|
| 1 | +/* |
| 2 | + cbuf.cpp - Circular buffer implementation |
| 3 | + Copyright (c) 2014 Ivan Grokhotkov. All rights reserved. |
| 4 | + This file is part of the esp8266 core for Arduino environment. |
| 5 | +
|
| 6 | + This library is free software; you can redistribute it and/or |
| 7 | + modify it under the terms of the GNU Lesser General Public |
| 8 | + License as published by the Free Software Foundation; either |
| 9 | + version 2.1 of the License, or (at your option) any later version. |
| 10 | +
|
| 11 | + This library is distributed in the hope that it will be useful, |
| 12 | + but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | + Lesser General Public License for more details. |
| 15 | +
|
| 16 | + You should have received a copy of the GNU Lesser General Public |
| 17 | + License along with this library; if not, write to the Free Software |
| 18 | + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | + */ |
| 20 | + |
| 21 | +#include "cbuf.h" |
| 22 | + |
| 23 | +cbuf::cbuf(size_t size) : |
| 24 | + next(NULL), _size(size+1), _buf(new char[size+1]), _bufend(_buf + size + 1), _begin(_buf), _end(_begin) |
| 25 | +{ |
| 26 | +} |
| 27 | + |
| 28 | +cbuf::~cbuf() |
| 29 | +{ |
| 30 | + delete[] _buf; |
| 31 | +} |
| 32 | + |
| 33 | +size_t cbuf::resizeAdd(size_t addSize) |
| 34 | +{ |
| 35 | + return resize(_size + addSize); |
| 36 | +} |
| 37 | + |
| 38 | +size_t cbuf::resize(size_t newSize) |
| 39 | +{ |
| 40 | + |
| 41 | + size_t bytes_available = available(); |
| 42 | + newSize += 1; |
| 43 | + // not lose any data |
| 44 | + // if data can be lost use remove or flush before resize |
| 45 | + if((newSize < bytes_available) || (newSize == _size)) { |
| 46 | + return _size; |
| 47 | + } |
| 48 | + |
| 49 | + char *newbuf = new char[newSize]; |
| 50 | + char *oldbuf = _buf; |
| 51 | + |
| 52 | + if(!newbuf) { |
| 53 | + return _size; |
| 54 | + } |
| 55 | + |
| 56 | + if(_buf) { |
| 57 | + read(newbuf, bytes_available); |
| 58 | + memset((newbuf + bytes_available), 0x00, (newSize - bytes_available)); |
| 59 | + } |
| 60 | + |
| 61 | + _begin = newbuf; |
| 62 | + _end = newbuf + bytes_available; |
| 63 | + _bufend = newbuf + newSize; |
| 64 | + _size = newSize; |
| 65 | + |
| 66 | + _buf = newbuf; |
| 67 | + delete[] oldbuf; |
| 68 | + |
| 69 | + return _size; |
| 70 | +} |
| 71 | + |
| 72 | +size_t cbuf::available() const |
| 73 | +{ |
| 74 | + if(_end >= _begin) { |
| 75 | + return _end - _begin; |
| 76 | + } |
| 77 | + return _size - (_begin - _end); |
| 78 | +} |
| 79 | + |
| 80 | +size_t cbuf::size() |
| 81 | +{ |
| 82 | + return _size; |
| 83 | +} |
| 84 | + |
| 85 | +size_t cbuf::room() const |
| 86 | +{ |
| 87 | + if(_end >= _begin) { |
| 88 | + return _size - (_end - _begin) - 1; |
| 89 | + } |
| 90 | + return _begin - _end - 1; |
| 91 | +} |
| 92 | + |
| 93 | +int cbuf::peek() |
| 94 | +{ |
| 95 | + if(empty()) { |
| 96 | + return -1; |
| 97 | + } |
| 98 | + |
| 99 | + return static_cast<int>(*_begin); |
| 100 | +} |
| 101 | + |
| 102 | +size_t cbuf::peek(char *dst, size_t size) |
| 103 | +{ |
| 104 | + size_t bytes_available = available(); |
| 105 | + size_t size_to_read = (size < bytes_available) ? size : bytes_available; |
| 106 | + size_t size_read = size_to_read; |
| 107 | + char * begin = _begin; |
| 108 | + if(_end < _begin && size_to_read > (size_t) (_bufend - _begin)) { |
| 109 | + size_t top_size = _bufend - _begin; |
| 110 | + memcpy(dst, _begin, top_size); |
| 111 | + begin = _buf; |
| 112 | + size_to_read -= top_size; |
| 113 | + dst += top_size; |
| 114 | + } |
| 115 | + memcpy(dst, begin, size_to_read); |
| 116 | + return size_read; |
| 117 | +} |
| 118 | + |
| 119 | +int cbuf::read() |
| 120 | +{ |
| 121 | + if(empty()) { |
| 122 | + return -1; |
| 123 | + } |
| 124 | + |
| 125 | + char result = *_begin; |
| 126 | + _begin = wrap_if_bufend(_begin + 1); |
| 127 | + return static_cast<int>(result); |
| 128 | +} |
| 129 | + |
| 130 | +size_t cbuf::read(char* dst, size_t size) |
| 131 | +{ |
| 132 | + size_t bytes_available = available(); |
| 133 | + size_t size_to_read = (size < bytes_available) ? size : bytes_available; |
| 134 | + size_t size_read = size_to_read; |
| 135 | + if(_end < _begin && size_to_read > (size_t) (_bufend - _begin)) { |
| 136 | + size_t top_size = _bufend - _begin; |
| 137 | + memcpy(dst, _begin, top_size); |
| 138 | + _begin = _buf; |
| 139 | + size_to_read -= top_size; |
| 140 | + dst += top_size; |
| 141 | + } |
| 142 | + memcpy(dst, _begin, size_to_read); |
| 143 | + _begin = wrap_if_bufend(_begin + size_to_read); |
| 144 | + return size_read; |
| 145 | +} |
| 146 | + |
| 147 | +size_t cbuf::write(char c) |
| 148 | +{ |
| 149 | + if(full()) { |
| 150 | + return 0; |
| 151 | + } |
| 152 | + |
| 153 | + *_end = c; |
| 154 | + _end = wrap_if_bufend(_end + 1); |
| 155 | + return 1; |
| 156 | +} |
| 157 | + |
| 158 | +size_t cbuf::write(const char* src, size_t size) |
| 159 | +{ |
| 160 | + size_t bytes_available = room(); |
| 161 | + size_t size_to_write = (size < bytes_available) ? size : bytes_available; |
| 162 | + size_t size_written = size_to_write; |
| 163 | + if(_end >= _begin && size_to_write > (size_t) (_bufend - _end)) { |
| 164 | + size_t top_size = _bufend - _end; |
| 165 | + memcpy(_end, src, top_size); |
| 166 | + _end = _buf; |
| 167 | + size_to_write -= top_size; |
| 168 | + src += top_size; |
| 169 | + } |
| 170 | + memcpy(_end, src, size_to_write); |
| 171 | + _end = wrap_if_bufend(_end + size_to_write); |
| 172 | + return size_written; |
| 173 | +} |
| 174 | + |
| 175 | +void cbuf::flush() |
| 176 | +{ |
| 177 | + _begin = _buf; |
| 178 | + _end = _buf; |
| 179 | +} |
| 180 | + |
| 181 | +size_t cbuf::remove(size_t size) |
| 182 | +{ |
| 183 | + size_t bytes_available = available(); |
| 184 | + if(size >= bytes_available) { |
| 185 | + flush(); |
| 186 | + return 0; |
| 187 | + } |
| 188 | + size_t size_to_remove = (size < bytes_available) ? size : bytes_available; |
| 189 | + if(_end < _begin && size_to_remove > (size_t) (_bufend - _begin)) { |
| 190 | + size_t top_size = _bufend - _begin; |
| 191 | + _begin = _buf; |
| 192 | + size_to_remove -= top_size; |
| 193 | + } |
| 194 | + _begin = wrap_if_bufend(_begin + size_to_remove); |
| 195 | + return available(); |
| 196 | +} |
0 commit comments