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1813661a61
Remove `export` pramgas from defs headers as it causes IWYU to believe that the definitions from the defs headers comes from main header, which is not what we really want.
72 lines
2.4 KiB
C
72 lines
2.4 KiB
C
// Specialized ring buffer. This is basically an array that wraps read/write
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// pointers around the memory region. It should be more efficient than the old
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// RBuffer which required memmove() calls to relocate read/write positions.
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//
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// The main purpose of RBuffer is simplify memory management when reading from
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// uv_stream_t instances:
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//
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// - The event loop writes data to a RBuffer, advancing the write pointer
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// - The main loop reads data, advancing the read pointer
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// - If the buffer becomes full(size == capacity) the rstream is temporarily
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// stopped(automatic backpressure handling)
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//
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// Reference: http://en.wikipedia.org/wiki/Circular_buffer
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#pragma once
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#include <stddef.h>
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#include <stdint.h>
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#include "nvim/rbuffer_defs.h" // IWYU pragma: keep
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// Macros that simplify working with the read/write pointers directly by hiding
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// ring buffer wrap logic. Some examples:
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//
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// - Pass the write pointer to a function(write_data) that incrementally
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// produces data, returning the number of bytes actually written to the
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// ring buffer:
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//
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// RBUFFER_UNTIL_FULL(rbuf, ptr, cnt)
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// rbuffer_produced(rbuf, write_data(state, ptr, cnt));
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//
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// - Pass the read pointer to a function(read_data) that incrementally
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// consumes data, returning the number of bytes actually read from the
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// ring buffer:
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//
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// RBUFFER_UNTIL_EMPTY(rbuf, ptr, cnt)
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// rbuffer_consumed(rbuf, read_data(state, ptr, cnt));
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//
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// Note that the rbuffer_{produced,consumed} calls are necessary or these macros
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// create infinite loops
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#define RBUFFER_UNTIL_EMPTY(buf, rptr, rcnt) \
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for (size_t rcnt = 0, _r = 1; _r; _r = 0) \
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for (char *rptr = rbuffer_read_ptr(buf, &rcnt); \
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buf->size; \
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rptr = rbuffer_read_ptr(buf, &rcnt))
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#define RBUFFER_UNTIL_FULL(buf, wptr, wcnt) \
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for (size_t wcnt = 0, _r = 1; _r; _r = 0) \
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for (char *wptr = rbuffer_write_ptr(buf, &wcnt); \
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rbuffer_space(buf); \
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wptr = rbuffer_write_ptr(buf, &wcnt))
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// Iteration
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#define RBUFFER_EACH(buf, c, i) \
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for (size_t i = 0; \
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i < buf->size; \
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i = buf->size) \
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for (char c = 0; \
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i < buf->size ? ((int)(c = *rbuffer_get(buf, i))) || 1 : 0; \
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i++)
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#define RBUFFER_EACH_REVERSE(buf, c, i) \
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for (size_t i = buf->size; \
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i != SIZE_MAX; \
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i = SIZE_MAX) \
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for (char c = 0; \
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i-- > 0 ? ((int)(c = *rbuffer_get(buf, i))) || 1 : 0; \
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)
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#ifdef INCLUDE_GENERATED_DECLARATIONS
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# include "rbuffer.h.generated.h"
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#endif
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