169 lines
3.4 KiB
C
169 lines
3.4 KiB
C
#include "fifo.h"
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#define MIN(a, b) (((a) < (b)) ? (a) : (b))
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fifo_error_t fifo_create( fifo_t *fifo , uint8_t *buffer, uint32_t size )
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{
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/* 参数检查 */
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if( (fifo == 0) || (buffer == 0) || (size == 0) )
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{
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return FIFO_ERROR_NULL;
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}
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/* 长度检查 (必须是2^n) */
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if( size & (size - 1) )
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{
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return FIFO_ERROR_LENGTH;
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}
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/* 默认 */
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fifo->size = size;
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fifo->buffer = buffer;
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fifo->in = 0;
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fifo->out = 0;
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return FIFO_OK;
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}
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fifo_error_t fifo_clear( fifo_t *fifo )
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{
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/* 参数检查 */
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if( fifo == 0 )
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{
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return FIFO_ERROR_NULL;
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}
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fifo->in = 0;
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fifo->out = 0;
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return FIFO_OK;
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}
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fifo_error_t fifo_write( fifo_t *fifo, uint8_t *buffer, uint32_t length )
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{
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uint32_t i, j;
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uint32_t end_length, org_length;
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uint8_t *fifo_buffer;
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/* 记录原始用户写入长度 */
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org_length = length;
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/* 计算FIFO剩余容量 */
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length = MIN( length, fifo->size - fifo->in + fifo->out );
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/* 计算FIFO缓存区末尾是否还有足够位置 */
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end_length = MIN( length, fifo->size - ( fifo->in & ( fifo->size - 1 ) ) );
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/* 找到FIFO可写入区域的起始地址 */
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fifo_buffer = fifo->buffer + ( fifo->in & ( fifo->size - 1 ) );
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/* 如果FIFO末尾有容量，则将用户数据复制到FIFO缓存区末尾 */
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for( i = 0; i < end_length; i++ )
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{
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*( fifo_buffer++ ) = *( buffer++ );
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}
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/* 计算用户数据是否已全部复制 */
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j = length - end_length;
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/* 如果用户数据有剩余，则需要从FIFO缓存区头部开始复制*/
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if ( j > 0 )
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{
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fifo_buffer = fifo->buffer;
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for( i = 0; i < j; i++ )
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{
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*( fifo_buffer++ ) = *( buffer++ );
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}
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}
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/* 记录已进入FIFO的长度 */
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fifo->in += length;
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/* 如果进入FIFO数据的长度小于用户实际写入数据的长度，那就是FIFO满了装不下了 */
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if( length < org_length )
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{
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return FIFO_ERROR_FULL;
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}
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return FIFO_OK;
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}
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fifo_error_t fifo_read( fifo_t *fifo, uint8_t *buffer, uint32_t length )
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{
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uint32_t i, j;
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uint32_t end_length, org_length;
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uint8_t *fifo_buffer;
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/* 记录原始用户读取长度 */
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org_length = length;
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/* 计算FIFO已入队数据长度 */
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length = MIN( length, fifo->in - fifo->out );
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/* 计算FIFO末尾出队长度 */
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end_length = MIN( length, fifo->size - ( fifo->out & ( fifo->size - 1 ) ) );
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/* 找到FIFO末尾出队区域的起始地址 */
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fifo_buffer = fifo->buffer + ( fifo->out & ( fifo->size - 1 ) );
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/* 如果FIFO末尾有数据出队，则从FIFO内复制给用户数据缓存 */
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for( i = 0; i < end_length; i++ )
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{
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*( buffer++ ) = *( fifo_buffer++ );
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}
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/* 计算用户数据是否已全部复制 */
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j = length - end_length;
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/* 如果用户数据有剩余，则需要从FIFO缓存区头部开始复制*/
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if ( j > 0 )
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{
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fifo_buffer = fifo->buffer;
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for( i = 0; i < j; i++ )
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{
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*( buffer++ ) = *( fifo_buffer++ ) ;
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}
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}
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/* 记录已出队的长度 */
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fifo->out += length;
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/* 如果FIFO出队数据长度小于用户实际需要数据的长度，那就是FIFO空了数量不够 */
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if( length < org_length )
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{
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return FIFO_ERROR_EMPTY;
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}
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return FIFO_OK;
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}
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fifo_error_t fifo_get_length( fifo_t *fifo , uint32_t *length)
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{
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if( (fifo==0) || (length==0) )
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{
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return FIFO_ERROR_NULL;
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}
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*length = fifo->in - fifo->out;
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return FIFO_OK;
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}
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fifo_error_t fifo_get_remain_length( fifo_t *fifo , uint32_t *length)
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{
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if( (fifo==0) || (length==0) )
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{
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return FIFO_ERROR_NULL;
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}
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*length = fifo->size - ( fifo->in - fifo->out );
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return FIFO_OK;
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}
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