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- #ifndef _LIBMAPLE_RING_BUFFER_H_
- #define _LIBMAPLE_RING_BUFFER_H_
- typedef unsigned char u8; // 无符号8位整型变量
- typedef signed char int8; // 有符号8位整型变量
- typedef unsigned short u16; // 无符号16位整型变量
- typedef signed short int16; // 有符号16位整型变量
- typedef unsigned int u32; // 无符号32位整型变量
- typedef signed int int32; // 有符号32位整型变量
- #ifdef __cplusplus
- extern "C" {
- #endif
- /**
- * Ring buffer type.
- *
- * The buffer is empty when head == tail.
- *
- * The buffer is full when the head is one byte in front of the tail,
- * modulo buffer length.
- *
- * One byte is left free to distinguish empty from full. */
- typedef struct ring_buffer {
- volatile u8 *buf; /**< Buffer items are stored into */
- u16 head; /**< Index of the next item to remove */
- u16 tail; /**< Index where the next item will get inserted */
- u16 size; /**< Buffer capacity minus one */
- } ring_buffer;
- typedef struct ring_buffer16 {
- volatile u16 *buf; /**< Buffer items are stored into */
- u16 head; /**< Index of the next item to remove */
- u16 tail; /**< Index where the next item will get inserted */
- u16 size; /**< Buffer capacity minus one */
- } ring_buffer16;
- /**
- * Initialise a ring buffer.
- *
- * @param rb Instance to initialise
- *
- * @param size Number of items in buf. The ring buffer will always
- * leave one element unoccupied, so the maximum number of
- * elements it can store will be size - 1. Thus, size
- * must be at least 2.
- *
- * @param buf Buffer to store items into
- */
- static inline void rb_init(ring_buffer *rb, u16 size, u8 *buf) {
- rb->head = 0;
- rb->tail = 0;
- rb->size = size - 1;
- rb->buf = buf;
- }
- static inline void rb_init16(ring_buffer16 *rb, u16 size, u16 *buf) {
- rb->head = 0;
- rb->tail = 0;
- rb->size = size - 1;
- rb->buf = buf;
- }
- /**
- * @brief Return the number of elements stored in the ring buffer.
- * @param rb Buffer whose elements to count.
- */
- static inline u16 rb_full_count(ring_buffer *rb) {
- volatile ring_buffer *arb = rb;
- u32 size = arb->tail - arb->head;
- if (arb->tail < arb->head) {
- size += arb->size + 1;
- }
- return (u16)size;
- }
- static inline u16 rb_full_count16(ring_buffer16 *rb) {
- volatile ring_buffer16 *arb = rb;
- u32 size = arb->tail - arb->head;
- if (arb->tail < arb->head) {
- size += arb->size + 1;
- }
- return (u16)size;
- }
- /**
- * @brief Returns true if and only if the ring buffer is full.
- * @param rb Buffer to test.
- */
- static inline int rb_is_full(ring_buffer *rb) {
- return (rb->tail + 1 == rb->head) ||
- (rb->tail == rb->size && rb->head == 0);
- }
- static inline int rb_is_full16(ring_buffer16 *rb) {
- return (rb->tail + 1 == rb->head) ||
- (rb->tail == rb->size && rb->head == 0);
- }
- /**
- * @brief Returns true if and only if the ring buffer is empty.
- * @param rb Buffer to test.
- */
- static inline int rb_is_empty(ring_buffer *rb) {
- return rb->head == rb->tail;
- }
- static inline int rb_is_empty16(ring_buffer16 *rb) {
- return rb->head == rb->tail;
- }
- /**
- * Append element onto the end of a ring buffer.
- * @param rb Buffer to append onto.
- * @param element Value to append.
- */
- static inline void rb_insert(ring_buffer *rb, u8 element) {
- rb->buf[rb->tail] = element;
- rb->tail = (rb->tail == rb->size) ? 0 : rb->tail + 1;
- }
- static inline void rb_insert16(ring_buffer16 *rb, u16 element) {
- rb->buf[rb->tail] = element;
- rb->tail = (rb->tail == rb->size) ? 0 : rb->tail + 1;
- }
- /**
- * @brief Remove and return the first item from a ring buffer.
- * @param rb Buffer to remove from, must contain at least one element.
- */
- static inline u8 rb_remove(ring_buffer *rb) {
- u8 ch = rb->buf[rb->head];
- rb->head = (rb->head == rb->size) ? 0 : rb->head + 1;
- return ch;
- }
- static inline u16 rb_remove16(ring_buffer16 *rb) {
- u8 ch = rb->buf[rb->head];
- rb->head = (rb->head == rb->size) ? 0 : rb->head + 1;
- return ch;
- }
- static inline u8 rb_peek(ring_buffer *rb) {
- u8 ch = rb->buf[rb->head];
- return ch;
- }
- static inline u8 rb_peek_byCount(ring_buffer *rb,u8 str[]) {
- u8 x;
- x=0;
- if (rb->buf[rb->head]==0x7E && rb_full_count(rb)>rb->buf[rb->head+1])
- {
- for(int i=0; i<rb->buf[rb->head+1]; i++)
- {
- str[i] = rb->buf[rb->head+i];
- x++;
- }
- }
- return x;
- }
- static inline u16 rb_peek16(ring_buffer16 *rb) {
- u8 ch = rb->buf[rb->head];
- return ch;
- }
- /**
- * @brief Attempt to remove the first item from a ring buffer.
- *
- * If the ring buffer is nonempty, removes and returns its first item.
- * If it is empty, does nothing and returns a negative value.
- *
- * @param rb Buffer to attempt to remove from.
- */
- static inline int16 rb_safe_remove(ring_buffer *rb) {
- return rb_is_empty(rb) ? -1 : rb_remove(rb);
- }
- static inline int16 rb_safe_remove16(ring_buffer16 *rb) {
- return rb_is_empty16(rb) ? -1 : rb_remove16(rb);
- }
- /**
- * @brief Attempt to insert an element into a ring buffer.
- *
- * @param rb Buffer to insert into.
- * @param element Value to insert into rb.
- * @sideeffect If rb is not full, appends element onto buffer.
- * @return If element was appended, then true; otherwise, false. */
- static inline int rb_safe_insert(ring_buffer *rb, u8 element) {
- if (rb_is_full(rb)) {
- return 0;
- }
- rb_insert(rb, element);
- return 1;
- }
- static inline int rb_safe_insert16(ring_buffer16 *rb, u16 element) {
- if (rb_is_full16(rb)) {
- return 0;
- }
- rb_insert16(rb, element);
- return 1;
- }
- /**
- * @brief Append an item onto the end of a non-full ring buffer.
- *
- * If the buffer is full, removes its first item, then inserts the new
- * element at the end.
- *
- * @param rb Ring buffer to insert into.
- * @param element Value to insert into ring buffer.
- * @return On success, returns -1. If an element was popped, returns
- * the popped value.
- */
- static inline int rb_push_insert(ring_buffer *rb, u8 element) {
- int ret = -1;
- if (rb_is_full(rb)) {
- ret = rb_remove(rb);
- }
- rb_insert(rb, element);
- return ret;
- }
- static inline int rb_push_insert16(ring_buffer16 *rb, u16 element) {
- int ret = -1;
- if (rb_is_full16(rb)) {
- ret = rb_remove16(rb);
- }
- rb_insert16(rb, element);
- return ret;
- }
- /**
- * @brief Discard all items from a ring buffer.
- * @param rb Ring buffer to discard all items from.
- */
- static inline void rb_reset(ring_buffer *rb) {
- rb->tail = rb->head;
- }
- static inline void rb_reset16(ring_buffer16 *rb) {
- rb->tail = rb->head;
- }
- #ifdef __cplusplus
- } // extern "C"
- #endif
- #endif
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