MentOS
0.8.0
The Mentoring Operating System
libc
inc
ring_buffer.h
Go to the documentation of this file.
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#pragma once
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#define DECLARE_FIXED_SIZE_RING_BUFFER(type, name, length, init) \
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typedef struct fs_rb_##name##_t { \
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unsigned size, read, write; \
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type buffer[length]; \
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} fs_rb_##name##_t; \
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static inline void fs_rb_##name##_init(fs_rb_##name##_t *rb) \
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{ \
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rb->size = length; \
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rb->read = rb->write = 0; \
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char *dst = (char *)rb->buffer; \
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long num = sizeof(type) * length; \
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while (num--) *dst++ = (char)(init & 0xFF); \
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} \
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static inline unsigned fs_rb_##name##_step(fs_rb_##name##_t *rb, unsigned index) \
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{ \
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return (index == (rb->size - 1)) ? 0 : index + 1; \
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} \
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static inline void fs_rb_##name##_push_front(fs_rb_##name##_t *rb, type item) \
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{ \
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if (fs_rb_##name##_step(rb, rb->write) == rb->read) \
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rb->read = fs_rb_##name##_step(rb, rb->read); \
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rb->buffer[rb->write] = item; \
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rb->write = fs_rb_##name##_step(rb, rb->write); \
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} \
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static inline type fs_rb_##name##_empty(fs_rb_##name##_t *rb) \
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{ \
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return rb->write == rb->read; \
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} \
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static inline type fs_rb_##name##_pop_back(fs_rb_##name##_t *rb) \
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{ \
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type item = init; \
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if (!fs_rb_##name##_empty(rb)) { \
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item = rb->buffer[rb->read]; \
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rb->read = fs_rb_##name##_step(rb, rb->read); \
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} \
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return item; \
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} \
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static inline type fs_rb_##name##_pop_front(fs_rb_##name##_t *rb) \
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{ \
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if (fs_rb_##name##_empty(rb)) \
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return init; \
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rb->write = (rb->write > 0) ? rb->write - 1 : rb->size - 1; \
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return rb->buffer[rb->write]; \
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} \
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static inline type fs_rb_##name##_get(fs_rb_##name##_t *rb, unsigned index) \
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{ \
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if (index < rb->size) \
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return rb->buffer[index]; \
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return init; \
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} \
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static inline type fs_rb_##name##_back(fs_rb_##name##_t *rb) \
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{ \
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if (fs_rb_##name##_empty(rb)) \
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return init; \
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return rb->buffer[rb->read]; \
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} \
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static inline type fs_rb_##name##_front(fs_rb_##name##_t *rb) \
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{ \
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if (fs_rb_##name##_empty(rb)) \
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return init; \
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return rb->buffer[(rb->write > 0) ? rb->write - 1 : rb->size - 1]; \
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}
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#ifdef __KERNEL__
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#define RING_BUFFER_ALLOC kmalloc
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#define RING_BUFFER_FREE kfree
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#else
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#define RING_BUFFER_ALLOC malloc
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#define RING_BUFFER_FREE free
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#endif
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#define DECLARE_RING_BUFFER(type, name, init) \
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typedef struct rb_##name##_t { \
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const unsigned size; \
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unsigned read, write; \
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type *buffer; \
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} rb_##name##_t; \
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static inline rb_##name##_t alloc_rb_##name(unsigned len) \
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{ \
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rb_##name##_t rb = { len, 0U, 0U, len > 0 ? RING_BUFFER_ALLOC(sizeof(type) * len) : NULL }; \
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memset(rb.buffer, init, sizeof(type) * len); \
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return rb; \
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} \
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static inline void free_rb_##name(rb_##name##_t *rb) \
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{ \
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RING_BUFFER_FREE(rb->buffer); \
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} \
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static inline unsigned step_rb_##name(rb_##name##_t *rb, unsigned index) \
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{ \
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return (index == (rb->size - 1)) ? 0 : index + 1; \
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} \
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static inline void push_rb_##name(rb_##name##_t *rb, type item) \
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{ \
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if (step_rb_##name(rb, rb->write) == rb->read) \
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rb->read = step_rb_##name(rb, rb->read); \
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rb->buffer[rb->write] = item; \
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rb->write = step_rb_##name(rb, rb->write); \
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} \
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static inline void pop_rb_##name(rb_##name##_t *rb, type *item) \
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{ \
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*item = init; \
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if (rb->write != rb->read) { \
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*item = rb->buffer[rb->read]; \
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rb->read = step_rb_##name(rb, rb->read); \
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} \
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} \
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static inline void get_rb_##name(rb_##name##_t *rb, unsigned index, type *item) \
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{ \
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if (index < rb->size) \
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*item = rb->buffer[index]; \
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}
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#undef RING_BUFFER_ALLOC
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#undef RING_BUFFER_FREE
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