104 lines
3.3 KiB
C
104 lines
3.3 KiB
C
/*
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ringbuffer.h
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ring buffer
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Copyright (C) 2020 Bill Currie <bill@taniwha.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifndef __QF_ringbuffer_h
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#define __QF_ringbuffer_h
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#define RING_BUFFER(type, size) \
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struct { \
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type buffer[size]; \
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unsigned head; \
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unsigned tail; \
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}
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#define RB_buffer_size(ring_buffer) \
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({ __auto_type rb = (ring_buffer); \
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sizeof (rb->buffer) / sizeof (rb->buffer[0]); \
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})
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#define RB_SPACE_AVAILABLE(ring_buffer) \
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({ __auto_type rb = &(ring_buffer); \
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(rb->tail + RB_buffer_size(rb) - rb->head - 1) % RB_buffer_size(rb);\
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})
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#define RB_DATA_AVAILABLE(ring_buffer) \
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({ __auto_type rb = &(ring_buffer); \
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(rb->head + RB_buffer_size (rb) - rb->tail) % RB_buffer_size (rb); \
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})
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#define RB_WRITE_DATA(ring_buffer, data, count) \
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({ __auto_type rb = &(ring_buffer); \
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const typeof (rb->buffer[0]) *d = (data); \
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unsigned c = (count); \
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unsigned h = rb->head; \
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rb->head = (h + c) % RB_buffer_size (rb); \
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if (c > RB_buffer_size (rb) - h) { \
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memcpy (rb->buffer + h, d, \
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(RB_buffer_size (rb) - h) * sizeof (rb->buffer[0])); \
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c -= RB_buffer_size (rb) - h; \
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d += RB_buffer_size (rb) - h; \
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h = 0; \
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} \
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memcpy (rb->buffer + h, d, c * sizeof (rb->buffer[0])); \
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})
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#define RB_READ_DATA(ring_buffer, data, count) \
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({ __auto_type rb = &(ring_buffer); \
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typeof (&rb->buffer[0]) d = (data); \
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unsigned c = (count); \
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unsigned oc = c; \
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unsigned t = rb->tail; \
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if (c > RB_buffer_size (rb) - t) { \
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memcpy (d, rb->buffer + t, \
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(RB_buffer_size (rb) - t) * sizeof (rb->buffer[0])); \
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c -= RB_buffer_size (rb) - t; \
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d += RB_buffer_size (rb) - t; \
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t = 0; \
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} \
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memcpy (d, rb->buffer + t, c * sizeof (rb->buffer[0])); \
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rb->tail = (t + oc) % RB_buffer_size (rb); \
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})
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#define RB_DROP_DATA(ring_buffer, count) \
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({ __auto_type rb = &(ring_buffer); \
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unsigned c = (count); \
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unsigned t = rb->tail; \
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rb->tail = (t + c) % RB_buffer_size (rb); \
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})
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#define RB_PEEK_DATA(ring_buffer, ahead) \
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({ __auto_type rb = &(ring_buffer); \
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rb->buffer[(rb->tail + ahead) % RB_buffer_size (rb)]; \
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})
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#define RB_POKE_DATA(ring_buffer, ahead, data) \
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({ __auto_type rb = &(ring_buffer); \
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rb->buffer[(rb->tail + ahead) % RB_buffer_size (rb)] = (data); \
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})
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#endif//__QF_ringbuffer_h
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