ab545f83b0
The functions in `cib.h` are only used in `msg.c`. They are very small, and proper function calls have a bigger overhead than inlining these functions. The difference in .text size (worst to best): ``` +104 native +69 qemu-i386 +32 mbed_lpc1768 +28 samr21-xpro -54 chronos -54 z1 -56 iot-lab_M3 -56 msb-430 -56 msb-430h -56 msba2 -56 openmote -56 spark-core -56 telosb -56 wsn430-v1_3b -56 wsn430-v1_4 -58 arduino-mega2560 -60 airfy-beacon -60 arduino-due -60 f4vi1 -60 msbiot -60 pca10000 -60 pca10005 -60 stm32f0discovery -60 stm32f3discovery -60 stm32f4discovery -60 udoo -60 yunjia-nrf51822 -72 avsextrem -72 pttu -120 redbee-econotag ```
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
/*
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* Copyright (C) 2013 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @addtogroup core_util
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* @{
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*
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* @file cib.h
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* @brief Circular integer buffer interface
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* @details This structure provides an organizational interface
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* and combined with an memory array forms a circular buffer.
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*
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* @author unknown, propably Kaspar Schleiser <kaspar@schleiser.de>
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*/
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#ifndef __CIB_H
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#define __CIB_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief circular integer buffer structure
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*/
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typedef struct {
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unsigned int read_count; /**< number of (successful) read accesses */
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unsigned int write_count; /**< number of (successful) write accesses */
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unsigned int mask; /**< Size of buffer -1, i.e. mask of the bits */
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} cib_t;
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#define CIB_INIT(SIZE) ((cib_t) { 0, 0, (SIZE) - 1 })
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/**
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* @brief Initialize cib_t to 0 and set size.
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*
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* @param[out] cib Buffer to initialize.
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* Must not be NULL.
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* @param[in] size Size of the buffer.
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*/
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static inline void cib_init(cib_t *restrict cib, unsigned int size)
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{
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*cib = CIB_INIT(size);
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}
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/**
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* @brief Calculates difference between cib_put() and cib_get() accesses.
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*
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* @param[in] cib the cib_t to check.
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* Must not be NULL.
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* @return How often cib_get() can be called before the CIB is empty.
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*/
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static inline unsigned int cib_avail(cib_t *restrict cib)
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{
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return cib->write_count - cib->read_count;
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}
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/**
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* @brief Get the index of the next item in buffer.
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*
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* @param[in,out] cib corresponding *cib* to buffer.
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* Must not be NULL.
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* @return index of next item, -1 if the buffer is empty
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*/
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static inline int cib_get(cib_t *restrict cib)
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{
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unsigned int avail = cib_avail(cib);
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if (avail > 0) {
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return (int) (cib->read_count++ & cib->mask);
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}
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return -1;
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}
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/**
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* @brief Get index for item in buffer to put to.
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*
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* @param[in,out] cib corresponding *cib* to buffer.
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* Must not be NULL.
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* @return index of item to put to, -1 if the buffer is full
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*/
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static inline int cib_put(cib_t *restrict cib)
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{
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unsigned int avail = cib_avail(cib);
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/* We use a signed compare, because the mask is -1u for an empty CIB. */
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if ((int) avail <= (int) cib->mask) {
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return (int) (cib->write_count++ & cib->mask);
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}
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return -1;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* __CIB_H */
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/** @} */
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