ICU 60.2  60.2
bytestream.h
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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 // Copyright (C) 2009-2012, International Business Machines
4 // Corporation and others. All Rights Reserved.
5 //
6 // Copyright 2007 Google Inc. All Rights Reserved.
7 // Author: sanjay@google.com (Sanjay Ghemawat)
8 //
9 // Abstract interface that consumes a sequence of bytes (ByteSink).
10 //
11 // Used so that we can write a single piece of code that can operate
12 // on a variety of output string types.
13 //
14 // Various implementations of this interface are provided:
15 // ByteSink:
16 // CheckedArrayByteSink Write to a flat array, with bounds checking
17 // StringByteSink Write to an STL string
18 
19 // This code is a contribution of Google code, and the style used here is
20 // a compromise between the original Google code and the ICU coding guidelines.
21 // For example, data types are ICU-ified (size_t,int->int32_t),
22 // and API comments doxygen-ified, but function names and behavior are
23 // as in the original, if possible.
24 // Assertion-style error handling, not available in ICU, was changed to
25 // parameter "pinning" similar to UnicodeString.
26 //
27 // In addition, this is only a partial port of the original Google code,
28 // limited to what was needed so far. The (nearly) complete original code
29 // is in the ICU svn repository at icuhtml/trunk/design/strings/contrib
30 // (see ICU ticket 6765, r25517).
31 
32 #ifndef __BYTESTREAM_H__
33 #define __BYTESTREAM_H__
34 
40 #include "unicode/utypes.h"
41 #include "unicode/uobject.h"
42 #include "unicode/std_string.h"
43 
45 
50 class U_COMMON_API ByteSink : public UMemory {
51 public:
56  ByteSink() { }
61  virtual ~ByteSink();
62 
69  virtual void Append(const char* bytes, int32_t n) = 0;
70 
113  virtual char* GetAppendBuffer(int32_t min_capacity,
114  int32_t desired_capacity_hint,
115  char* scratch, int32_t scratch_capacity,
116  int32_t* result_capacity);
117 
126  virtual void Flush();
127 
128 private:
129  ByteSink(const ByteSink &) = delete;
130  ByteSink &operator=(const ByteSink &) = delete;
131 };
132 
133 // -------------------------------------------------------------
134 // Some standard implementations
135 
146 public:
153  CheckedArrayByteSink(char* outbuf, int32_t capacity);
158  virtual ~CheckedArrayByteSink();
167  virtual CheckedArrayByteSink& Reset();
174  virtual void Append(const char* bytes, int32_t n);
189  virtual char* GetAppendBuffer(int32_t min_capacity,
190  int32_t desired_capacity_hint,
191  char* scratch, int32_t scratch_capacity,
192  int32_t* result_capacity);
198  int32_t NumberOfBytesWritten() const { return size_; }
205  UBool Overflowed() const { return overflowed_; }
213  int32_t NumberOfBytesAppended() const { return appended_; }
214 private:
215  char* outbuf_;
216  const int32_t capacity_;
217  int32_t size_;
218  int32_t appended_;
219  UBool overflowed_;
220 
221  CheckedArrayByteSink() = delete;
222  CheckedArrayByteSink(const CheckedArrayByteSink &) = delete;
223  CheckedArrayByteSink &operator=(const CheckedArrayByteSink &) = delete;
224 };
225 
231 template<typename StringClass>
232 class StringByteSink : public ByteSink {
233  public:
239  StringByteSink(StringClass* dest) : dest_(dest) { }
240 #ifndef U_HIDE_DRAFT_API
241 
248  StringByteSink(StringClass* dest, int32_t initialAppendCapacity) : dest_(dest) {
249  if (initialAppendCapacity > 0 &&
250  (uint32_t)initialAppendCapacity > (dest->capacity() - dest->length())) {
251  dest->reserve(dest->length() + initialAppendCapacity);
252  }
253  }
254 #endif // U_HIDE_DRAFT_API
255 
261  virtual void Append(const char* data, int32_t n) { dest_->append(data, n); }
262  private:
263  StringClass* dest_;
264 
265  StringByteSink() = delete;
266  StringByteSink(const StringByteSink &) = delete;
267  StringByteSink &operator=(const StringByteSink &) = delete;
268 };
269 
271 
272 #endif // __BYTESTREAM_H__
virtual char * GetAppendBuffer(int32_t min_capacity, int32_t desired_capacity_hint, char *scratch, int32_t scratch_capacity, int32_t *result_capacity)
Returns a writable buffer for appending and writes the buffer&#39;s capacity to *result_capacity.
StringByteSink(StringClass *dest)
Constructs a ByteSink that will append bytes to the dest string.
Definition: bytestream.h:239
int32_t NumberOfBytesWritten() const
Returns the number of bytes actually written to the sink.
Definition: bytestream.h:198
virtual void Append(const char *data, int32_t n)
Append "bytes[0,n-1]" to this.
Definition: bytestream.h:261
UBool Overflowed() const
Returns true if any bytes were discarded, i.e., if there was an attempt to write more than &#39;capacity&#39;...
Definition: bytestream.h:205
ByteSink()
Default constructor.
Definition: bytestream.h:56
A ByteSink can be filled with bytes.
Definition: bytestream.h:50
virtual void Append(const char *bytes, int32_t n)=0
Append "bytes[0,n-1]" to this.
Implementation of ByteSink that writes to a flat byte array, with bounds-checking: This sink will not...
Definition: bytestream.h:145
#define U_NAMESPACE_BEGIN
This is used to begin a declaration of a public ICU C++ API.
Definition: uversion.h:131
StringByteSink(StringClass *dest, int32_t initialAppendCapacity)
Constructs a ByteSink that reserves append capacity and will append bytes to the dest string...
Definition: bytestream.h:248
C++ API: Central ICU header for including the C++ standard <string> header and for related definition...
C++ API: Common ICU base class UObject.
#define U_NAMESPACE_END
This is used to end a declaration of a public ICU C++ API.
Definition: uversion.h:132
int32_t NumberOfBytesAppended() const
Returns the number of bytes appended to the sink.
Definition: bytestream.h:213
Basic definitions for ICU, for both C and C++ APIs.
Implementation of ByteSink that writes to a "string".
Definition: bytestream.h:232
#define U_COMMON_API
Set to export library symbols from inside the common library, and to import them from outside...
Definition: utypes.h:359
UMemory is the common ICU base class.
Definition: uobject.h:112
int8_t UBool
The ICU boolean type.
Definition: umachine.h:236