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30 
31 // Author: kenton@google.com (Kenton Varda)
32 // from google3/strings/substitute.h
33 
34 #include <string>
35 #include <google/protobuf/stubs/common.h>
36 #include <google/protobuf/stubs/strutil.h>
37 
38 #ifndef GOOGLE_PROTOBUF_STUBS_SUBSTITUTE_H_
39 #define GOOGLE_PROTOBUF_STUBS_SUBSTITUTE_H_
40 
41 namespace google {
42 namespace protobuf {
43 namespace strings {
44 
45 // ----------------------------------------------------------------------
46 // strings::Substitute()
47 // strings::SubstituteAndAppend()
48 //   Kind of like StringPrintf, but different.
49 //
50 //   Example:
51 //     string GetMessage(string first_name, string last_name, int age) {
52 //       return strings::Substitute("My name is $0 $1 and I am $2 years old.",
53 //                                  first_name, last_name, age);
54 //     }
55 //
56 //   Differences from StringPrintf:
57 //   * The format string does not identify the types of arguments.
58 //     Instead, the magic of C++ deals with this for us.  See below
59 //     for a list of accepted types.
60 //   * Substitutions in the format string are identified by a '$'
61 //     followed by a digit.  So, you can use arguments out-of-order and
62 //     use the same argument multiple times.
63 //   * It's much faster than StringPrintf.
64 //
65 //   Supported types:
66 //   * Strings (const char*, const string&)
67 //     * Note that this means you do not have to add .c_str() to all of
68 //       your strings.  In fact, you shouldn't; it will be slower.
69 //   * int32, int64, uint32, uint64:  Formatted using SimpleItoa().
70 //   * float, double:  Formatted using SimpleFtoa() and SimpleDtoa().
71 //   * bool:  Printed as "true" or "false".
72 //
73 //   SubstituteAndAppend() is like Substitute() but appends the result to
74 //   *output.  Example:
75 //
76 //     string str;
77 //     strings::SubstituteAndAppend(&str,
78 //                                  "My name is $0 $1 and I am $2 years old.",
79 //                                  first_name, last_name, age);
80 //
81 //   Substitute() is significantly faster than StringPrintf().  For very
82 //   large strings, it may be orders of magnitude faster.
83 // ----------------------------------------------------------------------
84 
85 namespace internal {  // Implementation details.
86 
87 class SubstituteArg {
88  public:
SubstituteArg(const char * value)89   inline SubstituteArg(const char* value)
90     : text_(value), size_(strlen(text_)) {}
SubstituteArg(const string & value)91   inline SubstituteArg(const string& value)
92     : text_(value.data()), size_(value.size()) {}
93 
94   // Indicates that no argument was given.
SubstituteArg()95   inline explicit SubstituteArg()
96     : text_(NULL), size_(-1) {}
97 
98   // Primitives
99   // We don't overload for signed and unsigned char because if people are
100   // explicitly declaring their chars as signed or unsigned then they are
101   // probably actually using them as 8-bit integers and would probably
102   // prefer an integer representation.  But, we don't really know.  So, we
103   // make the caller decide what to do.
SubstituteArg(char value)104   inline SubstituteArg(char value)
105     : text_(scratch_), size_(1) { scratch_[0] = value; }
SubstituteArg(short value)106   inline SubstituteArg(short value)
107     : text_(FastInt32ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(unsigned short value)108   inline SubstituteArg(unsigned short value)
109     : text_(FastUInt32ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(int value)110   inline SubstituteArg(int value)
111     : text_(FastInt32ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(unsigned int value)112   inline SubstituteArg(unsigned int value)
113     : text_(FastUInt32ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(long value)114   inline SubstituteArg(long value)
115     : text_(FastLongToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(unsigned long value)116   inline SubstituteArg(unsigned long value)
117     : text_(FastULongToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(long long value)118   inline SubstituteArg(long long value)
119     : text_(FastInt64ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(unsigned long long value)120   inline SubstituteArg(unsigned long long value)
121     : text_(FastUInt64ToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(float value)122   inline SubstituteArg(float value)
123     : text_(FloatToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(double value)124   inline SubstituteArg(double value)
125     : text_(DoubleToBuffer(value, scratch_)), size_(strlen(text_)) {}
SubstituteArg(bool value)126   inline SubstituteArg(bool value)
127     : text_(value ? "true" : "false"), size_(strlen(text_)) {}
128 
data()129   inline const char* data() const { return text_; }
size()130   inline int size() const { return size_; }
131 
132  private:
133   const char* text_;
134   int size_;
135   char scratch_[kFastToBufferSize];
136 };
137 
138 }  // namespace internal
139 
140 LIBPROTOBUF_EXPORT string Substitute(
141   const char* format,
142   const internal::SubstituteArg& arg0 = internal::SubstituteArg(),
143   const internal::SubstituteArg& arg1 = internal::SubstituteArg(),
144   const internal::SubstituteArg& arg2 = internal::SubstituteArg(),
145   const internal::SubstituteArg& arg3 = internal::SubstituteArg(),
146   const internal::SubstituteArg& arg4 = internal::SubstituteArg(),
147   const internal::SubstituteArg& arg5 = internal::SubstituteArg(),
148   const internal::SubstituteArg& arg6 = internal::SubstituteArg(),
149   const internal::SubstituteArg& arg7 = internal::SubstituteArg(),
150   const internal::SubstituteArg& arg8 = internal::SubstituteArg(),
151   const internal::SubstituteArg& arg9 = internal::SubstituteArg());
152 
153 LIBPROTOBUF_EXPORT void SubstituteAndAppend(
154   string* output, const char* format,
155   const internal::SubstituteArg& arg0 = internal::SubstituteArg(),
156   const internal::SubstituteArg& arg1 = internal::SubstituteArg(),
157   const internal::SubstituteArg& arg2 = internal::SubstituteArg(),
158   const internal::SubstituteArg& arg3 = internal::SubstituteArg(),
159   const internal::SubstituteArg& arg4 = internal::SubstituteArg(),
160   const internal::SubstituteArg& arg5 = internal::SubstituteArg(),
161   const internal::SubstituteArg& arg6 = internal::SubstituteArg(),
162   const internal::SubstituteArg& arg7 = internal::SubstituteArg(),
163   const internal::SubstituteArg& arg8 = internal::SubstituteArg(),
164   const internal::SubstituteArg& arg9 = internal::SubstituteArg());
165 
166 }  // namespace strings
167 }  // namespace protobuf
168 }  // namespace google
169 
170 #endif // GOOGLE_PROTOBUF_STUBS_SUBSTITUTE_H_
171