C++ 无法从流或字节读取结构
我正在尝试从文件中读取LAS文件1.3头 在我看到的每一个标题中,我首先要读的是格式签名,它总是“LASF” 当我试着读文件的时候,我看到的只是“我的”字 我知道头的大小是227,我甚至试着直接从文件中读取227的长度,但我仍然没有读取我应该读取的内容。我希望这是有道理的 这就是我尝试过的:C++ 无法从流或字节读取结构,c++,C++,我正在尝试从文件中读取LAS文件1.3头 在我看到的每一个标题中,我首先要读的是格式签名,它总是“LASF” 当我试着读文件的时候,我看到的只是“我的”字 我知道头的大小是227,我甚至试着直接从文件中读取227的长度,但我仍然没有读取我应该读取的内容。我希望这是有道理的 这就是我尝试过的: typedef struct Header { char File_Signature[4]; USHORT SourceID; USHORT Reserved1; UIN
typedef struct Header
{
char File_Signature[4];
USHORT SourceID;
USHORT Reserved1;
UINT GUID1;
USHORT GUID2;
USHORT GUID3;
char GUID4[8];
BYTE VersionMajor;
BYTE VersionMinor;
char SystemID[32];
char GeneratingSoftware[32];
USHORT DOY;
USHORT YEAR;
USHORT HeaderSize;
UINT PointOffset;
INT NumberOfVariableLengthRecords;
BYTE PointDataFormatID;
USHORT PointDataRecordLength;
INT NumberOfPointRecords;
UINT NumberofPointsByReturn1;
UINT NumberofPointsByReturn2;
UINT NumberofPointsByReturn3;
UINT NumberofPointsByReturn4;
UINT NumberofPointsByReturn5;
double XScaleFactor;
double YScaleFactor;
double ZScaleFactor;
double Xoffset;
double Yoffset;
double Zoffset;
double MaxX;
double MinX;
double MaxY;
double MinY;
double MaxZ;
double MinZ;
} LasHeader;
void OpenLasFile()
{
//THIS DOES NOT WORK
char buffer[227];
ifstream myFile ("C:\atlass\area_cov.las");
myFile.read (buffer, 227);
//NOT WORK, TRIED THIS TOO
ifstream input_file("C:\atlass\area_cov.las", ios::binary);
LasHeader header;
input_file.read((char*)&header, sizeof(header));
input_file.close();
//ALL DATA OUTPUT'ed ARE 'ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ'
}
这是我试图读取的文件中的一个二进制块
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
我的问题是:为什么我在读垃圾值,我做错了什么
--------------------更新--------------------------
我测试了这个,它工作了,所以读取文件一定有问题,有人能帮忙吗
起作用的是:
unsigned char rawData[552] =
{
0x4C, 0x41, 0x53, 0x46, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x02, 0x00, 0x03, 0x00,
0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x01, 0x02, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x73,
0x20, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x43, 0x6F, 0x72, 0x65, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x41, 0x74, 0x6C, 0x61, 0x73, 0x43,
0x6F, 0x72, 0x65, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x1E, 0x01, 0xDC, 0x07, 0xE3, 0x00,
0xE3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x1C, 0x00, 0x14, 0x01, 0x2F, 0x00, 0x14,
0x01, 0x2F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D, 0x62, 0x50, 0x3F, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D,
0x62, 0x50, 0x3F, 0xFC, 0xA9, 0xF1, 0xD2, 0x4D, 0x62, 0x50, 0x3F, 0x00, 0x00, 0x00, 0x00, 0xB0,
0x53, 0x20, 0x41, 0x00, 0x00, 0x00, 0x00, 0x24, 0xFF, 0x53, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0xE7, 0xB3, 0xFA, 0x83, 0x88, 0xA9, 0x20, 0x41, 0x1B, 0x56, 0x11, 0xE9, 0xBC,
0x1B, 0x20, 0x41, 0x77, 0x10, 0xD2, 0x7C, 0x27, 0x11, 0x54, 0x41, 0x14, 0xA5, 0xEC, 0x80, 0x7E,
0xF4, 0x53, 0x41, 0xC5, 0x20, 0xB0, 0x72, 0x68, 0x5D, 0x68, 0x40, 0x37, 0x89, 0x41, 0x60, 0xE5,
0xD0, 0x12, 0xC0, 0x21, 0xBE, 0x92, 0xFF, 0x06, 0x66, 0x17, 0x01, 0xA9, 0x60, 0x00, 0x00, 0xD8,
0x03, 0xC9, 0x02, 0xE2, 0x00, 0x01, 0x00, 0xAC, 0x71, 0x36, 0xBD, 0xE3, 0x25, 0x04, 0x41, 0x37,
0xB9, 0x92, 0xFF, 0x77, 0x58, 0x17, 0x01, 0xD7, 0x60, 0x00, 0x00, 0xE2, 0x0A, 0xC9, 0x02, 0xE2,
0x00, 0x01, 0x00, 0x4B, 0x90, 0x11, 0x90, 0xE3, 0x25, 0x04, 0x41, 0x00, 0xBF, 0x92, 0xFF, 0x98,
0x3A, 0x17, 0x01, 0x2B, 0x62, 0x00, 0x00, 0x23, 0x0A, 0x49, 0x02, 0xE4, 0x00, 0x01, 0x00, 0xBF,
0xF5, 0x61, 0xBD, 0xE3, 0x25, 0x04, 0x41, 0x1A, 0xBD, 0x92, 0xFF, 0x30, 0x11, 0x17, 0x01, 0xE4,
0x62, 0x00, 0x00, 0xDF, 0x08, 0x49, 0x02, 0xE4, 0x00, 0x01, 0x00, 0xF8, 0x6E, 0xF3, 0xA6, 0xE3,
0x25, 0x04, 0x41, 0x01, 0xBE, 0x92, 0xFF, 0x67, 0xE7, 0x16, 0x01, 0x83, 0x63, 0x00, 0x00, 0xCB,
0x06, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0x0B, 0xF3, 0x1E, 0xA7, 0xE3, 0x25, 0x04, 0x41, 0xF2,
0xBB, 0x92, 0xFF, 0x99, 0xD9, 0x16, 0x01, 0x6D, 0x63, 0x00, 0x00, 0x03, 0x09, 0x49, 0x02, 0xE5,
0x00, 0x01, 0x00, 0x82, 0x1C, 0x94, 0x90, 0xE3, 0x25, 0x04, 0x41, 0xFA, 0xBE, 0x92, 0xFF, 0x98,
0xBE, 0x16, 0x01, 0x13, 0x63, 0x00, 0x00, 0xFF, 0x08, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0xE5,
0xF0, 0x49, 0xA7, 0xE3, 0x25, 0x04, 0x41, 0xEE, 0xBC, 0x92, 0xFF, 0xDE, 0xB0, 0x16, 0x01, 0x04,
0x63, 0x00, 0x00, 0x8E, 0x0B, 0x49, 0x02, 0xE5, 0x00, 0x01, 0x00, 0x95, 0xA0, 0xBF, 0x90, 0xE3,
0x25, 0x04, 0x41, 0xD2, 0xBD, 0x92, 0xFF, 0x19, 0x88, 0x16, 0x01, 0xA9, 0x63, 0x00, 0x00, 0xD1,
0x08, 0x49, 0x02, 0xE7, 0x00, 0x01, 0x00, 0xA7, 0x24, 0xEB, 0x90, 0xE3, 0x25, 0x04, 0x41, 0xA8,
0xBE, 0x92, 0xFF, 0x29, 0x64, 0x16, 0x01, 0x97, 0x63, 0x00, 0x00, 0xFD, 0x04, 0x49, 0x02, 0xE7,
0x00, 0x01, 0x00, 0xC4, 0xF0, 0x11, 0x91, 0xE3, 0x25, 0x04, 0x41, 0x79, 0xD0, 0x92, 0xFF, 0xD0,
0x70, 0x17, 0x01, 0x30, 0x61, 0x00, 0x00, 0x60, 0x02, 0xC9, 0x02, 0xE2, 0x00, 0x01, 0x00, 0x91,
0x65, 0xC1, 0x44, 0xE4, 0x25, 0x04, 0x41, 0x12, 0xC7, 0x92, 0xFF, 0x02, 0x5E, 0x17, 0x01, 0x79,
0x61, 0x00, 0x00, 0x79, 0x05, 0xC9, 0x02, 0xE2,
} ;
LasHeader test;
memcpy(&test, rawData, sizeof(test));
问题在于:
ifstream myFile ("C:\atlass\area_cov.las");
反斜杠是C字符串中的一个特殊字符。在这种特殊情况下,\a
被a(0x0B
)替换,因此它试图打开错误的路径并失败
相反,您需要通过将路径中出现的所有反斜杠加倍来避开它们:
ifstream myFile ("C:\\atlass\\area_cov.las");
问题在于:
ifstream myFile ("C:\atlass\area_cov.las");
反斜杠是C字符串中的一个特殊字符。在这种特殊情况下,\a
被a(0x0B
)替换,因此它试图打开错误的路径并失败
相反,您需要通过将路径中出现的所有反斜杠加倍来避开它们:
ifstream myFile ("C:\\atlass\\area_cov.las");
谢谢,我检查过了,它似乎没有打开,为什么会这样?我试过这样做:myFile.open(“C:\atlass\area\u cov.las”);如果(myFile.is_open()){myFile.read(buffer,227);}我认为您应该添加
ios::in
:ifstream输入文件(“C:\atlass\area_cov.las”,ios::in | ios::binary)代码>你需要避开你的反斜杠<代码>“c:\\atlass\\area\u cov.las”
如果计划从文件中读取结构/类,可能需要检查编译器是否在任何结构/类成员变量之间添加填充字节。谢谢,我检查了它,但它似乎没有打开,为什么会这样?我试过这样做:myFile.open(“C:\atlass\area\u cov.las”);如果(myFile.is_open()){myFile.read(buffer,227);}我认为您应该添加ios::in
:ifstream输入文件(“C:\atlass\area_cov.las”,ios::in | ios::binary)代码>你需要避开你的反斜杠“c:\\atlass\\area\u cov.las”
如果计划从文件中读取结构/类,可能需要检查编译器是否在任何结构/类成员变量之间添加填充字节。