125 lines
3.1 KiB
C++
125 lines
3.1 KiB
C++
// Copyright (C) 2009, International Business Machines
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// Corporation and others. All Rights Reserved.
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//
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// Copyright 2001 and onwards Google Inc.
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// Author: Sanjay Ghemawat
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//
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#ifndef __STRINGPIECE_H__
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#define __STRINGPIECE_H__
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/**
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* \file
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* \brief C++ API: StringPiece: Read-only byte string wrapper class.
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*/
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#include "unicode/utypes.h"
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#include "unicode/uobject.h"
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#include "unicode/std_string.h"
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// Arghh! I wish C++ literals were "string".
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U_NAMESPACE_BEGIN
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///
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/// A string-like object that points to a sized piece of memory.
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///
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/// Functions or methods may use const StringPiece& parameters to accept either
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/// a "const char*" or a "string" value that will be implicitly converted to
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/// a StringPiece.
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///
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/// Systematic usage of StringPiece is encouraged as it will reduce unnecessary
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/// conversions from "const char*" to "string" and back again.
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///
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///
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///
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/// @draft ICU 4.2
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///
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class U_COMMON_API StringPiece : public UMemory {
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private:
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const char* ptr_;
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int32_t length_;
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public:
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/// We provide non-explicit singleton constructors so users can pass
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/// in a "const char*" or a "string" wherever a "StringPiece" is
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/// expected.
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/// @draft ICU 4.2
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StringPiece() : ptr_(NULL), length_(0) { }
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/**
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* @draft ICU 4.2
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*/
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StringPiece(const char* str);
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#if U_HAVE_STD_STRING
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/**
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* @draft ICU 4.2
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*/
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StringPiece(const U_STD_NSQ string& str)
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: ptr_(str.data()), length_(static_cast<int32_t>(str.size())) { }
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#endif
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/**
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* @draft ICU 4.2
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*/
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StringPiece(const char* offset, int32_t len) : ptr_(offset), length_(len) { }
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/// Substring of another StringPiece.
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/// pos must be non-negative and <= x.length().
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/// @draft ICU 4.2
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StringPiece(const StringPiece& x, int32_t pos);
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/// Substring of another StringPiece.
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/// pos must be non-negative and <= x.length().
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/// len must be non-negative and will be pinned to at most x.length() - pos.
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/// @draft ICU 4.2
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StringPiece(const StringPiece& x, int32_t pos, int32_t len);
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/// data() may return a pointer to a buffer with embedded NULs, and the
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/// returned buffer may or may not be null terminated. Therefore it is
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/// typically a mistake to pass data() to a routine that expects a NUL
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/// terminated string.
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/// @draft ICU 4.2
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const char* data() const { return ptr_; }
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/** @draft ICU 4.2 */
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int32_t size() const { return length_; }
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/** @draft ICU 4.2 */
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int32_t length() const { return length_; }
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/** @draft ICU 4.2 */
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UBool empty() const { return length_ == 0; }
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/** @draft ICU 4.2 */
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void clear() { ptr_ = NULL; length_ = 0; }
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/** @draft ICU 4.2 */
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void remove_prefix(int32_t n) {
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if (n >= 0) {
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if (n > length_) {
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n = length_;
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}
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ptr_ += n;
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length_ -= n;
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}
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}
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/** @draft ICU 4.2 */
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void remove_suffix(int32_t n) {
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if (n >= 0) {
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if (n <= length_) {
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length_ -= n;
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} else {
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length_ = 0;
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}
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}
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}
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/** @draft ICU 4.2 */
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static const int32_t npos = 0x7fffffff;
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/** @draft ICU 4.2 */
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StringPiece substr(int32_t pos, int32_t n = npos) const {
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return StringPiece(*this, pos, n);
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}
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};
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U_NAMESPACE_END
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#endif // __STRINGPIECE_H__
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