137 lines
3.9 KiB
C++
137 lines
3.9 KiB
C++
#ifndef _CIRCULAR_BUFFER_H_
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#define _CIRCULAR_BUFFER_H_
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#include <algorithm>
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#include <vector>
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long const silence_threshold = 8;
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template <typename T>
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class circular_buffer {
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std::vector<T> buffer;
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unsigned long readptr, writeptr, used, size;
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unsigned long silence_count;
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T last_written[2];
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T last_read[2];
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public:
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circular_buffer()
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: readptr(0), writeptr(0), size(0), used(0), silence_count(0) {
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memset(last_written, 0, sizeof(last_written));
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memset(last_read, 0, sizeof(last_read));
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}
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unsigned long data_available() {
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return used;
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}
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unsigned long free_space() {
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return size - used;
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}
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T* get_write_ptr(unsigned long& count_out) {
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count_out = size - writeptr;
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if(count_out > size - used) count_out = size - used;
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return &buffer[writeptr];
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}
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bool samples_written(unsigned long count) {
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unsigned long max_count = size - writeptr;
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if(max_count > size - used) max_count = size - used;
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if(count > max_count) return false;
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silence_count += count_silent(&buffer[0] + writeptr, &buffer[0] + writeptr + count, last_written);
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used += count;
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writeptr = (writeptr + count) % size;
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return true;
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}
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unsigned long read(T* dst, unsigned long count) {
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unsigned long done = 0;
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for(;;) {
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unsigned long delta = size - readptr;
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if(delta > used) delta = used;
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if(delta > count) delta = count;
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if(!delta) break;
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if(dst) std::copy(buffer.begin() + readptr, buffer.begin() + readptr + delta, dst);
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silence_count -= count_silent(&buffer[0] + readptr, &buffer[0] + readptr + delta, last_read);
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if(dst) dst += delta;
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done += delta;
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readptr = (readptr + delta) % size;
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count -= delta;
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used -= delta;
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}
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return done;
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}
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void reset() {
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readptr = writeptr = used = 0;
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memset(last_written, 0, sizeof(last_written));
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memset(last_read, 0, sizeof(last_read));
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}
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void resize(unsigned long p_size) {
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size = p_size;
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buffer.resize(p_size);
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reset();
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}
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bool test_silence() const {
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return silence_count == used;
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}
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void remove_leading_silence() {
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T const* p;
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T const* begin;
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T const* end;
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if(used) {
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long delta[2];
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p = begin = &buffer[0] + readptr;
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end = &buffer[0] + (writeptr > readptr ? writeptr : size);
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while(p < end) {
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delta[0] = p[0] - last_read[0];
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delta[1] = p[1] - last_read[1];
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if(((unsigned long)(delta[0] + silence_threshold) > (unsigned long)silence_threshold * 2) ||
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((unsigned long)(delta[1] + silence_threshold) > (unsigned long)silence_threshold * 2))
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break;
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last_read[0] += (T)delta[0];
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last_read[1] += (T)delta[1];
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p += 2;
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}
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unsigned long skipped = p - begin;
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silence_count -= skipped;
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used -= skipped;
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readptr = (readptr + skipped) % size;
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if(readptr == 0 && readptr != writeptr) {
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p = begin = &buffer[0];
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end = &buffer[0] + writeptr;
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while(p < end) {
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delta[0] = p[0] - last_read[0];
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delta[1] = p[1] - last_read[1];
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if(((unsigned long)(delta[0] + silence_threshold) > (unsigned long)silence_threshold * 2) ||
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((unsigned long)(delta[1] + silence_threshold) > (unsigned long)silence_threshold * 2))
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break;
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last_read[0] += (T)delta[0];
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last_read[1] += (T)delta[1];
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p += 2;
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}
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skipped = p - begin;
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silence_count -= skipped;
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used -= skipped;
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readptr += skipped;
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}
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}
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}
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private:
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static unsigned long count_silent(T const* begin, T const* end, T* last) {
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unsigned long count = 0;
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T const* p = begin;
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long delta[2];
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while(p < end) {
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delta[0] = p[0] - last[0];
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delta[1] = p[1] - last[1];
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if(((unsigned long)(delta[0] + silence_threshold) <= (unsigned long)silence_threshold * 2) ||
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((unsigned long)(delta[1] + silence_threshold) <= (unsigned long)silence_threshold * 2))
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count += 2;
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last[0] += (T)delta[0];
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last[1] += (T)delta[1];
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p += 2;
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}
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return count;
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}
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};
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#endif
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