【OpenCV学习】yml的读取

#include <stdio.h>
#include "cxcore.h"
int main( int argc, char** argv )
{
    CvFileStorage* fs = cvOpenFileStorage( "points.yaml", 0, CV_STORAGE_READ );
        /*所有已读存储在文件元素的关键字被存储在hash表中，
    它使用哈希指针“x”和“y"加速对点的解析。这样可以加速查找操作 */
    CvStringHashNode* x_key = cvGetHashedKey( fs, "x", -1, 1 );
    CvStringHashNode* y_key = cvGetHashedKey( fs, "y", -1, 1 );
    CvFileNode* points = cvGetFileNodeByName( fs, 0, "points" );
    if( CV_NODE_IS_SEQ(points->tag) )
    {
        CvSeq* seq = points->data.seq;
        int i, total = seq->total;
        CvSeqReader reader;
        cvStartReadSeq( seq, &reader, 0 );
        for( i = 0; i < total; i++ )
        {
            CvFileNode* pt = (CvFileNode*)reader.ptr;
#if 1 /* 快变量 */
            CvFileNode* xnode = cvGetFileNode( fs, pt, x_key, 0 );
            CvFileNode* ynode = cvGetFileNode( fs, pt, y_key, 0 );
            assert( xnode && CV_NODE_IS_INT(xnode->tag) &&
                    ynode && CV_NODE_IS_INT(ynode->tag));
            int x = xnode->data.i; // or x = cvReadInt( xnode, 0 );
            int y = ynode->data.i; // or y = cvReadInt( ynode, 0 );
#elif 1 /* 慢变量：不使用x值与y值  */
            CvFileNode* xnode = cvGetFileNodeByName( fs, pt, "x" );
            CvFileNode* ynode = cvGetFileNodeByName( fs, pt, "y" );
            assert( xnode && CV_NODE_IS_INT(xnode->tag) &&
                    ynode && CV_NODE_IS_INT(ynode->tag));
            int x = xnode->data.i; // or x = cvReadInt( xnode, 0 );
            int y = ynode->data.i; // or y = cvReadInt( ynode, 0 );
#else /* 最慢的可以轻松使用的变量  */
            int x = cvReadIntByName( fs, pt, "x", 0 /* default value */ );
            int y = cvReadIntByName( fs, pt, "y", 0 /* default value */ );
#endif
            CV_NEXT_SEQ_ELEM( seq->elem_size, reader );
            printf("%d: (%d, %d)/n", i, x, y );
        }
    }
    cvReleaseFileStorage( &fs );
    return 0;
}