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282 lines
19 KiB
C
282 lines
19 KiB
C
/// Macros-based ring buffer implementation.
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///
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/// Supported functions:
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///
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/// - new: allocates new ring buffer.
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/// - dealloc: free ring buffer itself.
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/// - free: free ring buffer and all its elements.
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/// - push: adds element to the end of the buffer.
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/// - length: get buffer length.
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/// - size: size of the ring buffer.
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/// - idx: get element at given index.
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/// - idx_p: get pointer to the element at given index.
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/// - insert: insert element at given position.
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/// - remove: remove element from given position.
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#ifndef NVIM_LIB_RINGBUF_H
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#define NVIM_LIB_RINGBUF_H
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#include <string.h>
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#include <assert.h>
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#include <stdint.h>
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#include "nvim/memory.h"
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#include "nvim/func_attr.h"
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#define _RINGBUF_LENGTH(rb) \
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((rb)->first == NULL ? 0 \
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: ((rb)->next == (rb)->first) ? (size_t) ((rb)->buf_end - (rb)->buf) + 1 \
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: ((rb)->next > (rb)->first) ? (size_t) ((rb)->next - (rb)->first) \
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: (size_t) ((rb)->next - (rb)->buf + (rb)->buf_end - (rb)->first + 1))
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#define _RINGBUF_NEXT(rb, var) \
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((var) == (rb)->buf_end ? (rb)->buf : (var) + 1)
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#define _RINGBUF_PREV(rb, var) \
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((var) == (rb)->buf ? (rb)->buf_end : (var) - 1)
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/// Iterate over all ringbuf values
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///
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/// @param rb Ring buffer to iterate over.
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/// @param RBType Type of the ring buffer element.
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/// @param varname Variable name.
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#define RINGBUF_FORALL(rb, RBType, varname) \
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size_t varname##_length_fa_ = _RINGBUF_LENGTH(rb); \
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for (RBType *varname = ((rb)->first == NULL ? (rb)->next : (rb)->first); \
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varname##_length_fa_; \
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(varname = _RINGBUF_NEXT(rb, varname)), \
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varname##_length_fa_--)
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/// Iterate over all ringbuf values, from end to the beginning
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///
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/// Unlike previous RINGBUF_FORALL uses already defined variable, in place of
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/// defining variable in the cycle body.
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///
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/// @param rb Ring buffer to iterate over.
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/// @param RBType Type of the ring buffer element.
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/// @param varname Variable name.
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#define RINGBUF_ITER_BACK(rb, RBType, varname) \
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size_t varname##_length_ib_ = _RINGBUF_LENGTH(rb); \
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for (varname = ((rb)->next == (rb)->buf ? (rb)->buf_end : (rb)->next - 1); \
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varname##_length_ib_; \
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(varname = _RINGBUF_PREV(rb, varname)), \
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varname##_length_ib_--)
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/// Define a ring buffer structure
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///
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/// @param TypeName Ring buffer type name. Actual type name will be
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/// `{TypeName}RingBuffer`.
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/// @param RBType Type of the single ring buffer element.
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#define RINGBUF_TYPEDEF(TypeName, RBType) \
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typedef struct { \
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RBType *buf; \
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RBType *next; \
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RBType *first; \
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RBType *buf_end; \
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} TypeName##RingBuffer;
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/// Initialize a new ring buffer
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///
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/// @param TypeName Ring buffer type name. Actual type name will be
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/// `{TypeName}RingBuffer`.
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/// @param funcprefix Prefix for all ring buffer functions. Function name will
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/// look like `{funcprefix}_rb_{function_name}`.
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/// @param RBType Type of the single ring buffer element.
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/// @param rbfree Function used to free ring buffer element. May be
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/// a macros like `#define RBFREE(item)` (to skip freeing).
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///
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/// Intended function signature: `void *rbfree(RBType *)`;
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#define RINGBUF_INIT(TypeName, funcprefix, RBType, rbfree) \
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\
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\
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static inline TypeName##RingBuffer funcprefix##_rb_new(const size_t size) \
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REAL_FATTR_WARN_UNUSED_RESULT; \
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static inline TypeName##RingBuffer funcprefix##_rb_new(const size_t size) \
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{ \
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assert(size != 0); \
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RBType *buf = xmalloc(size * sizeof(RBType)); \
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return (TypeName##RingBuffer) { \
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.buf = buf, \
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.next = buf, \
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.first = NULL, \
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.buf_end = buf + size - 1, \
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}; \
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} \
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\
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static inline void funcprefix##_rb_free(TypeName##RingBuffer *const rb) \
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REAL_FATTR_UNUSED; \
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static inline void funcprefix##_rb_free(TypeName##RingBuffer *const rb) \
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{ \
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if (rb == NULL) { \
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return; \
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} \
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RINGBUF_FORALL(rb, RBType, rbitem) { \
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rbfree(rbitem); \
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} \
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xfree(rb->buf); \
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} \
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\
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static inline void funcprefix##_rb_dealloc(TypeName##RingBuffer *const rb) \
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REAL_FATTR_UNUSED; \
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static inline void funcprefix##_rb_dealloc(TypeName##RingBuffer *const rb) \
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{ \
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xfree(rb->buf); \
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} \
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\
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static inline void funcprefix##_rb_push(TypeName##RingBuffer *const rb, \
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RBType item) \
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REAL_FATTR_NONNULL_ARG(1); \
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static inline void funcprefix##_rb_push(TypeName##RingBuffer *const rb, \
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RBType item) \
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{ \
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if (rb->next == rb->first) { \
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rbfree(rb->first); \
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rb->first = _RINGBUF_NEXT(rb, rb->first); \
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} else if (rb->first == NULL) { \
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rb->first = rb->next; \
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} \
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*rb->next = item; \
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rb->next = _RINGBUF_NEXT(rb, rb->next); \
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} \
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\
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static inline ptrdiff_t funcprefix##_rb_find_idx( \
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const TypeName##RingBuffer *const rb, const RBType *const item_p) \
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REAL_FATTR_NONNULL_ALL REAL_FATTR_PURE REAL_FATTR_UNUSED; \
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static inline ptrdiff_t funcprefix##_rb_find_idx( \
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const TypeName##RingBuffer *const rb, const RBType *const item_p) \
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{ \
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assert(rb->buf <= item_p); \
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assert(rb->buf_end >= item_p); \
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if (rb->first == NULL) { \
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return -1; \
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} else if (item_p >= rb->first) { \
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return item_p - rb->first; \
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} else { \
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return item_p - rb->buf + rb->buf_end - rb->first + 1; \
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} \
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} \
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\
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static inline size_t funcprefix##_rb_size( \
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const TypeName##RingBuffer *const rb) \
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REAL_FATTR_NONNULL_ALL REAL_FATTR_PURE; \
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static inline size_t funcprefix##_rb_size( \
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const TypeName##RingBuffer *const rb) \
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{ \
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return (size_t) (rb->buf_end - rb->buf) + 1; \
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} \
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\
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static inline size_t funcprefix##_rb_length( \
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const TypeName##RingBuffer *const rb) \
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REAL_FATTR_NONNULL_ALL REAL_FATTR_PURE; \
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static inline size_t funcprefix##_rb_length( \
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const TypeName##RingBuffer *const rb) \
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{ \
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return _RINGBUF_LENGTH(rb); \
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} \
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\
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static inline RBType *funcprefix##_rb_idx_p( \
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const TypeName##RingBuffer *const rb, const size_t idx) \
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REAL_FATTR_NONNULL_ALL REAL_FATTR_PURE; \
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static inline RBType *funcprefix##_rb_idx_p( \
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const TypeName##RingBuffer *const rb, const size_t idx) \
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{ \
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assert(idx <= funcprefix##_rb_size(rb)); \
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assert(idx <= funcprefix##_rb_length(rb)); \
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if (rb->first + idx > rb->buf_end) { \
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return rb->buf + ((rb->first + idx) - (rb->buf_end + 1)); \
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} else { \
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return rb->first + idx; \
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} \
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} \
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\
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static inline RBType funcprefix##_rb_idx(const TypeName##RingBuffer *const rb, \
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const size_t idx) \
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REAL_FATTR_NONNULL_ALL REAL_FATTR_PURE REAL_FATTR_UNUSED; \
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static inline RBType funcprefix##_rb_idx(const TypeName##RingBuffer *const rb, \
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const size_t idx) \
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{ \
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return *funcprefix##_rb_idx_p(rb, idx); \
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} \
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\
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static inline void funcprefix##_rb_insert(TypeName##RingBuffer *const rb, \
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const size_t idx, \
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RBType item) \
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REAL_FATTR_NONNULL_ARG(1) REAL_FATTR_UNUSED; \
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static inline void funcprefix##_rb_insert(TypeName##RingBuffer *const rb, \
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const size_t idx, \
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RBType item) \
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{ \
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assert(idx <= funcprefix##_rb_size(rb)); \
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assert(idx <= funcprefix##_rb_length(rb)); \
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const size_t length = funcprefix##_rb_length(rb); \
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if (idx == length) { \
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funcprefix##_rb_push(rb, item); \
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return; \
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} \
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RBType *const insertpos = funcprefix##_rb_idx_p(rb, idx); \
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if (insertpos == rb->next) { \
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funcprefix##_rb_push(rb, item); \
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return; \
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} \
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if (length == funcprefix##_rb_size(rb)) { \
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rbfree(rb->first); \
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} \
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if (insertpos < rb->next) { \
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memmove(insertpos + 1, insertpos, \
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(size_t) ((uintptr_t) rb->next - (uintptr_t) insertpos)); \
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} else { \
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assert(insertpos > rb->first); \
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assert(rb->next <= rb->first); \
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memmove(rb->buf + 1, rb->buf, \
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(size_t) ((uintptr_t) rb->next - (uintptr_t) rb->buf)); \
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*rb->buf = *rb->buf_end; \
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memmove(insertpos + 1, insertpos, \
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(size_t) ((uintptr_t) (rb->buf_end + 1) - (uintptr_t) insertpos)); \
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} \
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*insertpos = item; \
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if (length == funcprefix##_rb_size(rb)) { \
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rb->first = _RINGBUF_NEXT(rb, rb->first); \
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} \
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rb->next = _RINGBUF_NEXT(rb, rb->next); \
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} \
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\
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static inline void funcprefix##_rb_remove(TypeName##RingBuffer *const rb, \
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const size_t idx) \
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REAL_FATTR_NONNULL_ARG(1) REAL_FATTR_UNUSED; \
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static inline void funcprefix##_rb_remove(TypeName##RingBuffer *const rb, \
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const size_t idx) \
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{ \
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assert(idx < funcprefix##_rb_size(rb)); \
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assert(idx < funcprefix##_rb_length(rb)); \
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RBType *const rmpos = funcprefix##_rb_idx_p(rb, idx); \
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rbfree(rmpos); \
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if (rmpos == rb->next - 1) { \
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rb->next--; \
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if (rb->first == rb->next) { \
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rb->first = NULL; \
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rb->next = rb->buf; \
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} \
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} else if (rmpos == rb->first) { \
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rb->first = _RINGBUF_NEXT(rb, rb->first); \
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if (rb->first == rb->next) { \
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rb->first = NULL; \
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rb->next = rb->buf; \
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} \
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} else if (rb->first < rb->next || rb->next == rb->buf) { \
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assert(rmpos > rb->first); \
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assert(rmpos <= _RINGBUF_PREV(rb, rb->next)); \
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memmove(rb->first + 1, rb->first, \
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(size_t) ((uintptr_t) rmpos - (uintptr_t) rb->first)); \
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rb->first = _RINGBUF_NEXT(rb, rb->first); \
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} else if (rmpos < rb->next) { \
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memmove(rmpos, rmpos + 1, \
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(size_t) ((uintptr_t) rb->next - (uintptr_t) rmpos)); \
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rb->next = _RINGBUF_PREV(rb, rb->next); \
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} else { \
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assert(rb->first < rb->buf_end); \
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memmove(rb->first + 1, rb->first, \
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(size_t) ((uintptr_t) rmpos - (uintptr_t) rb->first)); \
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rb->first = _RINGBUF_NEXT(rb, rb->first); \
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} \
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}
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#endif // NVIM_LIB_RINGBUF_H
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