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00018 #ifndef RAUL_RING_BUFFER_HPP
00019 #define RAUL_RING_BUFFER_HPP
00020
00021 #include <cassert>
00022 #include <iostream>
00023 #include <glib.h>
00024
00025 namespace Raul {
00026
00027
00032 template <typename T>
00033 class RingBuffer {
00034 public:
00035
00038 RingBuffer(size_t size)
00039 : _size(size)
00040 , _buf(new T[size])
00041 {
00042 reset();
00043 assert(read_space() == 0);
00044 assert(write_space() == size - 1);
00045 }
00046
00047 virtual ~RingBuffer() {
00048 delete[] _buf;
00049 }
00050
00054 void reset() {
00055 g_atomic_int_set(&_write_ptr, 0);
00056 g_atomic_int_set(&_read_ptr, 0);
00057 }
00058
00059 size_t write_space() const {
00060
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
00075 const size_t w = g_atomic_int_get(&_write_ptr);
00076 const size_t r = g_atomic_int_get(&_read_ptr);
00077
00078 if (w > r) {
00079 return w - r;
00080 } else {
00081 return (w - r + _size) % _size;
00082 }
00083 }
00084
00085 size_t capacity() const { return _size; }
00086
00087 size_t peek(size_t size, T* dst);
00088 bool full_peek(size_t size, T* dst);
00089
00090 size_t read(size_t size, T* dst);
00091 bool full_read(size_t size, T* dst);
00092
00093 bool skip(size_t size);
00094
00095 void write(size_t size, const T* src);
00096
00097 protected:
00098 mutable int _write_ptr;
00099 mutable int _read_ptr;
00100
00101 size_t _size;
00102 T* _buf;
00103 };
00104
00105
00112 template<typename T>
00113 size_t
00114 RingBuffer<T>::peek(size_t size, T* dst)
00115 {
00116 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00117
00118 const size_t read_size = (priv_read_ptr + size < _size)
00119 ? size
00120 : _size - priv_read_ptr;
00121
00122 memcpy(dst, &_buf[priv_read_ptr], read_size);
00123
00124 return read_size;
00125 }
00126
00127
00128 template<typename T>
00129 bool
00130 RingBuffer<T>::full_peek(size_t size, T* dst)
00131 {
00132 if (read_space() < size) {
00133 return false;
00134 }
00135
00136 const size_t read_size = peek(size, dst);
00137
00138 if (read_size < size) {
00139 peek(size - read_size, dst + read_size);
00140 }
00141
00142 return true;
00143 }
00144
00145
00152 template<typename T>
00153 size_t
00154 RingBuffer<T>::read(size_t size, T* dst)
00155 {
00156 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00157
00158 const size_t read_size = (priv_read_ptr + size < _size)
00159 ? size
00160 : _size - priv_read_ptr;
00161
00162 memcpy(dst, &_buf[priv_read_ptr], read_size);
00163
00164 g_atomic_int_set(&_read_ptr, (priv_read_ptr + read_size) % _size);
00165
00166 return read_size;
00167 }
00168
00169
00170 template<typename T>
00171 bool
00172 RingBuffer<T>::full_read(size_t size, T* dst)
00173 {
00174 if (read_space() < size) {
00175 return false;
00176 }
00177
00178 const size_t read_size = read(size, dst);
00179
00180 if (read_size < size) {
00181 read(size - read_size, dst + read_size);
00182 }
00183
00184 return true;
00185 }
00186
00187
00188 template<typename T>
00189 bool
00190 RingBuffer<T>::skip(size_t size)
00191 {
00192 if (read_space() < size) {
00193 std::cerr << "WARNING: Attempt to skip past end of MIDI ring buffer" << std::endl;
00194 return false;
00195 }
00196
00197 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
00198 g_atomic_int_set(&_read_ptr, (priv_read_ptr + size) % _size);
00199
00200 return true;
00201 }
00202
00203
00204 template<typename T>
00205 inline void
00206 RingBuffer<T>::write(size_t size, const T* src)
00207 {
00208 const size_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
00209
00210 if (priv_write_ptr + size <= _size) {
00211 memcpy(&_buf[priv_write_ptr], src, size);
00212 g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
00213 } else {
00214 const size_t this_size = _size - priv_write_ptr;
00215 assert(this_size < size);
00216 assert(priv_write_ptr + this_size <= _size);
00217 memcpy(&_buf[priv_write_ptr], src, this_size);
00218 memcpy(&_buf[0], src+this_size, size - this_size);
00219 g_atomic_int_set(&_write_ptr, size - this_size);
00220 }
00221 }
00222
00223
00224 }
00225
00226 #endif // RAUL_RING_BUFFER_HPP
00227