90 lines
2.0 KiB
C
90 lines
2.0 KiB
C
#include "ringbuffer.h"
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RB_BITS _rb_mod(RB_BITS num, RB_BITS denom)
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{
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for (; num >= denom; num -= denom);
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return num;
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}
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void ringbuffer_init(ringbuffer *buf, RB_BITS bufsize)
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{
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buf->read_pointer = 0;
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buf->write_pointer = 0;
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buf->size = bufsize - sizeof(ringbuffer);
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}
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RB_BITS ringbuffer_canread(ringbuffer *buf)
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{
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return _rb_mod(buf->size + buf->write_pointer - buf->read_pointer, buf->size);
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}
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RB_BITS ringbuffer_canwrite(ringbuffer *buf)
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{
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return _rb_mod(buf->size + buf->size + buf->read_pointer - buf->write_pointer - 1, buf->size);
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}
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uint8_t ringbuffer_readchar(ringbuffer *buf)
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{
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uint8_t r = 0;
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if (ringbuffer_canread(buf))
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{
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r = buf->data[buf->read_pointer];
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buf->read_pointer = _rb_mod(buf->read_pointer + 1, buf->size);
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}
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return r;
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}
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void ringbuffer_writechar(ringbuffer *buf, uint8_t data)
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{
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if (ringbuffer_canwrite(buf))
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{
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buf->data[buf->write_pointer] = data;
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buf->write_pointer = _rb_mod(buf->write_pointer + 1, buf->size);
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}
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}
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uint8_t ringbuffer_peekchar(ringbuffer *buf, RB_BITS index)
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{
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return buf->data[_rb_mod(buf->read_pointer + index, buf->size)];
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}
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RB_BITS ringbuffer_readblock(ringbuffer *buf, uint8_t *newbuf, RB_BITS size)
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{
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RB_BITS nc, i;
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uint8_t *rp, *ms;
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if ((nc = ringbuffer_canread(buf)) < size)
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size = nc;
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if (size)
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{
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for (i = 0, rp = ((uint8_t *) buf->data + buf->read_pointer), ms = ((uint8_t *) buf->data + buf->size); i < size; i++, rp++)
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{
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if (rp >= ms)
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rp = (uint8_t *) buf->data;
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newbuf[i] = *rp;
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}
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buf->read_pointer = rp - buf->data;
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}
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return size;
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}
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RB_BITS ringbuffer_writeblock(ringbuffer *buf, uint8_t *data, RB_BITS size)
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{
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RB_BITS nc, i;
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uint8_t *wp, *ms;
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if ((nc = ringbuffer_canwrite(buf)) < size)
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size = nc;
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if (size)
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{
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for (i = 0, wp = (uint8_t *) (buf->write_pointer + buf->data), ms = (uint8_t *) (buf->data + buf->size); i < size; i++, wp++)
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{
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if (wp >= ms)
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wp = (uint8_t *) buf->data;
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*wp = data[i];
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}
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buf->write_pointer = wp - buf->data;
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}
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return size;
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}
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