Open Lighting Architecture: include/ola/io/MemoryBlock.h Source File

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MemoryBlock.h
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1/*
2 * This library is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU Lesser General Public
4 * License as published by the Free Software Foundation; either
5 * version 2.1 of the License, or (at your option) any later version.
6 *
7 * This library is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * Lesser General Public License for more details.
11 *
12 * You should have received a copy of the GNU Lesser General Public
13 * License along with this library; if not, write to the Free Software
14 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
15 *
16 * MemoryBlock.h
17 * A block of memory.
18 * Copyright (C) 2013 Simon Newton
19 */
20
25
26#ifndef INCLUDE_OLA_IO_MEMORYBLOCK_H_
27#define INCLUDE_OLA_IO_MEMORYBLOCK_H_
28
29#include <stdint.h>
30#include <string.h>
31#include <algorithm>
32
33namespace ola {
34namespace io {
35
41 class MemoryBlock {
42 public:
49 MemoryBlock(uint8_t *data, unsigned int size)
50 : m_data(data),
51 m_data_end(data + size),
52 m_capacity(size),
53 m_first(data),
54 m_last(data) {
55 }
56
60 ~MemoryBlock() {
61 delete[] m_data;
62 }
63
68 void SeekBack() {
69 m_first = m_data_end;
70 m_last = m_first;
71 }
72
77 unsigned int Capacity() const { return m_capacity; }
78
83 unsigned int Remaining() const {
84 return static_cast<unsigned int>(m_data_end - m_last);
85 }
86
91 unsigned int Size() const {
92 return static_cast<unsigned int>(m_last - m_first);
93 }
94
99 bool Empty() const {
100 return m_last == m_first;
101 }
102
107 uint8_t *Data() const { return m_first; }
108
116 unsigned int Append(const uint8_t *data, unsigned int length) {
117 unsigned int bytes_to_write = std::min(
118 length, static_cast<unsigned int>(m_data_end - m_last));
119 memcpy(m_last, data, bytes_to_write);
120 m_last += bytes_to_write;
121 return bytes_to_write;
122 }
123
131 unsigned int Prepend(const uint8_t *data, unsigned int length) {
132 unsigned int bytes_to_write = std::min(
133 length, static_cast<unsigned int>(m_first - m_data));
134 memcpy(m_first - bytes_to_write, data + length - bytes_to_write,
135 bytes_to_write);
136 m_first -= bytes_to_write;
137 return bytes_to_write;
138 }
139
146 unsigned int Copy(uint8_t *data, unsigned int length) const {
147 unsigned int bytes_to_read = std::min(
148 length, static_cast<unsigned int>(m_last - m_first));
149 memcpy(data, m_first, bytes_to_read);
150 return bytes_to_read;
151 }
152
158 unsigned int PopFront(unsigned int length) {
159 unsigned int bytes_to_pop = std::min(
160 length, static_cast<unsigned int>(m_last - m_first));
161 m_first += bytes_to_pop;
162 // reset
163 if (m_first == m_last) {
164 m_first = m_data;
165 m_last = m_data;
166 }
167 return bytes_to_pop;
168 }
169
170 private:
171 uint8_t* const m_data;
172 uint8_t* const m_data_end;
173 unsigned int m_capacity;
174 // Points to the valid data in the block.
175 uint8_t *m_first;
176 uint8_t *m_last; // points to one after last
177};
178} // namespace io
179} // namespace ola
180#endif // INCLUDE_OLA_IO_MEMORYBLOCK_H_
ola::io::MemoryBlock::Data
uint8_t * Data() const
Provides a pointer to the first byte of valid data in this block.
Definition MemoryBlock.h:107
ola::io::MemoryBlock::MemoryBlock
MemoryBlock(uint8_t *data, unsigned int size)
Construct a new MemoryBlock.
Definition MemoryBlock.h:49
ola::io::MemoryBlock::Prepend
unsigned int Prepend(const uint8_t *data, unsigned int length)
Prepend data to this block.
Definition MemoryBlock.h:131
ola::io::MemoryBlock::~MemoryBlock
~MemoryBlock()
Destructor, this frees the memory for the block.
Definition MemoryBlock.h:60
ola::io::MemoryBlock::Append
unsigned int Append(const uint8_t *data, unsigned int length)
Append data to this block.
Definition MemoryBlock.h:116
ola::io::MemoryBlock::Capacity
unsigned int Capacity() const
The size of the memory region for this block.
Definition MemoryBlock.h:77
ola::io::MemoryBlock::Remaining
unsigned int Remaining() const
The free space at the end of the block.
Definition MemoryBlock.h:83
ola::io::MemoryBlock::Size
unsigned int Size() const
The size of data in this block.
Definition MemoryBlock.h:91
ola::io::MemoryBlock::Empty
bool Empty() const
Check if the block contains data.
Definition MemoryBlock.h:99
ola::io::MemoryBlock::SeekBack
void SeekBack()
Move the insertation point to the end of the block. This is useful if you want to use the block in pr...
Definition MemoryBlock.h:68
ola::io::MemoryBlock::PopFront
unsigned int PopFront(unsigned int length)
Remove data from the front of the block.
Definition MemoryBlock.h:158
ola::io::MemoryBlock::Copy
unsigned int Copy(uint8_t *data, unsigned int length) const
Definition MemoryBlock.h:146
ola::io
Classes for general I/O and event handling.
Definition Descriptor.cpp:49
ola
The namespace containing all OLA symbols.
Definition Credentials.cpp:44