// Taken from PCRE pcre_stringpiece.h
//
// Copyright (c) 2005, 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.
//
// Author: Sanjay Ghemawat
//
// A string like object that points into another piece of memory.
// Useful for providing an interface that allows clients to easily
// pass in either a "const char*" or a "string".
//
// Arghh!  I wish C++ literals were automatically of type "string".

#ifndef MUDUO_BASE_STRINGPIECE_H
#define MUDUO_BASE_STRINGPIECE_H

#include <string.h>
#include <iosfwd>    // for ostream forward-declaration

#include "Types.h"

namespace muduo
{

// For passing C-style string argument to a function.
    class StringArg // copyable
    {
    public:
        StringArg(const char* str)
                : str_(str)
        { }

        StringArg(const string& str)
                : str_(str.c_str())
        { }

        const char* c_str() const { return str_; }

    private:
        const char* str_;
    };

    class StringPiece {
    private:
        const char*   ptr_;
        int           length_;

    public:
        // We provide non-explicit singleton constructors so users can pass
        // in a "const char*" or a "string" wherever a "StringPiece" is
        // expected.
        StringPiece()
                : ptr_(NULL), length_(0) { }
        StringPiece(const char* str)
                : ptr_(str), length_(static_cast<int>(strlen(ptr_))) { }
        StringPiece(const unsigned char* str)
                : ptr_(reinterpret_cast<const char*>(str)),
                  length_(static_cast<int>(strlen(ptr_))) { }
        StringPiece(const string& str)
                : ptr_(str.data()), length_(static_cast<int>(str.size())) { }
        StringPiece(const char* offset, int len)
                : ptr_(offset), length_(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.  Use "as_string().c_str()" if you really need to do
        // this.  Or better yet, change your routine so it does not rely on NUL
        // termination.
        const char* data() const { return ptr_; }
        int size() const { return length_; }
        bool empty() const { return length_ == 0; }
        const char* begin() const { return ptr_; }
        const char* end() const { return ptr_ + length_; }

        void clear() { ptr_ = NULL; length_ = 0; }
        void set(const char* buffer, int len) { ptr_ = buffer; length_ = len; }
        void set(const char* str) {
            ptr_ = str;
            length_ = static_cast<int>(strlen(str));
        }
        void set(const void* buffer, int len) {
            ptr_ = reinterpret_cast<const char*>(buffer);
            length_ = len;
        }

        char operator[](int i) const { return ptr_[i]; }

        void remove_prefix(int n) {
            ptr_ += n;
            length_ -= n;
        }

        void remove_suffix(int n) {
            length_ -= n;
        }

        bool operator==(const StringPiece& x) const {
            return ((length_ == x.length_) &&
                    (memcmp(ptr_, x.ptr_, length_) == 0));
        }
        bool operator!=(const StringPiece& x) const {
            return !(*this == x);
        }

#define STRINGPIECE_BINARY_PREDICATE(cmp,auxcmp)                             \
  bool operator cmp (const StringPiece& x) const {                           \
    int r = memcmp(ptr_, x.ptr_, length_ < x.length_ ? length_ : x.length_); \
    return ((r auxcmp 0) || ((r == 0) && (length_ cmp x.length_)));          \
  }
        STRINGPIECE_BINARY_PREDICATE(<,  <);
        STRINGPIECE_BINARY_PREDICATE(<=, <);
        STRINGPIECE_BINARY_PREDICATE(>=, >);
        STRINGPIECE_BINARY_PREDICATE(>,  >);
#undef STRINGPIECE_BINARY_PREDICATE

        int compare(const StringPiece& x) const {
            int r = memcmp(ptr_, x.ptr_, length_ < x.length_ ? length_ : x.length_);
            if (r == 0) {
                if (length_ < x.length_) r = -1;
                else if (length_ > x.length_) r = +1;
            }
            return r;
        }

        string as_string() const {
            return string(data(), size());
        }

        void CopyToString(string* target) const {
            target->assign(ptr_, length_);
        }

        // Does "this" start with "x"
        bool starts_with(const StringPiece& x) const {
            return ((length_ >= x.length_) && (memcmp(ptr_, x.ptr_, x.length_) == 0));
        }
    };

}  // namespace muduo

// ------------------------------------------------------------------
// Functions used to create STL containers that use StringPiece
//  Remember that a StringPiece's lifetime had better be less than
//  that of the underlying string or char*.  If it is not, then you
//  cannot safely store a StringPiece into an STL container
// ------------------------------------------------------------------

#ifdef HAVE_TYPE_TRAITS
// This makes vector<StringPiece> really fast for some STL implementations
template<> struct __type_traits<muduo::StringPiece> {
  typedef __true_type    has_trivial_default_constructor;
  typedef __true_type    has_trivial_copy_constructor;
  typedef __true_type    has_trivial_assignment_operator;
  typedef __true_type    has_trivial_destructor;
  typedef __true_type    is_POD_type;
};
#endif

// allow StringPiece to be logged
std::ostream& operator<<(std::ostream& o, const muduo::StringPiece& piece);

#endif  // MUDUO_BASE_STRINGPIECE_H
