mirror of https://github.com/rene-dev/stmbl.git
115 lines
2.2 KiB
C
115 lines
2.2 KiB
C
#pragma once
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/**
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* Ringbuffer structure
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*
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*/
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struct ringbuf {
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char *buf; ///< Pointer to buffer memory
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unsigned bufsize; ///< Size of buffer memory
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volatile unsigned pos; ///< Current read position
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volatile unsigned len; ///< Length of data in buffer
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};
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/**
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* Read a single byte from a buffer
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*
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* \param rb pointer to ringbuffer struct
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* \param data pointer to data byte
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* \return number of bytes read (0 if buffer was empty)
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*/
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static inline int rb_getc(struct ringbuf *rb, char *data)
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{
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if (!rb->len)
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return 0;
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*data = rb->buf[rb->pos++];
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if (rb->pos >= rb->bufsize)
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rb->pos -= rb->bufsize;
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rb->len--;
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return 1;
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}
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/**
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* Write a single byte to a buffer
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*
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* \param rb pointer to ringbuffer struct
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* \param data pointer to data byte
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* \return number of bytes written (0 if buffer was full)
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*/
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static inline int rb_putc(struct ringbuf *rb, const char data)
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{
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if (rb->len >= rb->bufsize)
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return 0;
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unsigned i = rb->pos + rb->len;
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if (i >= rb->bufsize)
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i -= rb->bufsize;
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rb->buf[i] = data;
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rb->len++;
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return 1;
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}
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#if 0
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/**
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* Read from a buffer
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*
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*/
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int rb_read(struct ringbuf *rb, void *data, int len)
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{
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if (len > rb->len)
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len = rb->len;
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int len1 = len;
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if (rb->pos + len1 >= rb->bufsize) {
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int len2 = (rb->pos + len1) - rb->bufsize;
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len1 -= len2;
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memcpy((char*)data + len1, rb->buf, len2);
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}
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memcpy(data, rb->buf + rb->pos, len1);
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rb->len -= len;
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rb->pos += len;
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if (rb->pos > rb->bufsize)
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rb->pos -= rb->bufsize;
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return len;
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}
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/**
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* Write to a buffer
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*
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* \param rb pointer to ringbuffer struct
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* \param data pointer to data byte
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* \return number of bytes written (0 if buffer was full)
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*
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*/
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int rb_write(struct ringbuf *rb, const void *data, int len)
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{
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if (len > rb->bufsize - rb->len)
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len = rb->bufsize - rb->len;
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int len1 = len;
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if (rb->pos + rb->len + len1 >= rb->bufsize) {
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int len2 = (rb->pos + rb->len + len1) - rb->bufsize;
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len1 -= len2;
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memcpy(rb->buf, (char*)data + len1, len2);
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}
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memcpy(rb->buf + rb->pos + rb->len, data, len1);
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rb->len += len;
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return len;
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}
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#endif
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