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00018 #ifndef RAUL_RING_BUFFER_HPP
00019 #define RAUL_RING_BUFFER_HPP
00020
00021 #include <cassert>
00022 #include <cstring>
00023 #include <iostream>
00024 #include <glib.h>
00025
00026 namespace Raul {
00027
00028
00033 template <typename T>
00034 class RingBuffer {
00035 public:
00036
00039 RingBuffer(size_t size)
00040 : _size(size)
00041 , _buf(new T[size])
00042 {
00043 reset();
00044 assert(read_space() == 0);
00045 assert(write_space() == size - 1);
00046 }
00047
00048 virtual ~RingBuffer() {
00049 delete[] _buf;
00050 }
00051
00055 void reset() {
00056 g_atomic_int_set(&_write_ptr, 0);
00057 g_atomic_int_set(&_read_ptr, 0);
00058 }
00059
00060 size_t write_space() const {
00061 const size_t w = g_atomic_int_get(&_write_ptr);
00062 const size_t r = g_atomic_int_get(&_read_ptr);
00063
00064 if (w > r) {
00065 return ((r - w + _size) % _size) - 1;
00066 } else if (w < r) {
00067 return (r - w) - 1;
00068 } else {
00069 return _size - 1;
00070 }
00071 }
00072
00073 size_t read_space() const {
00074 const size_t w = g_atomic_int_get(&_write_ptr);
00075 const size_t r = g_atomic_int_get(&_read_ptr);
00076
00077 if (w > r) {
00078 return w - r;
00079 } else {
00080 return (w - r + _size) % _size;
00081 }
00082 }
00083
00084 size_t capacity() const { return _size; }
00085
00086 size_t peek(size_t size, T* dst);
00087 bool full_peek(size_t size, T* dst);
00088
00089 size_t read(size_t size, T* dst);
00090 bool full_read(size_t size, T* dst);
00091
00092 bool skip(size_t size);
00093
00094 void write(size_t size, const T* src);
00095
00096 protected:
00097 mutable int _write_ptr;
00098 mutable int _read_ptr;
00099
00100 size_t _size;
00101 T* _buf;
00102 };
00103
00104
00111 template<typename T>
00112 size_t
00113 RingBuffer<T>::peek(size_t size, T* dst)
00114 {
00115 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00116
00117 const size_t read_size = (priv_read_ptr + size < _size)
00118 ? size
00119 : _size - priv_read_ptr;
00120
00121 memcpy(dst, &_buf[priv_read_ptr], read_size);
00122
00123 return read_size;
00124 }
00125
00126
00127 template<typename T>
00128 bool
00129 RingBuffer<T>::full_peek(size_t size, T* dst)
00130 {
00131 if (read_space() < size) {
00132 return false;
00133 }
00134
00135 const size_t read_size = peek(size, dst);
00136
00137 if (read_size < size) {
00138 peek(size - read_size, dst + read_size);
00139 }
00140
00141 return true;
00142 }
00143
00144
00151 template<typename T>
00152 size_t
00153 RingBuffer<T>::read(size_t size, T* dst)
00154 {
00155 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00156
00157 const size_t read_size = (priv_read_ptr + size < _size)
00158 ? size
00159 : _size - priv_read_ptr;
00160
00161 memcpy(dst, &_buf[priv_read_ptr], read_size);
00162
00163 g_atomic_int_set(&_read_ptr, (priv_read_ptr + read_size) % _size);
00164
00165 return read_size;
00166 }
00167
00168
00169 template<typename T>
00170 bool
00171 RingBuffer<T>::full_read(size_t size, T* dst)
00172 {
00173 if (read_space() < size) {
00174 return false;
00175 }
00176
00177 const size_t read_size = read(size, dst);
00178
00179 if (read_size < size) {
00180 read(size - read_size, dst + read_size);
00181 }
00182
00183 return true;
00184 }
00185
00186
00187 template<typename T>
00188 bool
00189 RingBuffer<T>::skip(size_t size)
00190 {
00191 if (read_space() < size) {
00192 std::cerr << "WARNING: Attempt to skip past end of MIDI ring buffer" << std::endl;
00193 return false;
00194 }
00195
00196 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00197 g_atomic_int_set(&_read_ptr, (priv_read_ptr + size) % _size);
00198
00199 return true;
00200 }
00201
00202
00203 template<typename T>
00204 inline void
00205 RingBuffer<T>::write(size_t size, const T* src)
00206 {
00207 const size_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
00208
00209 if (priv_write_ptr + size <= _size) {
00210 memcpy(&_buf[priv_write_ptr], src, size);
00211 g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
00212 } else {
00213 const size_t this_size = _size - priv_write_ptr;
00214 assert(this_size < size);
00215 assert(priv_write_ptr + this_size <= _size);
00216 memcpy(&_buf[priv_write_ptr], src, this_size);
00217 memcpy(&_buf[0], src+this_size, size - this_size);
00218 g_atomic_int_set(&_write_ptr, size - this_size);
00219 }
00220 }
00221
00222
00223 }
00224
00225 #endif // RAUL_RING_BUFFER_HPP
00226