The open source OpenXR runtime
util: Add a index fifo
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doc/changes/auxiliary/mr.359.1.md
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doc/changes/auxiliary/mr.359.1.md
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src/xrt/auxiliary/util/u_index_fifo.h
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src/xrt/auxiliary/util/u_index_fifo.h
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// Copyright 2020, Collabora, Ltd.
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// SPDX-License-Identifier: BSL-1.0
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/*!
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* @file
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* @brief A FIFO for indices.
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* @author Jakob Bornecrantz <jakob@collabora.com>
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* @ingroup aux_util
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*/
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#pragma once
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#define U_MAX_FIFO_INDICES 16
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struct u_index_fifo
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{
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uint32_t indices[U_MAX_FIFO_INDICES];
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size_t start;
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size_t end;
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};
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static inline int
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u_index_fifo_is_empty(struct u_index_fifo *uif)
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{
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if (uif->start == uif->end) {
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return 1;
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} else {
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return 0;
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}
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}
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static inline int
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u_index_fifo_is_full(struct u_index_fifo *uif)
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{
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if (((uif->end + 1) % U_MAX_FIFO_INDICES) == uif->start) {
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return 1;
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} else {
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return 0;
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}
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}
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static inline int
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u_index_fifo_peek(struct u_index_fifo *uif, uint32_t *out_index)
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{
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if (u_index_fifo_is_empty(uif)) {
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return -1;
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}
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*out_index = uif->indices[uif->start];
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return 0;
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}
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static inline int
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u_index_fifo_pop(struct u_index_fifo *uif, uint32_t *out_index)
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{
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if (u_index_fifo_is_empty(uif)) {
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return -1;
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}
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*out_index = uif->indices[uif->start];
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uif->start = (uif->start + 1) % U_MAX_FIFO_INDICES;
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return 0;
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}
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static inline int
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u_index_fifo_push(struct u_index_fifo *uif, uint32_t index)
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{
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if (u_index_fifo_is_full(uif)) {
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return -1;
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}
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uif->indices[uif->end] = index;
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uif->end = (uif->end + 1) % U_MAX_FIFO_INDICES;
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return 0;
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}