统计波形图波峰波谷大于某个幅度的数目

- (void)updateWithYValue:(CGFloat)newY {
    
    if (!isnan(newY)) {

        if (!_shouldResetConfiguration) {
            _minValue = newY;
            _maxValue = newY;
            _startValue = NO;
            _didCheckerFindingTarget = NO;
            _shouldResetConfiguration = YES;
        } else {
            if (!_didCheckerFindingTarget) {
                _maxValue = MAX(_maxValue, newY);
                _minValue = MIN(_minValue, newY);
                CGFloat gapFromMaxValue = (ABS(_maxValue - newY));
                CGFloat gapFromMinValue = (ABS(newY - _minValue));
                if (gapFromMaxValue >= self.minDistanceChangeForAllowRecordNumber) {
                    _didCheckerFindingTarget = YES;
                    _findingTopValue = NO;
                    _criticalValue = newY;
                    _maxValue = newY;
                    _foundTargetCount = 1;
                } else if (gapFromMinValue >= self.minDistanceChangeForAllowRecordNumber) {
                    _didCheckerFindingTarget = YES;
                    _findingTopValue = YES;
                    _criticalValue = newY;
                    _minValue = newY;
                    _foundTargetCount = 1;
                }
            } else {
                if (_findingTopValue) {
                    if (newY >= _criticalValue) {
                        _maxValue = MAX(newY, _maxValue);
                        _minValue = newY;
                        CGFloat gapFromMaxValue = (ABS(_maxValue - newY));
                        if (gapFromMaxValue >= self.minDistanceChangeForAllowRecordNumber) {
                            _criticalValue = newY;
                            _findingTopValue = NO;
                            if (_foundTargetCount % 2 == 0) {
                                [self addOneChangeCount];
                            }
                        }
                    } else {
                        CGFloat gapFromMaxValue = (ABS(_maxValue - newY));
                        _minValue  = MIN(_minValue, newY);
                        CGFloat gapFromMinValue = (ABS(newY - _minValue));
                        if (gapFromMaxValue >= self.minDistanceChangeForAllowRecordNumber) {
                            _foundTargetCount += 1;
                            _criticalValue = newY;
                            _minValue = newY;
                            _findingTopValue = NO;
                            if (_foundTargetCount % 2 == 0) {
                                [self addOneChangeCount];
                                printf("==============>2
");
                            }
                        } else if (gapFromMinValue >= self.minDistanceChangeForAllowRecordNumber) {
                            ///异常，需要忽略一半波形
                            _criticalValue = newY;
                            _maxValue = newY;
                            _findingTopValue = YES;
                        }
                    }
                } else {
                    if (newY <= _criticalValue) {
                        _minValue = MIN(newY, _minValue);
                        _maxValue = newY;
                        CGFloat gapFromMinValue = (ABS(newY - _minValue));
                        if (gapFromMinValue >= self.minDistanceChangeForAllowRecordNumber) {
                            _foundTargetCount += 1;
                            _criticalValue = newY;
                            _findingTopValue = YES;
                            if (_foundTargetCount % 2 == 0) {
                                [self addOneChangeCount];
                            }
                        }
                    } else {
                        CGFloat gapFromMinValue = (ABS(newY - _minValue));
                        _maxValue  = MAX(_maxValue, newY);
                        CGFloat gapFromMaxValue = (ABS(_maxValue - newY));
                        if (gapFromMinValue >= self.minDistanceChangeForAllowRecordNumber) {
                            _foundTargetCount += 1;
                            _criticalValue = newY;
                            _maxValue = newY;
                            _findingTopValue = YES;
                            if (_foundTargetCount % 2 == 0) {
                                [self addOneChangeCount];
                            }
                        } else if (gapFromMaxValue >= self.minDistanceChangeForAllowRecordNumber) {
                            ///异常，需要忽略一半波形
                            _criticalValue = newY;
                            _minValue = newY;
                            _findingTopValue = NO;
                        }
                    }
                }
            }
        }
    }
}

假设第一个点为最低值，根据下一个点判断趋势，记录探测接下来的值，记录max和min，当当前点达到触发临界差值，认定触发了一个波峰/波谷。若为波峰，保留最高值，探测下面的值，当探测到最高点到当前点差值到达临界值认为下到一个波谷，计数加1。