// Copyright (C) 2010, International Business Machines // Corporation and others. All Rights Reserved. // // Copyright 2001 and onwards Google Inc. // Author: Sanjay Ghemawat // This code is a contribution of Google code, and the style used here is // a compromise between the original Google code and the ICU coding guidelines. // For example, data types are ICU-ified (size_t,int->int32_t), // and API comments doxygen-ified, but function names and behavior are // as in the original, if possible. // Assertion-style error handling, not available in ICU, was changed to // parameter "pinning" similar to UnicodeString. // // In addition, this is only a partial port of the original Google code, // limited to what was needed so far. The (nearly) complete original code // is in the ICU svn repository at icuhtml/trunk/design/strings/contrib // (see ICU ticket 6765, r25517). #ifndef __STRINGPIECE_H__ #define __STRINGPIECE_H__ /** * \file * \brief C++ API: StringPiece: Read-only byte string wrapper class. */ #include "unicode/utypes.h" #include "unicode/uobject.h" #include "unicode/std_string.h" // Arghh! I wish C++ literals were "string". U_NAMESPACE_BEGIN /** * A string-like object that points to a sized piece of memory. * * We provide non-explicit singleton constructors so users can pass * in a "const char*" or a "string" wherever a "StringPiece" is * expected. * * Functions or methods may use const StringPiece& parameters to accept either * a "const char*" or a "string" value that will be implicitly converted to * a StringPiece. * * Systematic usage of StringPiece is encouraged as it will reduce unnecessary * conversions from "const char*" to "string" and back again. * * @stable ICU 4.2 */ class U_COMMON_API StringPiece : public UMemory { private: const char* ptr_; int32_t length_; public: /** * Default constructor, creates an empty StringPiece. * @stable ICU 4.2 */ StringPiece() : ptr_(NULL), length_(0) { } /** * Constructs from a NUL-terminated const char * pointer. * @param str a NUL-terminated const char * pointer * @stable ICU 4.2 */ StringPiece(const char* str); #if U_HAVE_STD_STRING /** * Constructs from a std::string. * @stable ICU 4.2 */ StringPiece(const U_STD_NSQ string& str) : ptr_(str.data()), length_(static_cast<int32_t>(str.size())) { } #endif /** * Constructs from a const char * pointer and a specified length. * @param offset a const char * pointer (need not be terminated) * @param len the length of the string; must be non-negative * @stable ICU 4.2 */ StringPiece(const char* offset, int32_t len) : ptr_(offset), length_(len) { } /** * Substring of another StringPiece. * @param x the other StringPiece * @param pos start position in x; must be non-negative and <= x.length(). * @stable ICU 4.2 */ StringPiece(const StringPiece& x, int32_t pos); /** * Substring of another StringPiece. * @param x the other StringPiece * @param pos start position in x; must be non-negative and <= x.length(). * @param len length of the substring; * must be non-negative and will be pinned to at most x.length() - pos. * @stable ICU 4.2 */ StringPiece(const StringPiece& x, int32_t pos, int32_t len); /** * Returns the string pointer. May be NULL if it is empty. * * data() may return a pointer to a buffer with embedded NULs, and the * returned buffer may or may not be null terminated. Therefore it is * typically a mistake to pass data() to a routine that expects a NUL * terminated string. * @return the string pointer * @stable ICU 4.2 */ const char* data() const { return ptr_; } /** * Returns the string length. Same as length(). * @return the string length * @stable ICU 4.2 */ int32_t size() const { return length_; } /** * Returns the string length. Same as size(). * @return the string length * @stable ICU 4.2 */ int32_t length() const { return length_; } /** * Returns whether the string is empty. * @return TRUE if the string is empty * @stable ICU 4.2 */ UBool empty() const { return length_ == 0; } /** * Sets to an empty string. * @stable ICU 4.2 */ void clear() { ptr_ = NULL; length_ = 0; } /** * Reset the stringpiece to refer to new data. * @param data pointer the new string data. Need not be nul terminated. * @param len the length of the new data * @internal */ void set(const char* data, int32_t len) { ptr_ = data; length_ = len; } /** * Reset the stringpiece to refer to new data. * @param str a pointer to a NUL-terminated string. * @internal */ void set(const char* str); /** * Removes the first n string units. * @param n prefix length, must be non-negative and <=length() * @stable ICU 4.2 */ void remove_prefix(int32_t n) { if (n >= 0) { if (n > length_) { n = length_; } ptr_ += n; length_ -= n; } } /** * Removes the last n string units. * @param n suffix length, must be non-negative and <=length() * @stable ICU 4.2 */ void remove_suffix(int32_t n) { if (n >= 0) { if (n <= length_) { length_ -= n; } else { length_ = 0; } } } /** * Maximum integer, used as a default value for substring methods. * @stable ICU 4.2 */ static const int32_t npos = 0x7fffffff; /** * Returns a substring of this StringPiece. * @param pos start position; must be non-negative and <= length(). * @param len length of the substring; * must be non-negative and will be pinned to at most length() - pos. * @return the substring StringPiece * @stable ICU 4.2 */ StringPiece substr(int32_t pos, int32_t len = npos) const { return StringPiece(*this, pos, len); } }; /** * Global operator == for StringPiece * @param x The first StringPiece to compare. * @param y The second StringPiece to compare. * @return TRUE if the string data is equal * @internal */ U_EXPORT UBool U_EXPORT2 operator==(const StringPiece& x, const StringPiece& y); /** * Global operator != for StringPiece * @param x The first StringPiece to compare. * @param y The second StringPiece to compare. * @return TRUE if the string data is not equal * @internal */ inline UBool operator!=(const StringPiece& x, const StringPiece& y) { return !(x == y); } U_NAMESPACE_END #endif // __STRINGPIECE_H__