用一维数组实现变长字符串

王朝other·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

经常看到在结构中定一个1维的数组,估计大多数人初看这种定义都要蒙一下,其实这是用结构实现变长字符串,是程序设计中一个很有意思的技巧

使用结构实现变长字符串可以很容易的控制字符串的结构,方便对字符串数据的操作。

试想一下,如果不用结构那么需要一位一位的计算每一个字符所在位置,不把你搞死才怪

废话少说,下面是一个例子,很简单的。

#pragma pach(push, 1)

struct SHORT_STRING

{

BYTE byStrLen;

char sString[1];

};

struct STRUCT_HEAD

{

BYTE byRelation;

bool bNotify;

};

struct STRUCT_HEAD_SAVE : STRUCT_HEAD

{

SHORT_STRING PartnerName;

};

struct STRUCT_SAVE_HEAD

{

WORD wCount;

BYTE byMsgTransmit;

};

#pragma pack(pop)

#define LOGIN_ROLE_NAME_MAX_LEN 32

#define SHORT_STRING_LEN(n) ((n) + 1)

#define STRUCT_HEAD_SAVE_LEN(n) (sizeof(STRUCT_HEAD) + SHORT_STRING_LEN(n))

int main()

{

int nCount = 10;

STRUCT_SAVE_HEAD* pSaveHead;

int nSize = sizeof(STRUCT_SAVE_HEAD) + (sizeof(STRUCT_HEAD_SAVE) + LOGIN_ROLE_NAME_MAX_LEN) * nCount;

pSaveHead = (STRUCT_SAVE_HEAD*)malloc(nSize);

int nOffset = sizeof(STRUCT_SAVE_HEAD);

pSaveHead->wCount = 0;

STRUCT_HEAD_SAVE* pRelation = (STRUCT_HEAD_SAVE*)(((char*)pSaveHead) + nOffset);

static char szName[][12] = {

"1",

"22",

"333",

"4444",

"55555",

"666666",

"7777777",

"88888888",

"999999999",

"0000000000"

};

for (int i=0; i<10; i++)

{

pRelation->byRelation = 1;

pRelation->bNotify = 1;

pRelation->PartnerName.byStrLen = strlen(szName[i]);

memcpy(pRelation->PartnerName.sString, szName[i], pRelation->PartnerName.byStrLen);

nOffset += STRUCT_HEAD_SAVE_LEN(pRelation->PartnerName.byStrLen);

pRelation = (STRUCT_HEAD_SAVE*)(((BYTE*)pSaveHead) + nOffset);

pSaveHead->wCount++;

}

STRUCT_SAVE_HEAD *head = (STRUCT_SAVE_HEAD*)pSaveHead;

nOffset = sizeof(STRUCT_SAVE_HEAD);

pRelation = (STRUCT_HEAD_SAVE*)(((char*)pSaveHead) + nOffset);

pRelation = (STRUCT_HEAD_SAVE*)&(pRelation->PartnerName.sString[pRelation->PartnerName.byStrLen]);

pRelation = (STRUCT_HEAD_SAVE*)&(pRelation->PartnerName.sString[pRelation->PartnerName.byStrLen]);

pRelation = (STRUCT_HEAD_SAVE*)&(pRelation->PartnerName.sString[pRelation->PartnerName.byStrLen]);

}

 
 
 
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