/* * Copyright (c) 2006-2021, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2021-08-14 Jackistang add comments for function interface. */ #ifndef RINGBUFFER_H__ #define RINGBUFFER_H__ #ifdef __cplusplus extern "C" { #endif #include /* ring buffer */ struct rt_ringbuffer { rt_uint8_t *buffer_ptr; /* use the msb of the {read,write}_index as mirror bit. You can see this as * if the buffer adds a virtual mirror and the pointers point either to the * normal or to the mirrored buffer. If the write_index has the same value * with the read_index, but in a different mirror, the buffer is full. * While if the write_index and the read_index are the same and within the * same mirror, the buffer is empty. The ASCII art of the ringbuffer is: * * mirror = 0 mirror = 1 * +---+---+---+---+---+---+---+|+~~~+~~~+~~~+~~~+~~~+~~~+~~~+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 ||| 0 | 1 | 2 | 3 | 4 | 5 | 6 | Full * +---+---+---+---+---+---+---+|+~~~+~~~+~~~+~~~+~~~+~~~+~~~+ * read_idx-^ write_idx-^ * * +---+---+---+---+---+---+---+|+~~~+~~~+~~~+~~~+~~~+~~~+~~~+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 ||| 0 | 1 | 2 | 3 | 4 | 5 | 6 | Empty * +---+---+---+---+---+---+---+|+~~~+~~~+~~~+~~~+~~~+~~~+~~~+ * read_idx-^ ^-write_idx */ rt_uint32_t read_mirror : 1; rt_uint32_t read_index : 31; rt_uint32_t write_mirror : 1; rt_uint32_t write_index : 31; /* as we use msb of index as mirror bit, the size should be signed and * could only be positive. */ rt_int32_t buffer_size; }; enum rt_ringbuffer_state { RT_RINGBUFFER_EMPTY, RT_RINGBUFFER_FULL, /* half full is neither full nor empty */ RT_RINGBUFFER_HALFFULL, }; /** * RingBuffer for DeviceDriver * * Please note that the ring buffer implementation of RT-Thread * has no thread wait or resume feature. */ void rt_ringbuffer_init(struct rt_ringbuffer *rb, rt_uint8_t *pool, rt_int32_t size); void rt_ringbuffer_reset(struct rt_ringbuffer *rb); rt_size_t rt_ringbuffer_put(struct rt_ringbuffer *rb, const rt_uint8_t *ptr, rt_uint32_t length); rt_size_t rt_ringbuffer_put_force(struct rt_ringbuffer *rb, const rt_uint8_t *ptr, rt_uint32_t length); rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb, const rt_uint8_t ch); rt_size_t rt_ringbuffer_putchar_force(struct rt_ringbuffer *rb, const rt_uint8_t ch); rt_size_t rt_ringbuffer_get(struct rt_ringbuffer *rb, rt_uint8_t *ptr, rt_uint32_t length); rt_size_t rt_ringbuffer_peek(struct rt_ringbuffer *rb, rt_uint8_t **ptr); rt_size_t rt_ringbuffer_getchar(struct rt_ringbuffer *rb, rt_uint8_t *ch); rt_size_t rt_ringbuffer_data_len(struct rt_ringbuffer *rb); #ifdef RT_USING_HEAP struct rt_ringbuffer* rt_ringbuffer_create(rt_uint32_t length); void rt_ringbuffer_destroy(struct rt_ringbuffer *rb); #endif /** * @brief Get the buffer size of the ring buffer object. * * @param rb A pointer to the ring buffer object. * * @return Buffer size. */ rt_inline rt_uint32_t rt_ringbuffer_get_size(struct rt_ringbuffer *rb) { RT_ASSERT(rb != RT_NULL); return rb->buffer_size; } /** return the size of empty space in rb */ #define rt_ringbuffer_space_len(rb) ((rb)->buffer_size - rt_ringbuffer_data_len(rb)) #ifdef __cplusplus } #endif #endif