e385b1074b
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2362 42af7a65-404d-4744-a932-0658087f49c3
128 lines
4.7 KiB
C
128 lines
4.7 KiB
C
/****************************************************************************
|
|
* binfmt/symtab_findorderedbyvalue.c
|
|
*
|
|
* Copyright (C) 2009 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <stddef.h>
|
|
#include <debug.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
#include <nuttx/symtab.h>
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Function Prototypes
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Data
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/***********************************************************************
|
|
* Public Functions
|
|
***********************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: symtab_findorderedbyvalue
|
|
*
|
|
* Description:
|
|
* Find the symbol in the symbol table whose value closest (but not greater
|
|
* than), the provided value. This version assumes that table is ordered
|
|
* with respect to symbol name.
|
|
*
|
|
* Returned Value:
|
|
* A reference to the symbol table entry if an entry with the matching
|
|
* name is found; NULL is returned if the entry is not found.
|
|
*
|
|
****************************************************************************/
|
|
|
|
FAR const struct symtab_s *
|
|
symtab_findorderedbyvalue(FAR const struct symtab_s *symtab,
|
|
FAR void *value, int nsyms)
|
|
{
|
|
int low = 0;
|
|
int high = nsyms -1;
|
|
int mid;
|
|
|
|
/* Loop until the range has been isolated to a single symbol table
|
|
* entry that may or may not match the search name.
|
|
*/
|
|
|
|
DEBUGASSERT(symtab != NULL);
|
|
while (low < high)
|
|
{
|
|
/* Compare the name to the one in the middle. (or just below
|
|
* the middle in the case where one is even and one is odd).
|
|
*/
|
|
|
|
mid = (low + high) >> 1;
|
|
if ( value < symtab[mid].sym_value)
|
|
{
|
|
high = mid - 1;
|
|
}
|
|
else if (value > symtab[mid].sym_value)
|
|
{
|
|
low = mid + 1;
|
|
}
|
|
else /* if (value == symtab[mid].sym_value) */
|
|
{
|
|
return &symtab[mid];
|
|
}
|
|
}
|
|
|
|
/* low == high... One final check. We might not have actually tested
|
|
* the final symtab[] name.
|
|
*
|
|
* Example: Only the last pass through loop, suppose low = 1, high = 2,
|
|
* mid = 1, and symtab[high].sym_name == name. Then we would get here with
|
|
* low = 2, high = 2, but symtab[2].sym_name was never tested.
|
|
*/
|
|
|
|
return value == symtab[low].sym_value ? &symtab[low] : NULL;
|
|
}
|
|
|