RT-Thread 环形缓冲区

#include "rb.h" enum rb_state { RINGBUFFER_EMPTY, RINGBUFFER_FULL, RINGBUFFER_HALFFULL, /* half full is neither full nor empty */ }; // 获取 ringbuff 的状态 enum rb_state rb_status(ringbuff *rb) { if (rb->read_index == rb->write_index) { if (rb->read_mirror == rb->write_mirror) return RINGBUFFER_EMPTY; else return RINGBUFFER_FULL; } return RINGBUFFER_HALFFULL; } // 获取 ringbuff 中数据的长度 uint16 rb_data_len(ringbuff *rb) { switch (rb_status(rb)) { case RINGBUFFER_EMPTY: return 0;//空就返回 0 case RINGBUFFER_FULL: return rb->size;// 满就返回缓冲区的大小 case RINGBUFFER_HALFFULL:// 半满 default: if (rb->write_index > rb->read_index) // 如果在同一镜像 return rb->write_index - rb->read_index; // 返回下标差 else return rb->size - (rb->read_index - rb->write_index); // 如果不在同一镜像，通过计算获取数据的长度 }; } // 缓冲区初始化 void rb_init(ringbuff *rb,uint8 *pool,uint16 size){ /* initialize read and write index */ rb->read_mirror = rb->read_index = 0; rb->write_mirror = rb->write_index = 0; /* set buffer pool and size */ rb->buffer_ptr = pool; rb->size = DATA_ALIGN_DOWN(size, DATA_ALIGN_SIZE); } // 创建一个ringbuff ringbuff* rb_create(uint16_t size) { ringbuff *rb; uint8_t *pool; size = DATA_ALIGN_DOWN(size, DATA_ALIGN_SIZE);// 大小做字节对齐 rb = (ringbuff *)malloc(sizeof(ringbuff));// 申请内存 if (rb == NULL) goto exit; pool = (uint8_t *)malloc(size);// 申请数据缓冲区内存 if (pool == NULL) { free(rb); rb = NULL; goto exit; } rb_init(rb, pool, size);// 初始化 ringbuff exit: return rb; } // 往 ringbuff 写入数据 uint16 rb_put(ringbuff *rb,const uint8 *ptr,uint16 length) { uint16 size = 0; /* whether has enough space */ size = rb_space_len(rb);// 获取 ring_buff 中可用空间的大小 /* no space */ if (size == 0) return 0;// 如果空间不够 直接返回 /* drop some data */ if (size < length) // 如果缓存区的空间不够保存这一次数据， 则把能够写入的这一部分数据写进去 length = size; /* One-time write */ if (rb->size - rb->write_index > length) { /* read_index - write_index = empty space */ memcpy(&rb->buffer_ptr[rb->write_index], ptr, length); /* this should not cause overflow because there is enough space for * length of data in current mirror */ rb->write_index += length; return length;// 返回写入数据的长度 } /* two-time write */ memcpy(&rb->buffer_ptr[rb->write_index], &ptr[0], rb->size - rb->write_index); memcpy(&rb->buffer_ptr[0], &ptr[rb->size - rb->write_index], length - (rb->size - rb->write_index)); /* we are going into the other side of the mirror */ rb->write_mirror = ~rb->write_mirror; rb->write_index = length - (rb->size - rb->write_index); return length; } // 强制往 ringbuff 写入数据 uint16 rb_put_force(ringbuff *rb,const uint8 *ptr,uint16 length) { uint16 space_length = 0; space_length = rb_space_len(rb); // cout<<"ptr: "<<ptr<<endl; // cout<<"space_length: "<<space_length<<endl; // cout<<"length: "<<length<<endl; if (length > space_length) { ptr = &ptr[length - rb->size]; length = rb->size; } // cout<<"ptr: "<<ptr<<endl; // cout<<"length: "<<length<<endl; if (rb->size - rb->write_index > length) { // cout<<"lailailailai"<<endl; /* read_index - write_index = empty space */ memcpy(&rb->buffer_ptr[rb->write_index], ptr, length); /* this should not cause overflow because there is enough space for * length of data in current mirror */ rb->write_index += length; if (length > space_length) rb->read_index = rb->write_index; return length; } memcpy(&rb->buffer_ptr[rb->write_index], &ptr[0], rb->size - rb->write_index); memcpy(&rb->buffer_ptr[0], &ptr[rb->size - rb->write_index], length - (rb->size - rb->write_index)); /* we are going into the other side of the mirror */ rb->write_mirror = ~rb->write_mirror; rb->write_index = length - (rb->size - rb->write_index); if (length > space_length) { rb->read_mirror = ~rb->read_mirror; rb->read_index = rb->write_index; } return length; } // 从 ringbuff 获取数据 uint16 rb_get(ringbuff *rb,uint8 *ptr,uint16 length) { uint16 size = 0; /* The length of the existing data in the buffer */ size = rb_data_len(rb); /* no data */ if (size == 0) return 0; /* less data */ if (size < length) length = size; cout<<"size: "<<size<<" < "<<"length: " << length<<(size < length)<<endl; if (rb->size - rb->read_index > length) { /* copy all of data */ memcpy(ptr, &rb->buffer_ptr[rb->read_index], length); /* this should not cause overflow because there is enough space for * length of data in current mirror */ rb->read_index += length; return length; } memcpy(&ptr[0], &rb->buffer_ptr[rb->read_index], rb->size - rb->read_index); memcpy(&ptr[rb->size - rb->read_index], &rb->buffer_ptr[0], length - (rb->size - rb->read_index)); /* we are going into the other side of the mirror */ rb->read_mirror = ~rb->read_mirror; rb->read_index = length - (rb->size - rb->read_index); return length; } // 往 ringbuff 中写入一个字符 uint16 rb_putchar(ringbuff *rb, const uint8 ch) { /* whether has enough space */ if (!rb_space_len(rb)) // 没有足够的空间就直接返回了 return 0; rb->buffer_ptr[rb->write_index] = ch;// 把这个字符写入到缓冲区的指定位置 /* flip mirror */ if (rb->write_index == rb->size-1) {// 检查写入这个字符后，当前镜像是否写满 rb->write_mirror = ~rb->write_mirror;// 翻转镜像 rb->write_index = 0;// 设置下标为0 }else{ rb->write_index++; // 下标加1 } return 1;// 写入一个字符，返回 1 } // 往 ringbuff 强制写入一个字符 uint16 rb_putchar_force(ringbuff *rb, const uint8 ch) { enum rb_state old_state = rb_status(rb);// 获取状态 rb->buffer_ptr[rb->write_index] = ch;// 写入数据 /* flip mirror */ if (rb->write_index == rb->size-1) {// 检查当前镜像是不是满了 rb->write_mirror = ~rb->write_mirror; // 翻转写镜像 rb->write_index = 0;// 翻转之后设置下标为 0 if (old_state == RINGBUFFER_FULL) {// 如果 ringbuff 的状态是满 rb->read_mirror = ~rb->read_mirror; // 翻转读镜像 rb->read_index = rb->write_index; // 设置读下标和写下标一致 } }else{ rb->write_index++; // 写下标加1 if (old_state == RINGBUFFER_FULL) rb->read_index = rb->write_index;// 如果满，设置读下标等于写下标 } return 1; // 写入一个字符，返回1 } // 从ringbuff 获取一个字符 uint16 rb_getchar(ringbuff *rb,uint8 *ch) { /* ringbuffer is empty */ if (!rb_data_len(rb)) // 检查 ringbuff 是否为空 return 0; /* put character */ *ch = rb->buffer_ptr[rb->read_index];// 获取当前读下标的数据 if (rb->read_index == rb->size-1) {// 如果