myutils.c

C语言源代码及相关资料

char	lowercase ( char c )
{
	if ( 'A' <= c && c <= 'Z' ) return (char)(c - 'A' + 'a');
	return c;
}

int		mystrcmpnocase ( char * p, char * q )
{
char	c;
char	d;	

	if ( p == 0 ) return -1;
	if ( q == 0 ) return  1;

	do {
		c = lowercase ( *p++ );
		d = lowercase ( *q++ );

		if ( c < d ) return -1;		//	include c == null char
		if ( c > d ) return  1;		//	include d == null char
	} while  ( c != '\0' || d != '\0' );

	return 0;
}

int		mystrncmpnocase ( char * p, char * q, int n )
{
char	c;
char	d;	

	if ( p == 0 ) return -1;
	if ( q == 0 ) return  1;

	do {
		c = lowercase ( *p++ );
		d = lowercase ( *q++ );

		if ( c < d ) return -1;		//	include c == null char
		if ( c > d ) return  1;		//	include d == null char

		if ( --n <= 0 ) break;
	} while  ( c != '\0' || d != '\0' );

	return 0;
}

/*
Purpose:
	get data of first field in string 'p',
	and store data into buffer 'pfield' with the size 'nbytes' + 1;
	nbytes for data space and plus one byte for NULL terminating char
Parameters:
	p:		target string to retrieve field data
	pfield:	buffer to store first field
	nbytes:	space size of pfield - 1 
Return:
	finally, return the pointer of first byte of the next field or 0, i.e. no field followed
*/
unsigned
char *	getfield ( unsigned char * p, unsigned char * pfield, int nbytes )
{
int		i;
char	c;

	if ( pfield == 0 ) return 0;	//	not valid spaces

	*pfield = '\0';

	if ( nbytes <= 0 ) return 0;	//	no spaces to store
	if ( p == 0      ) return 0;	//	nothing to do

	i = 0;
	while ( i++ < nbytes )			//	not yet reach to the end of first field
	{
		c = *p++;					//	get current byte
		if ( c == '\0' )			//	reach the end of string 'p'
		{
			*pfield = '\0';
			return 0;				//	no next field followed
		}
		else if ( c == ',' )		//	reach the end of first field
		{
			*pfield = '\0';
			return p;				//	return pointer of the next byte of ','
		}
		else
		{
			*pfield++ = c;			//	store data into buffer 'pfield'
		}
	}
	*pfield = '\0';					//	buffer size less than the first field's one

	while ( (c = *p++) )			//	to reach the end of first field
	{
		if ( c == ',' ) return p;	//	reach the end of first field
									//	and return pointer of the next byte of ','
	}
	return 0;						//	no next field followed
}