From e96ff30120a3834f7d1e31e43e591bf7cfbd731f Mon Sep 17 00:00:00 2001 From: Feng Xiao Date: Mon, 15 Jun 2015 18:21:48 -0700 Subject: Down-integrate from internal code base. [ci skip] Change-Id: I9391c09640e0b0b2b21c45a97a1fc91814d95c5d --- src/google/protobuf/stubs/stringpiece.h | 437 ++++++++++++++++++++++++++++++++ 1 file changed, 437 insertions(+) create mode 100644 src/google/protobuf/stubs/stringpiece.h (limited to 'src/google/protobuf/stubs/stringpiece.h') diff --git a/src/google/protobuf/stubs/stringpiece.h b/src/google/protobuf/stubs/stringpiece.h new file mode 100644 index 00000000..5d4d5fe4 --- /dev/null +++ b/src/google/protobuf/stubs/stringpiece.h @@ -0,0 +1,437 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// A StringPiece points to part or all of a string, Cord, double-quoted string +// literal, or other string-like object. A StringPiece does *not* own the +// string to which it points. A StringPiece is not null-terminated. +// +// You can use StringPiece as a function or method parameter. A StringPiece +// parameter can receive a double-quoted string literal argument, a "const +// char*" argument, a string argument, or a StringPiece argument with no data +// copying. Systematic use of StringPiece for arguments reduces data +// copies and strlen() calls. +// +// Prefer passing StringPieces by value: +// void MyFunction(StringPiece arg); +// If circumstances require, you may also pass by const reference: +// void MyFunction(const StringPiece& arg); // not preferred +// Both of these have the same lifetime semantics. Passing by value +// generates slightly smaller code. For more discussion, see the thread +// go/stringpiecebyvalue on c-users. +// +// StringPiece is also suitable for local variables if you know that +// the lifetime of the underlying object is longer than the lifetime +// of your StringPiece variable. +// +// Beware of binding a StringPiece to a temporary: +// StringPiece sp = obj.MethodReturningString(); // BAD: lifetime problem +// +// This code is okay: +// string str = obj.MethodReturningString(); // str owns its contents +// StringPiece sp(str); // GOOD, because str outlives sp +// +// StringPiece is sometimes a poor choice for a return value and usually a poor +// choice for a data member. If you do use a StringPiece this way, it is your +// responsibility to ensure that the object pointed to by the StringPiece +// outlives the StringPiece. +// +// A StringPiece may represent just part of a string; thus the name "Piece". +// For example, when splitting a string, vector is a natural data +// type for the output. For another example, a Cord is a non-contiguous, +// potentially very long string-like object. The Cord class has an interface +// that iteratively provides StringPiece objects that point to the +// successive pieces of a Cord object. +// +// A StringPiece is not null-terminated. If you write code that scans a +// StringPiece, you must check its length before reading any characters. +// Common idioms that work on null-terminated strings do not work on +// StringPiece objects. +// +// There are several ways to create a null StringPiece: +// StringPiece() +// StringPiece(NULL) +// StringPiece(NULL, 0) +// For all of the above, sp.data() == NULL, sp.length() == 0, +// and sp.empty() == true. Also, if you create a StringPiece with +// a non-NULL pointer then sp.data() != NULL. Once created, +// sp.data() will stay either NULL or not-NULL, except if you call +// sp.clear() or sp.set(). +// +// Thus, you can use StringPiece(NULL) to signal an out-of-band value +// that is different from other StringPiece values. This is similar +// to the way that const char* p1 = NULL; is different from +// const char* p2 = "";. +// +// There are many ways to create an empty StringPiece: +// StringPiece() +// StringPiece(NULL) +// StringPiece(NULL, 0) +// StringPiece("") +// StringPiece("", 0) +// StringPiece("abcdef", 0) +// StringPiece("abcdef"+6, 0) +// For all of the above, sp.length() will be 0 and sp.empty() will be true. +// For some empty StringPiece values, sp.data() will be NULL. +// For some empty StringPiece values, sp.data() will not be NULL. +// +// Be careful not to confuse: null StringPiece and empty StringPiece. +// The set of empty StringPieces properly includes the set of null StringPieces. +// That is, every null StringPiece is an empty StringPiece, +// but some non-null StringPieces are empty Stringpieces too. +// +// All empty StringPiece values compare equal to each other. +// Even a null StringPieces compares equal to a non-null empty StringPiece: +// StringPiece() == StringPiece("", 0) +// StringPiece(NULL) == StringPiece("abc", 0) +// StringPiece(NULL, 0) == StringPiece("abcdef"+6, 0) +// +// Look carefully at this example: +// StringPiece("") == NULL +// True or false? TRUE, because StringPiece::operator== converts +// the right-hand side from NULL to StringPiece(NULL), +// and then compares two zero-length spans of characters. +// However, we are working to make this example produce a compile error. +// +// Suppose you want to write: +// bool TestWhat?(StringPiece sp) { return sp == NULL; } // BAD +// Do not do that. Write one of these instead: +// bool TestNull(StringPiece sp) { return sp.data() == NULL; } +// bool TestEmpty(StringPiece sp) { return sp.empty(); } +// The intent of TestWhat? is unclear. Did you mean TestNull or TestEmpty? +// Right now, TestWhat? behaves likes TestEmpty. +// We are working to make TestWhat? produce a compile error. +// TestNull is good to test for an out-of-band signal. +// TestEmpty is good to test for an empty StringPiece. +// +// Caveats (again): +// (1) The lifetime of the pointed-to string (or piece of a string) +// must be longer than the lifetime of the StringPiece. +// (2) There may or may not be a '\0' character after the end of +// StringPiece data. +// (3) A null StringPiece is empty. +// An empty StringPiece may or may not be a null StringPiece. + +#ifndef GOOGLE_PROTOBUF_STUBS_STRINGPIECE_H_ +#define GOOGLE_PROTOBUF_STUBS_STRINGPIECE_H_ + +#include +#include +#include +#include +#include +#include + +#include + +namespace google { +namespace protobuf { +// StringPiece has *two* size types. +// StringPiece::size_type +// is unsigned +// is 32 bits in LP32, 64 bits in LP64, 64 bits in LLP64 +// no future changes intended +// stringpiece_ssize_type +// is signed +// is 32 bits in LP32, 64 bits in LP64, 64 bits in LLP64 +// future changes intended: http://go/64BitStringPiece +// +typedef string::difference_type stringpiece_ssize_type; + +// STRINGPIECE_CHECK_SIZE protects us from 32-bit overflows. +// TODO(mec): delete this after stringpiece_ssize_type goes 64 bit. +#if !defined(NDEBUG) +#define STRINGPIECE_CHECK_SIZE 1 +#elif defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 +#define STRINGPIECE_CHECK_SIZE 1 +#else +#define STRINGPIECE_CHECK_SIZE 0 +#endif + +class StringPiece { + private: + const char* ptr_; + stringpiece_ssize_type length_; + + // Prevent overflow in debug mode or fortified mode. + // sizeof(stringpiece_ssize_type) may be smaller than sizeof(size_t). + static stringpiece_ssize_type CheckedSsizeTFromSizeT(size_t size) { +#if STRINGPIECE_CHECK_SIZE > 0 + if (size > static_cast( + std::numeric_limits::max())) { + // Some people grep for this message in logs + // so take care if you ever change it. + LogFatalSizeTooBig(size, "size_t to int conversion"); + } +#endif + return static_cast(size); + } + + // Out-of-line error path. + static void LogFatalSizeTooBig(size_t size, const char* details); + + public: + // We provide non-explicit singleton constructors so users can pass + // in a "const char*" or a "string" wherever a "StringPiece" is + // expected. + // + // Style guide exception granted: + // http://goto/style-guide-exception-20978288 + StringPiece() : ptr_(NULL), length_(0) {} + + StringPiece(const char* str) // NOLINT(runtime/explicit) + : ptr_(str), length_(0) { + if (str != NULL) { + length_ = CheckedSsizeTFromSizeT(strlen(str)); + } + } + + template + StringPiece( // NOLINT(runtime/explicit) + const std::basic_string, Allocator>& str) + : ptr_(str.data()), length_(0) { + length_ = CheckedSsizeTFromSizeT(str.size()); + } +#if defined(HAS_GLOBAL_STRING) + template + StringPiece( // NOLINT(runtime/explicit) + const basic_string, Allocator>& str) + : ptr_(str.data()), length_(0) { + length_ = CheckedSsizeTFromSizeT(str.size()); + } +#endif + + StringPiece(const char* offset, stringpiece_ssize_type len) + : ptr_(offset), length_(len) { + assert(len >= 0); + } + + // Substring of another StringPiece. + // pos must be non-negative and <= x.length(). + StringPiece(StringPiece x, stringpiece_ssize_type pos); + // Substring of another StringPiece. + // pos must be non-negative and <= x.length(). + // len must be non-negative and will be pinned to at most x.length() - pos. + StringPiece(StringPiece x, + stringpiece_ssize_type pos, + stringpiece_ssize_type len); + + // 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. + const char* data() const { return ptr_; } + stringpiece_ssize_type size() const { return length_; } + stringpiece_ssize_type length() const { return length_; } + bool empty() const { return length_ == 0; } + + void clear() { + ptr_ = NULL; + length_ = 0; + } + + void set(const char* data, stringpiece_ssize_type len) { + assert(len >= 0); + ptr_ = data; + length_ = len; + } + + void set(const char* str) { + ptr_ = str; + if (str != NULL) + length_ = CheckedSsizeTFromSizeT(strlen(str)); + else + length_ = 0; + } + + void set(const void* data, stringpiece_ssize_type len) { + ptr_ = reinterpret_cast(data); + length_ = len; + } + + char operator[](stringpiece_ssize_type i) const { + assert(0 <= i); + assert(i < length_); + return ptr_[i]; + } + + void remove_prefix(stringpiece_ssize_type n) { + assert(length_ >= n); + ptr_ += n; + length_ -= n; + } + + void remove_suffix(stringpiece_ssize_type n) { + assert(length_ >= n); + length_ -= n; + } + + // returns {-1, 0, 1} + int compare(StringPiece x) const { + const stringpiece_ssize_type min_size = + length_ < x.length_ ? length_ : x.length_; + int r = memcmp(ptr_, x.ptr_, min_size); + if (r < 0) return -1; + if (r > 0) return 1; + if (length_ < x.length_) return -1; + if (length_ > x.length_) return 1; + return 0; + } + + string as_string() const { + return ToString(); + } + // We also define ToString() here, since many other string-like + // interfaces name the routine that converts to a C++ string + // "ToString", and it's confusing to have the method that does that + // for a StringPiece be called "as_string()". We also leave the + // "as_string()" method defined here for existing code. + string ToString() const { + if (ptr_ == NULL) return string(); + return string(data(), size()); + } + + operator string() const { + return ToString(); + } + + void CopyToString(string* target) const; + void AppendToString(string* target) const; + + bool starts_with(StringPiece x) const { + return (length_ >= x.length_) && (memcmp(ptr_, x.ptr_, x.length_) == 0); + } + + bool ends_with(StringPiece x) const { + return ((length_ >= x.length_) && + (memcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0)); + } + + // Checks whether StringPiece starts with x and if so advances the beginning + // of it to past the match. It's basically a shortcut for starts_with + // followed by remove_prefix. + bool Consume(StringPiece x); + // Like above but for the end of the string. + bool ConsumeFromEnd(StringPiece x); + + // standard STL container boilerplate + typedef char value_type; + typedef const char* pointer; + typedef const char& reference; + typedef const char& const_reference; + typedef size_t size_type; + typedef ptrdiff_t difference_type; + static const size_type npos; + typedef const char* const_iterator; + typedef const char* iterator; + typedef std::reverse_iterator const_reverse_iterator; + typedef std::reverse_iterator reverse_iterator; + iterator begin() const { return ptr_; } + iterator end() const { return ptr_ + length_; } + const_reverse_iterator rbegin() const { + return const_reverse_iterator(ptr_ + length_); + } + const_reverse_iterator rend() const { + return const_reverse_iterator(ptr_); + } + stringpiece_ssize_type max_size() const { return length_; } + stringpiece_ssize_type capacity() const { return length_; } + + // cpplint.py emits a false positive [build/include_what_you_use] + stringpiece_ssize_type copy(char* buf, size_type n, size_type pos = 0) const; // NOLINT + + bool contains(StringPiece s) const; + + stringpiece_ssize_type find(StringPiece s, size_type pos = 0) const; + stringpiece_ssize_type find(char c, size_type pos = 0) const; + stringpiece_ssize_type rfind(StringPiece s, size_type pos = npos) const; + stringpiece_ssize_type rfind(char c, size_type pos = npos) const; + + stringpiece_ssize_type find_first_of(StringPiece s, size_type pos = 0) const; + stringpiece_ssize_type find_first_of(char c, size_type pos = 0) const { + return find(c, pos); + } + stringpiece_ssize_type find_first_not_of(StringPiece s, + size_type pos = 0) const; + stringpiece_ssize_type find_first_not_of(char c, size_type pos = 0) const; + stringpiece_ssize_type find_last_of(StringPiece s, + size_type pos = npos) const; + stringpiece_ssize_type find_last_of(char c, size_type pos = npos) const { + return rfind(c, pos); + } + stringpiece_ssize_type find_last_not_of(StringPiece s, + size_type pos = npos) const; + stringpiece_ssize_type find_last_not_of(char c, size_type pos = npos) const; + + StringPiece substr(size_type pos, size_type n = npos) const; +}; + +// This large function is defined inline so that in a fairly common case where +// one of the arguments is a literal, the compiler can elide a lot of the +// following comparisons. +inline bool operator==(StringPiece x, StringPiece y) { + stringpiece_ssize_type len = x.size(); + if (len != y.size()) { + return false; + } + + return x.data() == y.data() || len <= 0 || + memcmp(x.data(), y.data(), len) == 0; +} + +inline bool operator!=(StringPiece x, StringPiece y) { + return !(x == y); +} + +inline bool operator<(StringPiece x, StringPiece y) { + const stringpiece_ssize_type min_size = + x.size() < y.size() ? x.size() : y.size(); + const int r = memcmp(x.data(), y.data(), min_size); + return (r < 0) || (r == 0 && x.size() < y.size()); +} + +inline bool operator>(StringPiece x, StringPiece y) { + return y < x; +} + +inline bool operator<=(StringPiece x, StringPiece y) { + return !(x > y); +} + +inline bool operator>=(StringPiece x, StringPiece y) { + return !(x < y); +} + +// allow StringPiece to be logged +extern std::ostream& operator<<(std::ostream& o, StringPiece piece); + +} // namespace protobuf +} // namespace google + +#endif // STRINGS_STRINGPIECE_H_ -- cgit v1.2.3