创建从.las二进制文件读取的指针会引发bad_alloc错误

Question

我目前正在编写代码以读取.las(LIDAR点数据(文件。在读取文件后，我创建了一个指针来遍历所有点。然而，它给了我一个严重的错误。

我唯一能想到的是，标头的大小与las文件标头指定的大小不同。我仔细检查了标头，没有发现任何错误。

header和PointRecord3中的所有标头变量分别来自本文档第3页和第10页。

更新：读入的点数为402673112。然而，当我在其他激光雷达软件中打开它进行双重检查时，点数只有5104152。我相信这是因为我在用C++打开云之前，在其他软件中过滤了云，从而减少了点数。

这是我的代码：

#ifndef POINTCLOUD_H
#define POINTCLOUD_H
#pragma once
#include <string>

class PointCloud
{
public:
PointCloud(const std::string &path);
private:
struct __attribute__((packed)) Header {
char magic[4];
uint16_t fileourceID;
uint16_t globalEncoding;
uint32_t guiData1;
uint16_t guiData2;
uint16_t guiData3;
uint8_t guiData[8];
uint8_t versionMaj, versionMin;
char systemIdentifer[32];
char genSoftware[32];
uint16_t creationDay, creationYear;
uint16_t headerSize;
uint32_t pointDataOffset;
uint32_t numVarLenRecords;
uint8_t pointDataRecordFormat;
uint16_t pointDataRecordLen;
uint32_t numberOfPoints;
uint32_t numPointsByReturn[5];
double scaleX, scaleY, scaleZ;
double offX, offY, offZ;
double minX, minY, minZ;
double maxX, maxY, maxZ;
};
struct __attribute__((packed)) PointRecord3 {
uint32_t X, Y, Z;
uint16_t intensity;
uint8_t flags;
uint8_t classification;
uint8_t scanAngleRank;
uint8_t userData;
uint16_t pointSourceID;
double gpsTime;
uint16_t red;
uint16_t green;
uint16_t blue;
}; 

#include "PointCloud.h"
#include <fstream>
#include <iostream>
#include <string>
#include <assert.h>
using namespace std;
PointCloud::PointCloud(const string &path)
{
read(path);
}
void PointCloud::read(const string &path) {
ifstream in(path.c_str(), ios::binary );
if(in.is_open()){
Header header;
in.read((char *)&header, sizeof(header));
assert(header.versionMaj == 1 && header.versionMin == 2);
cout << "headerSize " << header.headerSize << " == " << sizeof(header) << " size of header struct" <<endl;
cout << "FILE TYPE: LAS " << (int)header.versionMaj << "." << (int)header.versionMin << endl;
cout << "POINT DATA OFFSET: " << (int)header.pointDataOffset <<endl;
cout << "POINT DATA RECORD FORMAT: " << (int)header.pointDataRecordFormat <<endl;
cout << "NUMBER OF POINTS: " << (int)header.numberOfPoints << endl;

PointRecord3 *points = new PointRecord3[header.numberOfPoints];
in.seekg(header.pointDataOffset);
for(uint32_t i = 0; i < header.numberOfPoints; i++) {
in.read((char *) (points + i), sizeof(*points));
}
if(in.good()) {
throw runtime_error("error");
}
delete points;

} else {
cout << "file not opened" << endl;
}
}

任何帮助都将不胜感激，谢谢！

这里还有LAS文件头的输出：

file signature:             'LASF'
file source ID:             0
global_encoding:            0
project ID GUID data 1-4:   00000000-0000-0000-0000-000000000000
version major.minor:        1.2
system identifier:          'EXPORT'
generating software:        'RiSCAN_PRO'
file creation day/year:     317/2018
header size:                227
offset to point data:       313
number var. length records: 1
point data format:          3
point data record length:   34
number of point records:    5104152
number of points by return: 5104152 0 0 0 0
scale factor x y z:         0.00025 0.00025 0.00025
offset x y z:               267805 3197054 13
min x y z:                  267804.25250 3196596.64500 -1.89000
max x y z:                  268760.27000 3197586.23000 23.33000
variable length header record 1 of 1:
reserved             43707
user ID              'LASF_Projection'
record ID            34735
length after header  32
description          'GeoKeyDirectoryTag (mandatory)'
GeoKeyDirectoryTag version 1.1.0 number of keys 3
key 1025 tiff_tag_location 0 count 1 value_offset 2 - GTRasterTypeGeoKey: RasterPixelIsPoint
key 1024 tiff_tag_location 0 count 1 value_offset 3 - GTModelTypeGeoKey: ModelTypeGeocentric
key 2048 tiff_tag_location 0 count 1 value_offset 4326 - GeographicTypeGeoKey: GCS_WGS_84
reporting minimum and maximum for all LAS point record entries ...
X               -2989    3821075
Y            -1829412    2128911
Z              -59559      41318
intensity       32767      32768
return_number       1          1
number_of_returns   1          1
edge_of_flight_line 0          0
scan_direction_flag 1          1
classification      0          0
scan_angle_rank     0          0
user_data           0          0
point_source_ID     0          0
gps_time 0.000000 0.000000
Color R 0 0
G 0 0
B 0 0
number of first returns:        5104152
number of intermediate returns: 0
number of last returns:         5104152
number of single returns:       5104152
overview over number of returns of given pulse: 5104152 0 0 0 0 0 0
histogram of classification of points:
5104152  never classified (0)

Answer 1

我想明白了。因此，C++添加了一些额外的字节，导致我的头结构比实际的文件头大5个字节。我通过添加#pragma包(push，1(解决了这个问题。

#ifndef POINTCLOUD_H
#define POINTCLOUD_H
#pragma pack (push, 1)
#include <string>

struct float3
{
float x, y, z;
};
class PointCloud
{
public:
PointCloud(const std::string &path);
private:
struct __attribute__((packed)) Header
{
char fileSig[4];
uint16_t fileourceID;
uint16_t globalEncoding;
uint32_t guiData1;
uint16_t guiData2;
uint16_t guiData3;
uint8_t guiData[8];
uint8_t versionMaj, versionMin;
char systemIdentifer[32];
char genSoftware[32];
uint16_t creationDay, creationYear;
uint16_t headerSize;
uint32_t pointDataOffset;
uint32_t numVarLenRecords;
uint8_t pointDataRecordFormat;
uint16_t pointDataRecordLen;
uint32_t numberOfPoints;
uint32_t numPointsByReturn[5];
double scaleX, scaleY, scaleZ;
double offX, offY, offZ;
double minX, minY, minZ;
double maxX, maxY, maxZ;
};
struct __attribute__((packed)) PointRecord3
{
uint32_t X, Y, Z;
uint16_t intensity;
uint8_t flags;
uint8_t classification;
uint8_t scanAngleRank;
uint8_t userData;
uint16_t pointSourceID;
double gpsTime;
uint16_t red;
uint16_t green;
uint16_t blue;
};

void read(const std::string &path);
};

#endif // POINTCLOUD_H