59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
#include "ringbuf.h"
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#include <memory.h>
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void ringbuf_purge(ring_buffer_t* ring) {
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ring->read = 0;
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ring->write = 0;
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}
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short ringbuf_available(ring_buffer_t* ring) {
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short populated = ring->write - ring->read;
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if (populated < 0) populated += RING_BUFFER_SIZE;
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return populated;
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}
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bool ringbuf_write(ring_buffer_t* ring, unsigned const char* data, short bytes) {
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short unpopulated = ring->read - ring->write;
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if (unpopulated < 0) unpopulated += RING_BUFFER_SIZE;
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bool overflow = unpopulated < bytes;
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while (bytes > 0) {
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short chunk;
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if (bytes + ring->write > RING_BUFFER_SIZE)
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chunk = RING_BUFFER_SIZE - ring->write;
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else
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chunk = bytes;
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memcpy(ring->buffer + ring->write, data, chunk);
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data += chunk;
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bytes -= chunk;
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ring->write = (ring->write + chunk) % RING_BUFFER_SIZE;
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}
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return overflow;
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}
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short ringbuf_read(ring_buffer_t* ring, unsigned char* data, short bytes) {
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short populated = ring->write - ring->read;
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if (populated < 0) populated += RING_BUFFER_SIZE;
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// Underflow
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if (populated < bytes) bytes = populated;
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short left = bytes;
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while (left > 0) {
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short chunk;
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if (left + ring->read > RING_BUFFER_SIZE)
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chunk = RING_BUFFER_SIZE - ring->read;
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else
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chunk = left;
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memcpy(data, ring->buffer + ring->read, chunk);
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data += chunk;
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left -= chunk;
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ring->read = (ring->read + chunk) % RING_BUFFER_SIZE;
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}
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return bytes;
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}
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