal escape sequence (e.g. '\x7F'), or
123 // - as a special escape sequence (e.g. '\r', '\n').
128 };
129 
130 // Returns true if c is a printable ASCII character. We test the
131 // value of c directly instead of calling isprint(), which is buggy on
132 // Windows Mobile.
133 inline bool IsPrintableAscii(wchar_t c) {
134  return 0x20 <= c && c <= 0x7E;
135 }
136 
137 // Prints a wide or narrow char c as a character literal without the
138 // quotes, escaping it when necessary; returns how c was formatted.
139 // The template argument UnsignedChar is the unsigned version of Char,
140 // which is the type of c.
141 template <typename UnsignedChar, typename Char>
142 static CharFormat PrintAsCharLiteralTo(Char c, ostream* os) {
143  switch (static_cast<wchar_t>(c)) {
144  case L'\0':
145  *os << "\\0";
146  break;
147  case L'\'':
148  *os << "\\'";
149  break;
150  case L'\\':
151  *os << "\\\\";
152  break;
153  case L'\a':
154  *os << "\\a";
155  break;
156  case L'\b':
157  *os << "\\b";
158  break;
159  case L'\f':
160  *os << "\\f";
161  break;
162  case L'\n':
163  *os << "\\n";
164  break;
165  case L'\r':
166  *os << "\\r";
167  break;
168  case L'\t':
169  *os << "\\t";
170  break;
171  case L'\v':
172  *os << "\\v";
173  break;
174  default:
175  if (IsPrintableAscii(c)) {
176  *os << static_cast<char>(c);
177  return kAsIs;
178  } else {
179  *os << "\\x" + String::FormatHexInt(static_cast<UnsignedChar>(c));
180  return kHexEscape;
181  }
182  }
183  return kSpecialEscape;
184 }
185 
186 // Prints a wchar_t c as if it's part of a string literal, escaping it when
187 // necessary; returns how c was formatted.
188 static CharFormat PrintAsStringLiteralTo(wchar_t c, ostream* os) {
189  switch (c) {
190  case L'\'':
191  *os << "'";
192  return kAsIs;
193  case L'"':
194  *os << "\\\"";
195  return kSpecialEscape;
196  default:
197  return PrintAsCharLiteralTo<wchar_t>(c, os);
198  }
199 }
200 
201 // Prints a char c as if it's part of a string literal, escaping it when
202 // necessary; returns how c was formatted.
203 static CharFormat PrintAsStringLiteralTo(char c, ostream* os) {
204  return PrintAsStringLiteralTo(
205  static_cast<wchar_t>(static_cast<unsigned char>(c)), os);
206 }
207 
208 // Prints a wide or narrow character c and its code. '\0' is printed
209 // as "'\\0'", other unprintable characters are also properly escaped
210 // using the standard C++ escape sequence. The template argument
211 // UnsignedChar is the unsigned version of Char, which is the type of c.
212 template <typename UnsignedChar, typename Char>
213 void PrintCharAndCodeTo(Char c, ostream* os) {
214  // First, print c as a literal in the most readable form we can find.
215  *os << ((sizeof(c) > 1) ? "L'" : "'");
216  const CharFormat format = PrintAsCharLiteralTo<UnsignedChar>(c, os);
217  *os << "'";
218 
219  // To aid user debugging, we also print c's code in decimal, unless
220  // it's 0 (in which case c was printed as '\\0', making the code
221  // obvious).
222  if (c == 0)
223  return;
224  *os << " (" << static_cast<int>(c);
225 
226  // For more convenience, we print c's code again in hexidecimal,
227  // unless c was already printed in the form '\x##' or the code is in
228  // [1, 9].
229  if (format == kHexEscape || (1 <= c && c <= 9)) {
230  // Do nothing.
231  } else {
232  *os << ", 0x" << String::FormatHexInt(static_cast<UnsignedChar>(c));
233  }
234  *os << ")";
235 }
236 
237 void PrintTo(unsigned char c, ::std::ostream* os) {
238  PrintCharAndCodeTo<unsigned char>(c, os);
239 }
240 void PrintTo(signed char c, ::std::ostream* os) {
241  PrintCharAndCodeTo<unsigned char>(c, os);
242 }
243 
244 // Prints a wchar_t as a symbol if it is printable or as its internal
245 // code otherwise and also as its code. L'\0' is printed as "L'\\0'".
246 void PrintTo(wchar_t wc, ostream* os) {
247  PrintCharAndCodeTo<wchar_t>(wc, os);
248 }
249 
250 // Prints the given array of characters to the ostream. CharType must be either
251 // char or wchar_t.
252 // The array starts at begin, the length is len, it may include '\0' characters
253 // and may not be NUL-terminated.
254 template <typename CharType>
256  const CharType* begin, size_t len, ostream* os) {
257  const char* const kQuoteBegin = sizeof(CharType) == 1 ? "\"" : "L\"";
258  *os << kQuoteBegin;
259  bool is_previous_hex = false;
260  for (size_t index = 0; index < len; ++index) {
261  const CharType cur = begin[index];
262  if (is_previous_hex && IsXDigit(cur)) {
263  // Previous character is of '\x..' form and this character can be
264  // interpreted as another hexadecimal digit in its number. Break string to
265  // disambiguate.
266  *os << "\" " << kQuoteBegin;
267  }
268  is_previous_hex = PrintAsStringLiteralTo(cur, os) == kHexEscape;
269  }
270  *os << "\"";
271 }
272 
273 // Prints a (const) char/wchar_t array of 'len' elements, starting at address
274 // 'begin'. CharType must be either char or wchar_t.
275 template <typename CharType>
277  const CharType* begin, size_t len, ostream* os) {
278  // The code
279  // const char kFoo[] = "foo";
280  // generates an array of 4, not 3, elements, with the last one being '\0'.
281  //
282  // Therefore when printing a char array, we don't print the last element if
283  // it's '\0', such that the output matches the string literal as it's
284  // written in the source code.
285  if (len > 0 && begin[len - 1] == '\0') {
286  PrintCharsAsStringTo(begin, len - 1, os);
287  return;
288  }
289 
290  // If, however, the last element in the array is not '\0', e.g.
291  // const char kFoo[] = { 'f', 'o', 'o' };
292  // we must print the entire array. We also print a message to indicate
293  // that the array is not NUL-terminated.
294  PrintCharsAsStringTo(begin, len, os);
295  *os << " (no terminating NUL)";
296 }
297 
298 // Prints a (const) char array of 'len' elements, starting at address 'begin'.
299 void UniversalPrintArray(const char* begin, size_t len, ostream* os) {
300  UniversalPrintCharArray(begin, len, os);
301 }
302 
303 // Prints a (const) wchar_t array of 'len' elements, starting at address
304 // 'begin'.
305 void UniversalPrintArray(const wchar_t* begin, size_t len, ostream* os) {
306  UniversalPrintCharArray(begin, len, os);
307 }
308 
309 // Prints the given C string to the ostream.
310 void PrintTo(const char* s, ostream* os) {
311  if (s == NULL) {
312  *os << "NULL";
313  } else {
314  *os << ImplicitCast_<const void*>(s) << " pointing to ";
315  PrintCharsAsStringTo(s, strlen(s), os);
316  }
317 }
318 
319 // MSVC compiler can be configured to define whar_t as a typedef
320 // of unsigned short. Defining an overload for const wchar_t* in that case
321 // would cause pointers to unsigned shorts be printed as wide strings,
322 // possibly accessing more memory than intended and causing invalid
323 // memory accesses. MSVC defines _NATIVE_WCHAR_T_DEFINED symbol when
324 // wchar_t is implemented as a native type.
325 #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
326 // Prints the given wide C string to the ostream.
327 void PrintTo(const wchar_t* s, ostream* os) {
328  if (s == NULL) {
329  *os << "NULL";
330  } else {
331  *os << ImplicitCast_<const void*>(s) << " pointing to ";
332  PrintCharsAsStringTo(s, wcslen(s), os);
333  }
334 }
335 #endif // wchar_t is native
336 
337 // Prints a ::string object.
338 #if GTEST_HAS_GLOBAL_STRING
339 void PrintStringTo(const ::string& s, ostream* os) {
340  PrintCharsAsStringTo(s.data(), s.size(), os);
341 }
342 #endif // GTEST_HAS_GLOBAL_STRING
343 
344 void PrintStringTo(const ::std::string& s, ostream* os) {
345  PrintCharsAsStringTo(s.data(), s.size(), os);
346 }
347 
348 // Prints a ::wstring object.
349 #if GTEST_HAS_GLOBAL_WSTRING
350 void PrintWideStringTo(const ::wstring& s, ostream* os) {
351  PrintCharsAsStringTo(s.data(), s.size(), os);
352 }
353 #endif // GTEST_HAS_GLOBAL_WSTRING
354 
355 #if GTEST_HAS_STD_WSTRING
356 void PrintWideStringTo(const ::std::wstring& s, ostream* os) {
357  PrintCharsAsStringTo(s.data(), s.size(), os);
358 }
359 #endif // GTEST_HAS_STD_WSTRING
360 
361 } // namespace internal
362 
363 } // namespace testing
testing::internal::PrintCharsAsStringTo
static void PrintCharsAsStringTo(const CharType *begin, size_t len, ostream *os)
Definition: gtest-printers.cc:255
testing
Definition: gtest-death-test.h:43
testing::internal::UniversalPrintCharArray
static void UniversalPrintCharArray(const CharType *begin, size_t len, ostream *os)
Definition: gtest-printers.cc:276
testing::internal::IsXDigit
bool IsXDigit(char ch)
Definition: gtest-port.h:1680
testing::internal::PrintStringTo
GTEST_API_ void PrintStringTo(const ::std::string &s, ::std::ostream *os)
testing::internal::PrintCharAndCodeTo
void PrintCharAndCodeTo(Char c, ostream *os)
Definition: gtest-printers.cc:213
testing::internal::PrintAsStringLiteralTo
static CharFormat PrintAsStringLiteralTo(wchar_t c, ostream *os)
Definition: gtest-printers.cc:188
testing::internal::String::FormatHexInt
static std::string FormatHexInt(int value)
Definition: gtest.cc:1646
testing::internal2::PrintBytesInObjectTo
GTEST_API_ void PrintBytesInObjectTo(const unsigned char *obj_bytes, size_t count, ::std::ostream *os)
GTEST_SNPRINTF_
#define GTEST_SNPRINTF_
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testing::internal::wstring
::std::wstring wstring
Definition: gtest-port.h:881
testing::internal::string
::std::string string
Definition: gtest-port.h:875
testing::internal::CharFormat
CharFormat
Definition: gtest-printers.cc:124
gtest-port.h
testing::internal::UniversalPrintArray
void UniversalPrintArray(const T *begin, size_t len, ::std::ostream *os)
Definition: gtest-printers.h:614
testing::internal::kHexEscape
@ kHexEscape
Definition: gtest-printers.cc:126
testing::internal::PrintAsCharLiteralTo
static CharFormat PrintAsCharLiteralTo(Char c, ostream *os)
Definition: gtest-printers.cc:142
testing::internal::IsPrintableAscii
bool IsPrintableAscii(wchar_t c)
Definition: gtest-printers.cc:133
testing::internal::kSpecialEscape
@ kSpecialEscape
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gtest-printers.h
testing::internal::kAsIs
@ kAsIs
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