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Diffstat (limited to 'base/fixed_string.h')
-rw-r--r-- | base/fixed_string.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/base/fixed_string.h b/base/fixed_string.h new file mode 100644 index 0000000..857b057 --- /dev/null +++ b/base/fixed_string.h @@ -0,0 +1,96 @@ +// Copyright 2008, Google Inc. +// All rights reserved. +// +// 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. + +#ifndef BASE_FIXED_STRING_H__ +#define BASE_FIXED_STRING_H__ + +#include <string.h> + +#include "base/string_util.h" + +// This class manages a fixed-size, null-terminated string buffer. It is meant +// to be allocated on the stack, and it makes no use of the heap internally. In +// most cases you'll just want to use a std::(w)string, but when you need to +// avoid the heap, you can use this class instead. +// +// Methods are provided to read the null-terminated buffer and to append data +// to the buffer, and once the buffer fills-up, it simply discards any extra +// append calls. +// +// Since this object clips if the internal fixed buffer is exceeded, it is +// appropriate for exception handlers where the heap may be corrupted. Fixed +// buffers that overflow onto the heap are provided by Stack[W]String. +// (see stack_container.h). +template <class CharT, int MaxSize> +class FixedString { + public: + typedef CharTraits<CharT> char_traits; + + FixedString() : index_(0), truncated_(false) { + buf_[0] = CharT(0); + } + + // Returns true if the Append ever failed. + bool was_truncated() const { return truncated_; } + + // Returns the number of characters in the string, excluding the null + // terminator. + size_t size() const { return index_; } + + // Returns the null-terminated string. + const CharT* get() const { return buf_; } + CharT* get() { return buf_; } + + // Append an array of characters. The operation is bounds checked, and if + // there is insufficient room, then the was_truncated() flag is set to true. + void Append(const CharT* s, size_t n) { + if (char_traits::copy_num(buf_ + index_, arraysize(buf_) - index_, s, n)) { + index_ += n; + } else { + truncated_ = true; + } + } + + // Append a null-terminated string. + void Append(const CharT* s) { + Append(s, char_traits::length(s)); + } + + // Append a single character. + void Append(CharT c) { + Append(&c, 1); + } + + private: + CharT buf_[MaxSize]; + size_t index_; + bool truncated_; +}; + +#endif // BASE_FIXED_STRING_H__ |