将 C 指针代码示例转换为 Delphi 指针语法
我正在使用二进制文件结构。读取数据的代码示例是C语言的，我需要在Delphi中读取它。我赶紧补充一下，我没有 C 编程经验。
鉴于以下
typedef struct {
uchar ID, DataSource;
ushort ChecksumOffset;
uchar Spare, NDataTypes;
ushort Offset [256];
} HeaderType;
...
typedef struct {
ushort ID;
...
ushort DistanceToBin1Middle,TransmitLength;
} FixLeaderType;
...
HeaderType *HdrPtr;
FixLeaderType *FLdrPtr;
unsigned char RcvBuff[8192];
void DecodeBBensemble( void )
{
unsigned short i, *IDptr, ID;
FLdrPtr = (FixLeaderType *)&RcvBuff [ HdrPtr->Offset[0] ];
if (FLdrPtr->NBins > 128)
FLdrPtr->NBins = 32;
...
情况，我遇到的困难是：
FLdrPtr = (FixLeaderType *)&RcvBuff [ HdrPtr->Offset[0] ];
根据我的了解，[ HdrPtr->Offset[0] ]; 将返回第一个 Offset 数组项的值HdrPtr 指向的 HeaderType 结构？那么相当于 HdrPtr^.Offset[0] 吗？
那么 &RcvBuff [ HdrPtr->Offset[0] ]; 应该返回包含索引的 RcvBuff 数组项的值的内存地址，因此相当于 @RecBuff[HdrPtr^。偏移量[0]]？
然后我迷失了 (FixLeaderType *).. 。有人可以帮助准确解释 FldrPtr 引用的内容吗？
I am working with a binary file structure. The code example for reading the data is in C, and I need to read it in Delphi. I hasten to add I have no C programming experience.
Given the following
typedef struct {
uchar ID, DataSource;
ushort ChecksumOffset;
uchar Spare, NDataTypes;
ushort Offset [256];
} HeaderType;
...
typedef struct {
ushort ID;
...
ushort DistanceToBin1Middle,TransmitLength;
} FixLeaderType;
...
HeaderType *HdrPtr;
FixLeaderType *FLdrPtr;
unsigned char RcvBuff[8192];
void DecodeBBensemble( void )
{
unsigned short i, *IDptr, ID;
FLdrPtr = (FixLeaderType *)&RcvBuff [ HdrPtr->Offset[0] ];
if (FLdrPtr->NBins > 128)
FLdrPtr->NBins = 32;
...
The bit I am having difficulty following is this:
FLdrPtr = (FixLeaderType *)&RcvBuff [ HdrPtr->Offset[0] ];
From the little I understand, [ HdrPtr->Offset[0] ]; would be returning the value of the first Offset array item from the HeaderType struct pointed to by HdrPtr? So equivalent to HdrPtr^.Offset[0] ?
Then &RcvBuff [ HdrPtr->Offset[0] ]; should be returning the memory address containing the value of the RcvBuff array item indexed, so equivalent to @RecBuff[HdrPtr^.Offset[0]] ?
Then I get lost with (FixLeaderType *).. . Could someone please help explain exactly what is being referenced by FldrPtr ?
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相关代码位是
FldPtr的类型为FixLeaderType *或指向FixLeaderType的指针。RcvBuff是一个char数组。HdrPtr->Offset[0]解析为 ushort 值，因此RcvBuff [ HdrPtr->Offset[0] ]生成char价值。&表示不获取char的值，而是返回该值的地址。请注意，这意味着它是char *类型。char *类型是分配给FldPtr的错误类型。(FixLeaderType *)转换类型以使其有效。这称为强制转换操作。The bits of code that are relevant are
FldPtris of typeFixLeaderType *, or pointer toFixLeaderType.RcvBuffis an array ofchar.HdrPtr->Offset[0]resolves to an ushort value, soRcvBuff [ HdrPtr->Offset[0] ]yields acharvalue.&means that instead of getting the value of thecharthe address of the value is returned. Note that this means that it is of typechar *.char *type is the wrong type to assign toFldPtr. The(FixLeaderType *)converts the type so that it is valid. This is called a cast operation.我认为你应该阅读以下内容：
这让事情变得容易多了
i think you should read those like:
that makes things a lot easier