strncpy.c

来自「test file nucleus source」· C语言 代码 · 共 85 行

/*************************************************************************
*
*               Copyright Mentor Graphics Corporation 2002
*                         All Rights Reserved.
*
* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS
* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS
* SUBJECT TO LICENSE TERMS.
*
*************************************************************************/

/*************************************************************************
* FILE NAME                                     VERSION
*
*       strncpy.c                               Nucleus Common Library 1.1
*
* DESCRIPTION
*
*       This file contains the implementation of NCL_strncpy.
*
* DATA STRUCTURES
*
*       None.
*
* FUNCTIONS
*
*       NCL_strncpy
*
* DEPENDENCIES
*
*       ncl.h
*       string.h
*       nucleus.h
*
************************************************************************/

#define NU_NCL_SOURCE_FILE

#include "ncl\inc\ncl.h"
#include "ncl\inc\string.h"
#include "plus\nucleus.h"                                /* MMU Support */

/*************************************************************************
*
*   FUNCTION
*
*       NCL_strncpy
*
*   DESCRIPTION
*
*       Copy s2 to s1, and make sure that at EXACTLY n characters are
*       copied (padded with 0 if necessary).  Does not always append a
*       null.
*
*   INPUTS
*
*       s1                  Destination
*       s2                  Source
*       n                   Number of bytes to copy
*
*   OUTPUTS
*
*       char*               Pointer to result.
*
*************************************************************************/

char *NCL_strncpy(register char *s1, register const char *s2,
                   register size_t n)
{
    register char *p = s1;

    while (n > 0)
    {
        --n;
        if (!(*s1++ = *s2++))
            break;
    }

    while (n-- > 0)
        *s1++ = 0;

    return p;
}