在研究stm32f407的I2S时发现有几个函数是官方写的，但是在手册和官方文档中没有找到出处，请官方能否忙里偷闲加入这部分内容，我将此部分源码贴出来请官方获知：
/** * Audio Memory Node Manage */struct rt_data_node{ char *data_ptr; rt_uint32_t data_size;};struct rt_data_node_list{ struct rt_data_node *node; rt_uint32_t size; rt_uint32_t read_index, write_index; rt_uint32_t data_offset; void (*read_complete)(struct rt_data_node *node, void *user_data); void *user_data;};int rt_data_node_init(struct rt_data_node_list **node_list, rt_uint32_t size){ int result = RT_EOK; struct rt_data_node_list *list = RT_NULL; struct rt_data_node *node = RT_NULL; list = rt_malloc(sizeof(struct rt_data_node_list)); if (list == RT_NULL) { result = -RT_ENOMEM; goto __exit; } memset(list, 0, sizeof(struct rt_data_node_list)); node = rt_malloc(sizeof(struct rt_data_node) * size); if (size == RT_NULL) { result = -RT_ENOMEM; goto __exit; } memset(node, 0, sizeof(struct rt_data_node)); list->node = node; list->size = size; list->read_index = 0; list->write_index = 0; list->data_offset = 0; list->read_complete = RT_NULL; list->user_data = 0; *node_list = list; return result;__exit: if (list) rt_free(list); if (node) rt_free(node); return result;}int rt_data_node_is_empty(struct rt_data_node_list *node_list){ rt_uint32_t read_index, write_index; rt_base_t level; level = rt_hw_interrupt_disable(); read_index = node_list->read_index; write_index = node_list->write_index; rt_hw_interrupt_enable(level); if (read_index == write_index) { return RT_TRUE; } else { return RT_FALSE; }}void wait_node_free(struct rt_data_node_list *node_list){ while (node_list->read_index != node_list->write_index) rt_thread_mdelay(5);}int rt_data_node_write(struct rt_data_node_list *node_list, void *buffer, rt_uint32_t size){ struct rt_data_node *node = RT_NULL; rt_uint32_t read_index, write_index, next_index; rt_base_t level; level = rt_hw_interrupt_disable(); read_index = node_list->read_index; write_index = node_list->write_index; rt_hw_interrupt_enable(level); next_index = write_index + 1; if (next_index >= node_list->size) next_index = 0; if (next_index == read_index) { rt_kprintf("[node]:node list full, write index = %d, read index = %d <br>", write_index, read_index); return -RT_ERROR; } level = rt_hw_interrupt_disable(); /* set node attribute */ node = &node_list->node[write_index]; node->data_ptr = (char *) buffer; node->data_size = size; node_list->write_index = next_index; rt_hw_interrupt_enable(level); return size;}int rt_data_node_read(struct rt_data_node_list *node_list, void *buffer, rt_uint32_t size){ struct rt_data_node *node = RT_NULL; rt_uint32_t read_index, write_index, next_index; rt_int32_t remain_len, copy_size; rt_uint32_t read_offset, data_offset; rt_base_t level; rt_uint32_t result = size; level = rt_hw_interrupt_disable(); read_index = node_list->read_index; write_index = node_list->write_index; rt_hw_interrupt_enable(level); read_offset = 0; if (read_index == write_index) { result = 0; } else { do { node = &node_list->node[node_list->read_index]; data_offset = node_list->data_offset; remain_len = node->data_size - data_offset; if (size - read_offset > remain_len) { /* Full*/ copy_size = remain_len; } else { /* reamain buffer */ copy_size = size - read_offset; } memcpy((char *)buffer + read_offset, node->data_ptr + data_offset, copy_size); read_offset += copy_size; data_offset += copy_size; node_list->data_offset = data_offset; if (data_offset >= node->data_size) { /* notify transmitted complete. */ if (node_list->read_complete != RT_NULL) { node_list->read_complete(node, node_list->user_data); } level = rt_hw_interrupt_disable(); read_index = node_list->read_index; write_index = node_list->write_index; rt_hw_interrupt_enable(level); next_index = read_index + 1; if (next_index >= node_list->size) next_index = 0; level = rt_hw_interrupt_disable(); node_list->read_index = next_index; node_list->data_offset = 0; rt_hw_interrupt_enable(level); if (next_index == write_index) { result = read_offset; break; } } } while (read_offset < size); } return result;}static void data_node_read_complete(struct rt_data_node *node, void *user_data){ struct rt_device *dev = RT_NULL; dev = (struct rt_device *)user_data; if (dev->tx_complete != RT_NULL) { dev->tx_complete(dev, node->data_ptr); }}
