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/*************************************************************************
** InputBuffer.cpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2023 Martin Gieseking <martin.gieseking@uos.de> **
** **
** This program is free software; you can redistribute it and/or **
** modify it under the terms of the GNU General Public License as **
** published by the Free Software Foundation; either version 3 of **
** the License, or (at your option) any later version. **
** **
** This program is distributed in the hope that it will be useful, but **
** WITHOUT ANY WARRANTY; without even the implied warranty of **
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the **
** GNU General Public License for more details. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#include <cmath>
#include <cstring>
#include "InputBuffer.hpp"
using namespace std;
StreamInputBuffer::StreamInputBuffer (istream &is, size_t bufsize)
: _is(is), _buf1(bufsize), _buf2(bufsize)
{
_size1 = fillBuffer(_buf1);
_size2 = fillBuffer(_buf2);
}
/** Returns the next character from the input buffer (or -1 if there's none). */
int StreamInputBuffer::get () {
if (_pos == _size1) {
if (_size2 == 0)
return -1;
swap(_buf1, _buf2); // O(1) swap of memory buffers
_size1 = _size2;
_pos = 0;
_size2 = fillBuffer(_buf2);
}
return _buf1[_pos++];
}
/** Returns the next character to be read without skipping it.
* Same as peek(0). */
int StreamInputBuffer::peek () const {
if (_pos < _size1)
return _buf1[_pos];
return _size2 > 0 ? _buf2[0] : -1;
}
/** Returns the n-th next character without skipping it. */
int StreamInputBuffer::peek (size_t n) const {
if (_pos+n < _size1)
return _buf1[_pos+n];
if (_pos+n < _size1+_size2)
return _buf2[_pos+n-_size1];
return -1;
}
/** Fills the buffer by reading a sequence of characters from the assigned input stream.
* @param[in] buf buffer to be filled
* @return number of characters read */
size_t StreamInputBuffer::fillBuffer (vector<uint8_t> &buf) {
if (_is && !_is.eof()) {
_is.read(reinterpret_cast<char*>(buf.data()), streamsize(buf.size()));
return _is.gcount();
}
return 0;
}
///////////////////////////////////////////////
SplittedCharInputBuffer::SplittedCharInputBuffer (const char *buf1, size_t s1, const char *buf2, size_t s2) {
_buf[0] = buf1;
_buf[1] = buf2;
_size[0] = buf1 ? s1 : 0;
_size[1] = buf2 ? s2 : 0;
_index = _size[0] ? 0 : 1;
}
int SplittedCharInputBuffer::get () {
if (_size[_index] == 0)
return -1;
int ret = *_buf[_index]++;
_size[_index]--;
if (_index == 0 && _size[0] == 0)
_index++;
return ret;
}
int SplittedCharInputBuffer::peek () const {
return _size[_index] ? *_buf[_index] : -1;
}
int SplittedCharInputBuffer::peek (size_t n) const {
if (n < _size[_index])
return _buf[_index][n];
n -= _size[_index];
if (_index == 0 && n < _size[1])
return _buf[1][n];
return -1;
}
///////////////////////////////////////////////
int TextStreamInputBuffer::get () {
int c = StreamInputBuffer::get();
if (c == '\n') {
_line++;
_col = 1;
}
else
_col++;
return c;
}
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