/*
* Copyright (C) 2009 The Android Open Source Project
* 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.
*
* 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.
*/
#include <string>
#include <algorithm>
#include <climits>
#include <cstddef>
#include <cstring>
#include <malloc.h>
#ifndef MAX_SIZE_T
#define MAX_SIZE_T (~(size_t)0)
#endif
namespace {
char kEmptyString[1] = { '\0' };
}
namespace std {
// Implementation of the std::string class.
//
// mData points either to a heap allocated array of bytes or the constant
// kEmptyString when empty and reserve has not been called.
//
// The size of the buffer pointed by mData is mCapacity + 1.
// The extra byte is need to store the '\0'.
//
// mCapacity is either mLength or the number of bytes reserved using
// reserve(int)).
//
// mLength is the number of char in the string, excluding the terminating '\0'.
//
// TODO: replace the overflow checks with some better named macros.
//
// Allocate n + 1 number of bytes for the string. Update mCapacity.
// Ensure that mCapacity + 1 and mLength + 1 is accessible.
// In case of error the original state of the string is restored.
// @param n Number of bytes requested. String allocate n + 1 to hold
// the terminating '\0'.
// @return true if the buffer could be allocated, false otherwise.
bool string::SafeMalloc(size_type n)
{
// Not empty and no overflow
if (n > 0 && n + 1 > n)
{
value_type *oldData = mData;
mData = static_cast<value_type *>(::malloc(n + 1));
if (NULL != mData)
{
mCapacity = n;
return true;
}
mData = oldData; // roll back
}
return false;
}
// Resize the buffer pointed by mData if n >= mLength.
// mData points to an allocated buffer or the empty string.
// @param n The number of bytes for the internal buffer.
// Must be > mLength and > 0.
void string::SafeRealloc(size_type n)
{
// truncation or nothing to do or n too big (overflow)
if (n < mLength || n == mCapacity || n + 1 < n) {
return;
}
if (kEmptyString == mData)
{
if (SafeMalloc(n)) {
*mData = '\0';
}
return;
}
value_type *oldData = mData;
mData = static_cast<char*>(::realloc(mData, n + 1));
if (NULL == mData) // reallocate failed.
{
mData = oldData;
}
else
{
mCapacity = n;
}
}
void string::SafeFree(value_type *buffer)
{
if (buffer != kEmptyString)
{
::free(buffer);
}
}
// If the memory is on the heap, release it. Do nothing we we point at the empty
// string. On return mData points to str.
void string::ResetTo(value_type *str)
{
SafeFree(mData);
mData = str;
}
void string::ConstructEmptyString()
{
mData = kEmptyString;
mLength = 0;
mCapacity = 0;
}
void string::Constructor(const value_type *str, size_type pos, size_type n)
{
// Enough data and no overflow
if (SafeMalloc(n))
{
memcpy(mData, str + pos, n);
mLength = n;
mData[mLength] = '\0';
return; // Success
}
ConstructEmptyString();
}
void string::Constructor(size_type n, char c)
{
// Enough data and no overflow
if (SafeMalloc(n))
{
memset(mData, c, n);
mLength = n;
mData[mLength] = '\0';
return; // Success
}
ConstructEmptyString();
}
string::string()
{
ConstructEmptyString();
}
string::string(const string& str, size_type pos, size_type n)
{
if (pos < str.mLength)
{
if (npos == n)
{
Constructor(str.mData, pos , str.mLength - pos);
return;
}
else if (n <= (str.mLength - pos))
{
Constructor(str.mData, pos , n);
return;
}
}
ConstructEmptyString();
}
string::string(const value_type *str)
{
if (NULL != str)
{
Constructor(str, 0, strlen(str));
}
else
{
ConstructEmptyString();
}
}
string::string(const value_type *str, size_type n)
{
if (npos != n)
{
Constructor(str, 0, n);
}
else
{
ConstructEmptyString(); // standard requires we throw length_error here.
}
}
// Char repeat constructor.
string::string(size_type n, char c)
{
Constructor(n, c);
}
string::string(const value_type *begin, const value_type *end)
{
if (begin < end)
{
Constructor(begin, 0, end - begin);
}
else
{
ConstructEmptyString();
}
}
string::~string()
{
clear(); // non virtual, ok to call.
}
void string::clear()
{
mCapacity = 0;
mLength = 0;
ResetTo(kEmptyString);
}
string& string::erase(size_type pos, size_type n)
{
if (pos >= mLength || 0 == n)
{
return *this;
}
// start of the characters left which need to be moved down.
const size_t remainder = pos + n;
// Truncate, even if there is an overflow.
if (remainder >= mLength || remainder < pos)
{
*(mData + pos) = '\0';
mLength = pos;
return *this;
}
// remainder < mLength and allocation guarantees to be at least
// mLength + 1
size_t left = mLength - remainder + 1;
value_type *d = mData + pos;
value_type *s = mData + remainder;
memmove(d, s, left);
mLength -= n;
return *this;
}
void string::Append(const value_type *str, size_type n)
{
const size_type total_len = mLength + n;
// n > 0 and no overflow for the string length + terminating null.
if (n > 0 && (total_len + 1) > mLength)
{
if (total_len > mCapacity)
{
reserve(total_len);
if (total_len > mCapacity)
{ // something went wrong in the reserve call.
return;
}
}
memcpy(mData + mLength, str, n);
mLength = total_len;
mData[mLength] = '\0';
}
}
string& string::append(const value_type *str)
{
if (NULL != str)
{
Append(str, strlen(str));
}
return *this;
}
string& string::append(const value_type *str, size_type n)
{
if (NULL != str)
{
Append(str, n);
}
return *this;
}
string& string::append(const value_type *str, size_type pos, size_type n)
{
if (NULL != str)
{
Append(str + pos, n);
}
return *this;
}
string& string::append(const string& str)
{
Append(str.mData, str.mLength);
return *this;
}
void string::push_back(const char c)
{
// Check we don't overflow.
if (mLength + 2 > mLength)
{
const size_type total_len = mLength + 1;
if (total_len > mCapacity)
{
reserve(total_len);
if (total_len > mCapacity)
{ // something went wrong in the reserve call.
return;
}
}
*(mData + mLength) = c;
++mLength;
mData[mLength] = '\0';
}
}
int string::compare(const string& other) const
{
if (this == &other)
{
return 0;
}
else if (mLength == other.mLength)
{
return memcmp(mData, other.mData, mLength);
}
else
{
return mLength < other.mLength ? -1 : 1;
}
}
int string::compare(const value_type *other) const
{
if (NULL == other)
{
return 1;
}
return strcmp(mData, other);
}
bool operator==(const string& left, const string& right)
{
if (&left == &right)
{
return true;
}
else
{
// We can use strcmp here because even when the string is build from an
// array of char we insert the terminating '\0'.
return strcmp(left.mData, right.mData) == 0;
}
}
bool operator==(const string& left, const string::value_type *right)
{
if (NULL == right)
{
return false;
}
// We can use strcmp here because even when the string is build from an
// array of char we insert the terminating '\0'.
return std::strcmp(left.mData, right) == 0;
}
void string::reserve(size_type size)
{
if (0 == size)
{
if (0 == mCapacity)
{
return;
}
else if (0 == mLength)
{ // Shrink to fit an empty string.
mCapacity = 0;
ResetTo(kEmptyString);
}
else
{ // Shrink to fit a non empty string
SafeRealloc(mLength);
}
}
else if (size > mLength)
{
SafeRealloc(size);
}
}
void string::swap(string& other)
{
if (this == &other) return;
value_type *const tmp_mData = mData;
const size_type tmp_mCapacity = mCapacity;
const size_type tmp_mLength = mLength;
mData = other.mData;
mCapacity = other.mCapacity;
mLength = other.mLength;
other.mData = tmp_mData;
other.mCapacity = tmp_mCapacity;
other.mLength = tmp_mLength;
}
const char& string::operator[](const size_type pos) const
{
return mData[pos];
}
char& string::operator[](const size_type pos)
{
return mData[pos];
}
string& string::assign(const string& str)
{
clear();
Constructor(str.mData, 0, str.mLength);
return *this;
}
string& string::assign(const string& str, size_type pos, size_type n)
{
if (pos >= str.mLength)
{ // pos is out of bound
return *this;
}
if (n <= str.mLength - pos)
{
clear();
Constructor(str.mData, pos, n);
}
return *this;
}
string& string::assign(const value_type *str)
{
if (NULL == str)
{
return *this;
}
clear();
Constructor(str, 0, strlen(str));
return *this;
}
string& string::assign(const value_type *array, size_type n)
{
if (NULL == array || 0 == n)
{
return *this;
}
clear();
Constructor(array, 0, n);
return *this;
}
string& string::operator=(char c)
{
clear();
Constructor(1, c);
return *this;
}
string::size_type string::find(const value_type *str, size_type pos) const
{
if (NULL == str)
{
return string::npos;
}
// Empty string is found everywhere except beyond the end. It is
// possible to find the empty string right after the last char,
// hence we used mLength and not mLength - 1 in the comparison.
if (*str == '\0')
{
return pos > mLength ? string::npos : pos;
}
if (mLength == 0 || pos > mLength - 1)
{
return string::npos;
}
value_type *idx = std::strstr(mData + pos, str);
if (NULL == idx)
{
return string::npos;
}
return static_cast<size_type>(idx - mData);
}
} // namespace std