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+/****************************************************************************
+ * binfmt/symtab_findorderedbyname.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 <sys/types.h>
+
+#include <string.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_findorderedbyname
+ *
+ * Description:
+ * Find the symbol in the symbol table with the matching name.
+ * This version assumes that table ordered with respect to symbol name.
+ *
+ * This function uses qsort() to implement the search and, hence, is a lot
+ * larger than symbtab_findbyname(). This function not be used, unless
+ * the symbol table is large and the performance benefit is worth the
+ * increased size.
+ *
+ * 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_findorderedbyname(FAR const struct symtab_s *symtab,
+ FAR const char *name, int nsyms)
+{
+ int low = 0;
+ int high = nsyms -1;
+ int mid;
+ int cmp;
+
+ /* 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 && name != 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;
+ cmp = strcmp(name, symtab[mid].sym_name);
+ if (cmp < 0)
+ {
+ /* name < symtab[mid].sym_name */
+
+ high = mid - 1;
+ }
+ else if (cmp > 0)
+ {
+ /* name > symtab[mid].sym_name */
+
+ low = mid + 1;
+ }
+ else
+ {
+ /* symtab[mid].sym_name == name */
+
+ 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 strcmp(name, symtab[low].sym_name) == 0 ? &symtab[low] : NULL;
+}
+