windows-nt/Source/XPSP1/NT/base/crts/crtw32/misc/lsearch.c
2020-09-26 16:20:57 +08:00

89 lines
2.6 KiB
C

/***
*lsearch.c - linear search of an array
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* contains the _lsearch() function - linear search of an array
*
*Revision History:
* 06-19-85 TC initial version
* 05-14-87 JMB added function pragma for memcpy in compact/large mode
* for huge pointer support
* include sizeptr.h for SIZED definition
* 08-01-87 SKS Add include file for prototype of memcpy()
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 01-21-88 JCR Backed out _LOAD_DS...
* 10-30-89 JCR Added _cdecl to prototypes
* 03-14-90 GJF Replaced _cdecl with _CALLTYPE1, added #include
* <cruntime.h>, removed #include <register.h> and
* fixed the copyright. Also, cleaned up the formatting
* a bit.
* 04-05-90 GJF Added #include <search.h> and fixed the resulting
* compiler errors and warnings. Removed unreferenced
* local variable. Also, removed #include <sizeptr.h>.
* 07-25-90 SBM Replaced <stdio.h> by <stddef.h>
* 10-04-90 GJF New-style function declarator.
* 01-17-91 GJF ANSI naming.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
*
*******************************************************************************/
#include <cruntime.h>
#include <stddef.h>
#include <search.h>
#include <memory.h>
/***
*char *_lsearch(key, base, num, width, compare) - do a linear search
*
*Purpose:
* Performs a linear search on the array, looking for the value key
* in an array of num elements of width bytes in size. Returns
* a pointer to the array value if found; otherwise adds the
* key to the end of the list.
*
*Entry:
* char *key - key to search for
* char *base - base of array to search
* unsigned *num - number of elements in array
* int width - number of bytes in each array element
* int (*compare)() - pointer to function that compares two
* array values, returning 0 if they are equal and non-0
* if they are different. Two pointers to array elements
* are passed to this function.
*
*Exit:
* if key found:
* returns pointer to array element
* if key not found:
* adds the key to the end of the list, and increments
* *num.
* returns pointer to new element.
*
*Exceptions:
*
*******************************************************************************/
void * __cdecl _lsearch (
REG2 const void *key,
REG1 void *base,
REG3 unsigned int *num,
unsigned int width,
int (__cdecl *compare)(const void *, const void *)
)
{
unsigned int place = 0;
while (place < *num )
if (!(*compare)(key,base))
return(base);
else
{
base = (char *)base + width;
place++;
}
(void) memcpy( base, key, width );
(*num)++;
return( base );
}