string.c

ADS环境下的类似linux内核的操作系统

/* MShowTec - www.mshowtec.com
** msLinux string.c ver1.0
** 20051221 lmjx create [e-mail]
**
*/

#define MSLINUX_STRING_C

__inline char *strcpy (char *dest, const char *src)
{
	char *p = dest;
	while(*src){
		*dest++ = *src++;
	}
	*dest = 0;	
	return p;
}

__inline char *strncpy (char *dest, const char *src, int count)
{
	char *p = dest;
	while((*src)&&(count>0)){
		*dest++ = *src++;
		count--;
	}
	while(count>0){
		*dest++ = 0;
		count--;
	}
	*dest = 0;
	return p;
}

__inline char *strcat (char *dest, const char *src)
{
	char *tmp = dest;

	while (*dest)
		dest++;
	while ((*dest++ = *src++) != '\0')
		;

	return tmp;
}

__inline char *strncat (char *dest, const char *src, int count)
{
	char *tmp = dest;

	if (count) {
		while (*dest)
			dest++;
		while ((*dest++ = *src++)) {
			if (--count == 0) {
				*dest = '\0';
				break;
			}
		}
	}

	return tmp;
}

__inline int strcmp (const char *csrc, const char *ct)
{
	while( 1 )
	{
		unsigned char s1 = *csrc++;
		unsigned char s2 = *ct++;

		if(  s1 > s2 )
			return 1;
		else if( s1 < s2 )
			return -1;
		else if( s1 == 0 && s2 == 0 )
			break;
	}
	return 0;
}

__inline int strncmp(const char * cs,const char * ct,int count)
{

	while( count-- )
	{
		unsigned char s1 = *cs++;
		unsigned char s2 = *ct++;

		if(  s1 > s2 )
			return 1;
		else if( s1 < s2 )
			return -1;
		else if( s1 == 0 && s2 == 0 )
			break;
	}
	return 0;

}

/**
 * strchr - Find the first occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
__inline char * strchr(const char * s, int c)
{
	for(; *s != (char) c; ++s)
		if (*s == '\0')
			return 0;
	return (char *) s;
}

/**
 * strrchr - Find the last occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
__inline char * strrchr(const char * s, int c)
{
       const char *p = s + strlen(s);
       do {
           if (*p == (char)c)
               return (char *)p;
       } while (--p >= s);
       return 0;
}


__inline int strlen (const char *s)
{
	int ret = 0;
	
	while(*s++){
		ret++;
	}
	return ret;
}

/**
 * strspn - Calculate the length of the initial substring of @s which only
 * 	contain letters in @accept
 * @s: The string to be searched
 * @accept: The string to search for
 */
__inline unsigned int strspn(const char *s, const char *accept)
{
	const char *p;
	const char *a;
	unsigned int count = 0;

	for (p = s; *p != '\0'; ++p) {
		for (a = accept; *a != '\0'; ++a) {
			if (*p == *a)
				break;
		}
		if (*a == '\0')
			return count;
		++count;
	}

	return count;
}


__inline void *memcpy (void *dest, const void *src, int n)
{
	void *p = dest;
	
	while(n>0){
		*((unsigned char*)dest)++ = *((unsigned char*)src)++;
		n--;
	}
	
	return p;
}

/**
 * memmove - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * Unlike memcpy(), memmove() copes with overlapping areas.
 */
__inline void * memmove(void * dest,const void *src,int count)
{
	char *tmp, *s;

	if (dest <= src) {
		tmp = (char *) dest;
		s = (char *) src;
		while (count--)
			*tmp++ = *s++;
		}
	else {
		tmp = (char *) dest + count;
		s = (char *) src + count;
		while (count--)
			*--tmp = *--s;
		}

	return dest;
}

/**
 * memcmp - Compare two areas of memory
 * @cs: One area of memory
 * @ct: Another area of memory
 * @count: The size of the area.
 */
__inline int memcmp(const void * cs,const void * ct,int count)
{
	const unsigned char *su1, *su2;
	int res = 0;

	for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
		if ((res = *su1 - *su2) != 0)
			break;
	return res;
}

/**
 * memscan - Find a character in an area of memory.
 * @addr: The memory area
 * @c: The byte to search for
 * @size: The size of the area.
 *
 * returns the address of the first occurrence of @c, or 1 byte past
 * the area if @c is not found
 */
__inline void * memscan(void * addr, int c, int size)
{
	unsigned char * p = (unsigned char *) addr;

	while (size) {
		if (*p == c)
			return (void *) p;
		p++;
		size--;
	}
  	return (void *) p;
}

/**
 * strstr - Find the first substring in a %NUL terminated string
 * @s1: The string to be searched
 * @s2: The string to search for
 */
__inline char * strstr(const char * s1,const char * s2)
{
	int l1, l2;

	l2 = strlen(s2);
	if (!l2)
		return (char *) s1;
	l1 = strlen(s1);
	while (l1 >= l2) {
		l1--;
		if (!memcmp(s1,s2,l2))
			return (char *) s1;
		s1++;
	}
	return 0;
}

/**
 * memchr - Find a character in an area of memory.
 * @s: The memory area
 * @c: The byte to search for
 * @n: The size of the area.
 *
 * returns the address of the first occurrence of @c, or %NULL
 * if @c is not found
 */
void *memchr(const void *s, int c, int n)
{
	const unsigned char *p = s;
	while (n-- != 0) {
        	if ((unsigned char)c == *p++) {
			return (void *)(p-1);
		}
	}
	return 0;
}


__inline void *memset (void *s, char c, int count)
{
	void *p = s;
	
	while(count>0){
		*((unsigned char*)s)++ = c;
	}
	return p;
}

__inline void itoa(int value, char *string, int radix)
{
	int i;
	int count = 0;
	unsigned long temp;
	unsigned long res;
	char ch[20];
	if(radix==10 && value<0){ch[0] = '-';count++;temp = 0-value;}
	else{temp = value;}
	while(1)
	{
		res = temp%radix;
		temp=temp/radix;
		if(res<10) ch[count++]=res+'0';
		else ch[count++]=res-10+'a';
		if(temp==0)
			break;
	}
	ch[count]='\0';
	string[0]='\0';
	for(i=0;i<count;i++)
		string[count-i-1]=ch[i];

	string[count]='\0';
}