string.cpp

一本叫自己动手写嵌入式操作系统的书的源代码,作者是蓝枫叶,详细介绍了如何写一个嵌入式操作系统,而不是操作系统

//***********************************************************************/
//    Author                    : Garry
//    Original Date             : May,28 2004
//    Module Name               : string.cpp
//    Module Funciton           : 
//                                This module and string.h countains the
//                                string operation functions.
//    Last modified Author      :
//    Last modified Date        :
//    Last modified Content     :
//                                1.
//                                2.
//    Lines number              :
//***********************************************************************/

#ifndef __HELLO_CHINA__
#include "..\INCLUDE\StdAfx.h"
#endif

#ifndef __STRING__
#include "string.h"
#endif

//
//String operation functions implementation.
//
BOOL StrCmp(LPSTR strSrc,LPSTR strDes)  //Compare the two strings,if equal,returns
                                        //TRUE,otherwise,returns FALSE.
{
	BOOL bResult = FALSE;
	WORD wIndex = 0x0000;

	if((NULL == strSrc) || (NULL == strDes))  //Parameter check.
		return FALSE;

	while(strSrc[wIndex] && strDes[wIndex] && (strSrc[wIndex] == strDes[wIndex]))
	{
		wIndex ++;
	}

	return strSrc[wIndex] == strDes[wIndex] ? TRUE : FALSE;
}

WORD StrLen(LPSTR strSrc)        //Get the string's length.
                                 //If the string's lenght is less than 
								 //MAX_STRING_LEN,returns the actual string's
								 //length,otherwise,returns MAX_STRING_LEN.
{
	WORD wStrLen = 0x00;

	if(NULL == strSrc)
		return -1;

	while(strSrc[wStrLen] && (MAX_STRING_LEN > wStrLen))
		wStrLen ++;

	return wStrLen;
}

BOOL Hex2Str(DWORD dwSrc,LPSTR strBuffer)  //Convert the hex format to string.
{
	BOOL bResult = FALSE;
	BYTE bt = 0x00;
	
	if(NULL == strBuffer)        //Parameter check.
		return bResult;

	for(WORD i = 0;i < 8;i ++)
	{
		bt = LOBYTE(LOWORD(dwSrc));
		bt = bt & 0x0f;     //Get the low 4 bits.
		if(bt < 10)              //Should to convert to number.
		{
			bt += '0';
			strBuffer[7 - i] = bt;
		}
		else                     //Should to convert to character.
		{
			bt -= 10;
			bt += 'A';
			strBuffer[7 - i] = bt;
		}
		dwSrc = dwSrc >> 0x04;   //Continue to process the next 4 bits.
	}

	strBuffer[8] = 0x00;         //Add the string's terminal sign.
	return TRUE;
}

//
//Convert 32 bit int number to string.
//
BOOL Int2Str(DWORD dwNum,LPSTR pszResult)
{
	BOOL bResult = FALSE;
	BYTE bt;
	BYTE index = 0;
	BYTE sw;

	if(NULL == pszResult)
		return bResult;

	do{
		bt =  BYTE(dwNum % 10);
		bt += '0';
		pszResult[index++] = bt;
		dwNum /= 10;
	}while(dwNum);
	pszResult[index] = 0;        //Set the terminal sign.
	
	for(bt = 0;bt < index/2;bt ++)  //Inverse the string.
	{
		sw = pszResult[bt];
		pszResult[bt] = pszResult[index - bt -1];
		pszResult[index - bt - 1] = sw;
	}

	bResult = TRUE;
	return bResult;
}

//
//Print a string at a new line.
//
VOID PrintLine(LPSTR pszStr)
{
	GotoHome();
	ChangeLine();
	PrintStr(pszStr);
}

//
//Copy the first string, to the second string buffer.
//
VOID StrCpy(LPSTR strSrc,LPSTR strDes)
{
	if((NULL == strSrc) || (NULL == strDes))  //Parameter check.
		return;

	DWORD dwIndex = 0;
	
	while(strSrc[dwIndex])
	{
		strDes[dwIndex] = strSrc[dwIndex];
		dwIndex ++;
	}
	strDes[dwIndex] = 0;
}

//
//Convert the string's low character to uper character.
//Such as,the input string is "abcdefg",then,the output
//string would be "ABCDEFG".
//

VOID ConvertToUper(LPSTR pszSource)
{
	BYTE     bt        = 'a' - 'A';
	DWORD    dwIndex   = 0x0000;
	DWORD    dwMaxLen  = MAX_STRING_LEN;

	if(NULL == pszSource)
		return;

	while(*pszSource)
	{
		if((*pszSource >= 'a') && ( *pszSource <= 'z'))
		{
			*pszSource -= bt;
		}
		pszSource ++;
		dwMaxLen --;
		if(0 == dwMaxLen)
			break;
	}

	return;
}

//
//Convert the string to hex number.
//If success,it returns TRUE,else,returns FALSE.
//
BOOL Str2Hex(LPSTR pszSrc,DWORD* pdwResult)
{
	BOOL     bResult  = FALSE;
	DWORD    dwResult = 0x00000000;
	if((NULL == pszSrc) || (NULL == pdwResult))  //Parameters check.
		return bResult;

	if(StrLen(pszSrc) > 8)                      //If the string's length is longer
		                                        //than the max hex number length.
		return bResult;

	ConvertToUper(pszSrc);                      //Convert to uper character.

	while(*pszSrc)
	{
		dwResult <<= 4;
		switch(*pszSrc)
		{
		case '0':
			dwResult += 0;
			break;
		case '1':
			dwResult += 1;
			break;
		case '2':
			dwResult += 2;
			break;
		case '3':
			dwResult += 3;
			break;
		case '4':
			dwResult += 4;
			break;
		case '5':
			dwResult += 5;
			break;
		case '6':
			dwResult += 6;
			break;
		case '7':
			dwResult += 7;
			break;
		case '8':
			dwResult += 8;
			break;
		case '9':
			dwResult += 9;
			break;
		case 'A':
			dwResult += 10;
			break;
		case 'B':
			dwResult += 11;
			break;
		case 'C':
			dwResult += 12;
			break;
		case 'D':
			dwResult += 13;
			break;
		case 'E':
			dwResult += 14;
			break;
		case 'F':
			dwResult += 15;
			break;
		default:
			bResult = FALSE;
			return bResult;
		}
		pszSrc ++;
	}

	bResult    = TRUE;
	*pdwResult = dwResult;

	return bResult;
}

//
//The implementation of FormString routine.
//This routine formats a string,and copy it into a buffer.
//It's function likes sprintf.
//
INT FormString(LPSTR lpszBuff,LPSTR lpszFmt,LPVOID* lppParam)
{
	DWORD        dwIndex        = 0L;
	LPSTR        lpszTmp        = NULL;
	BYTE         Buff[12];

	if((NULL == lpszBuff) || (NULL == lpszBuff))
		return -1;

	lpszTmp = lpszBuff;
	while(*lpszFmt)
	{
		if('%' == *lpszFmt)    //Should process.
		{
			lpszFmt ++;        //Skip '%'.
			switch(*lpszFmt)
			{
			case 'd':    //Convert an integer to string.
				Int2Str(*((DWORD*)lppParam[dwIndex ++]),Buff);  //Convert to string.
				StrCpy(Buff,lpszTmp);
				lpszTmp += StrLen(Buff);
				lpszFmt ++;
				break;
			case 'c':    //Convert a character to string.
				*lpszTmp ++= *((BYTE*)lppParam[dwIndex ++]);
				lpszFmt ++;
				break;
			case 's':    //Append a string.
				StrCpy((LPSTR)lppParam[dwIndex],lpszTmp);
				lpszTmp += StrLen((LPSTR)lppParam[dwIndex ++]);
				lpszFmt ++;
				break;
			case 'x':    //Convert an integer to string in hex.
			case 'X':
				Hex2Str(*((DWORD*)lppParam[dwIndex ++]),Buff);  //Convert to string.
				StrCpy(Buff,lpszTmp);
				lpszTmp += StrLen(Buff);
				lpszFmt ++;
				break;
			default:     //Unsupported now.
				break;
			}
		}
		*lpszTmp = *lpszFmt;
		if(0 == *lpszTmp)    //Reach end.
			break;
		lpszTmp ++;
		lpszFmt ++;
	}

	*lpszTmp = 0;    //End sign.
	return (lpszTmp - lpszBuff);
}