strlib.c

internich公司实现的一个非常非常小的OS

/*
 * FILENAME: strlib.c
 *
 * Copyright 1998- 2004 By InterNiche Technologies Inc. All rights reserved
 * Portions Copyright 1993 by NetPort software.
 *
 * Universal string  functions, provided for systems with no C library. 
 * Created for minimal C lib support. Portions of this may only have been  
 * lightly tested.
 *
 * MODULE: NTF
 *
 * ROUTINES: strcat(), strchr(), strcmp(), strcpy(), 
 * ROUTINES: strlen(), strncmp(), strncpy(), strstr(), 
 *
 * PORTABLE: yes
 */

#include "license.h"
#include "ipport.h"
#include "in_utils.h"

#ifdef INICHE_LIBS


/* FUNCTION: strlen()
 * 
 * PARAM1: char * str
 *
 * RETURNS: 
 */

int
strlen(char * str)
{
   int   len   =  0;

   while (*str++) len++;
      return(len);
}


/* FUNCTION: strcpy()
 * 
 * PARAM1: char * dest
 * PARAM2: char * src
 *
 * RETURNS: 
 */

char *   
strcpy(char * dest, char * src)
{
   char *   ret   =  dest;

   while (*src)
      *dest++ = *src++;
   *dest = 0;
   return ret;
}


/* FUNCTION: strncpy()
 * 
 * PARAM1: char * dest
 * PARAM2: char * src
 * PARAM3: int maxcopy
 *
 * RETURNS: 
 */

char *   
strncpy(char * dest, char * src, int maxcopy)
{
   char *   ret   =  dest;

   while (*src && maxcopy)
   {   
      *dest++ = *src++;
      maxcopy--;
   }
   *dest = 0;  /* null terminate string */
   return ret;
}



/* FUNCTION: strcmp()
 * 
 * PARAM1: char * str1
 * PARAM2: char * str2
 *
 * RETURNS: 
 */

int
strcmp(char * str1, char * str2)
{
   while (*str1)
   {
      if (*str1 > *str2) return 1;
         if (*str1++ < *str2++) return -1;
         }
   /* added by jharan, 4-26-99 */
   /* if we have not gotten to the end of str2 by the time we have
      gotten to the end of the str1, then str1 is less than str2 */
   if (*str2)
      return -1;
   return 0;
}



/* FUNCTION: strncmp()
 * 
 * PARAM1: char * str1
 * PARAM2: char * str2
 * PARAM3: int length
 *
 * RETURNS: 
 */

int 
strncmp(char * str1, char * str2, int length)
{
   while (length--)
   {
      if (*str1 > *str2)
         return 1;
      if (*str1++ < *str2++)
         return -1;
   }
   return 0;
}


/* FUNCTION: strcat()
 * 
 * PARAM1: char * str1
 * PARAM2: char * str2
 *
 * RETURNS: 
 */

char *   
strcat(char * str1, char * str2)
{
   char *   cp;

   cp = str1;
   while (*cp)    /* find null at the end of str1 */
      cp++;
   while (*str2)  /* copy str2 onto end */
      *cp++ = *str2++;
   *cp = 0;       /* null terminate */
   return str1;
}



/* FUNCTION: strchr()
 * 
 * PARAM1: char * str
 * PARAM2: char chr
 *
 * RETURNS: 
 */

char * 
strchr(char * str, char chr)
{
   while (*str)
   {
      if (*str == chr)
         return str;
      else
         str++;
   }
   if (chr == 0)  /* caller was looking for null */
      return str; /* return pointer to null */
   return (char*)0;
}

/* FUNCTION: strstr()
 *
 * strstr(str1, str2) - look for str2 inside str1
 *
 * 
 * PARAM1: char * str1
 * PARAM2: char * str2
 *
 * RETURNS: 
 */

char * 
strstr(char * str1, char * str2)
{
   while (*str1)
   {
      if (*str1 == *str2)  /* found first char of str2 in str1 */
      {
         if (strncmp(str1, str2, strlen(str2)) == 0)
         {
            return str1;   /* found str2 at str1 */
         }
      }
      str1++;
   }
   return (char*)0;
}

#endif   /* INICHE_LIBS */