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diff --git a/lib/elstring.c b/lib/elstring.c
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+++ b/lib/elstring.c
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+/* Length/String string handling
+ * Copyright (C) 2009 Chris Hall (GMCH), Highwayman
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2, or (at your
+ * option) any later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING. If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <ctype.h>
+
+#include "elstring.h"
+#include "memory.h"
+
+/*==============================================================================
+ * Create and free
+ */
+
+/*------------------------------------------------------------------------------
+ * Create a new elstring
+ */
+extern elstring
+els_new(void)
+{
+ return XCALLOC(MTYPE_TMP, sizeof(elstring_t)) ;
+
+ confirm(ELSTRING_INIT_ALL_ZEROS) ;
+} ;
+
+/*------------------------------------------------------------------------------
+ * Initialise or create a new elstring
+ */
+extern elstring
+els_init_new(elstring els)
+{
+ if (els == NULL)
+ els = els_new() ;
+ else
+ memset(els, 0, sizeof(elstring_t)) ;
+
+ confirm(ELSTRING_INIT_ALL_ZEROS) ;
+
+ return els ;
+} ;
+
+/*------------------------------------------------------------------------------
+ * Release dynamically allocated elstring.
+ *
+ * Returns NULL.
+ *
+ * NB: it is the callers responsibility to free the contents of the elstring.
+ * if that is required, before freeing the elstring itself.
+ */
+extern elstring
+els_free(elstring els)
+{
+ if (els != NULL)
+ XFREE(MTYPE_TMP, els) ;
+
+ return NULL ;
+} ;
+
+/*==============================================================================
+ * Various comparisons
+ */
+
+/*------------------------------------------------------------------------------
+ * Compare two elstrings -- returns the usual -ve, 0, +ve cmp result.
+ *
+ * NULL elstring is treated as empty.
+ */
+extern int
+els_cmp(elstring a, elstring b)
+{
+ const uchar* ap ;
+ const uchar* bp ;
+ ulen al, bl ;
+ ulen n ;
+
+ ap = els_body(a) ; /* NULL if a is NULL */
+ bp = els_body(b) ;
+ al = els_len(a) ; /* zero if a is NULL */
+ bl = els_len(b) ;
+
+ n = (al <= bl) ? al : bl ; /* min(al, bl) */
+
+ while (n)
+ {
+ int d = *ap++ - *bp++ ;
+ if (d != 0)
+ return d ;
+ --n ;
+ } ;
+
+ return al < bl ? -1 : (al == bl) ? 0 : +1 ;
+} ;
+
+/*------------------------------------------------------------------------------
+ * Compare elstring against word.
+ *
+ * Returns: -1 => elstring and word match to end of elstring
+ * 0 => elstring and word match completely
+ * +1 => elstring and word do not match
+ *
+ * NULLs are treated as empty strings.
+ *
+ * An empty elstring will completely match an empty word.
+ * An empty elstring will partly match any non-empty word.
+ */
+extern int
+els_cmp_word(elstring a, const char* w)
+{
+ const uchar* ap, * ep ;
+ ulen al, wl ;
+
+ al = els_len(a) ; /* zero if a is NULL */
+ wl = (w != NULL) ? strlen(w) : 0 ; /* zero if w is NULL */
+
+ if (al > wl)
+ return +1 ; /* no match if longer */
+
+ if (al == 0)
+ return (wl == 0) ? 0 : -1 ; /* exact or partial if empty */
+
+ ap = els_body_nn(a) ;
+
+ /* Neither string is empty */
+
+ if (*ap != *w)
+ return +1 ; /* quick out if no match for 1st char */
+
+ ep = ap + al - 1 ;
+ while (ap < ep)
+ {
+ if (*++ap != *++w)
+ return 1 ;
+ } ;
+
+ return al == wl ? 0 : -1 ; /* full or partial match */
+} ;
+
+/*------------------------------------------------------------------------------
+ * Compare significant parts of two qstrings -- returns the usual -ve, 0, +ve
+ * cmp result.
+ *
+ * By significant, mean excluding leading/trailing isspace() and treating
+ * multiple isspace() as single isspace().
+ *
+ * Compares the 'len' portions of the strings.
+ *
+ * NULL elstring is treated as empty.
+ */
+extern int
+els_cmp_sig(elstring a, elstring b)
+{
+ cpp_t ap ;
+ cpp_t bp ;
+
+ /* Set up pointers and dispense with leading and trailing isspace()
+ *
+ * Dummy up if NULL
+ */
+ els_cpp(ap, a) ; /* NULL if a is NULL */
+
+ while ((ap->p < ap->e) && isspace(*ap->p))
+ ++ap->p ;
+ while ((ap->p < ap->e) && isspace(*(ap->e - 1)))
+ --ap->e ;
+
+ els_cpp(bp, b) ;
+
+ while ((bp->p < bp->e) && isspace(*bp->p))
+ ++bp->p ;
+ while ((bp->p < bp->e) && isspace(*(bp->e - 1)))
+ --bp->e ;
+
+ /* Now set about finding the first difference */
+ while ((ap->p != ap->e) && (bp->p != bp->e))
+ {
+ if (isspace(*ap->p) && isspace(*bp->p))
+ {
+ do { ++ap->p ; } while (isspace(*ap->p)) ;
+ do { ++bp->p ; } while (isspace(*bp->p)) ;
+ } ;
+
+ if (*ap->p != *bp->p)
+ return (*ap->p < *bp->p) ? -1 : +1 ;
+
+ ++ap->p ;
+ ++bp->p ;
+ } ;
+
+ /* No difference before ran out of one or both */
+ if (ap->p != ap->e)
+ return +1 ;
+ else if (bp->p != bp->e)
+ return -1 ;
+ else
+ return 0 ;
+} ;
+
+/*------------------------------------------------------------------------------
+ * Are two elstrings equal ? -- returns true if strings equal.
+ */
+extern bool
+els_equal(elstring a, elstring b)
+{
+ const uchar* ap ;
+ const uchar* bp ;
+ ulen n ;
+
+ n = els_len(b) ; /* zero if b is NULL */
+ if (n != els_len(a))
+ return false ;
+
+ ap = els_body(a) ; /* NULL if a is NULL */
+ bp = els_body(b) ;
+
+ while (n)
+ {
+ if (*ap++ != *bp++)
+ return false ;
+ --n ;
+ } ;
+
+ return true ;
+} ;
+
+/*------------------------------------------------------------------------------
+ * Is 'b' a leading substring of 'a' ? -- returns true if it is.
+ *
+ * If 'b' is empty it is always a leading substring.
+ */
+extern bool
+els_substring(elstring a, elstring b)
+{
+ const uchar* ap ;
+ const uchar* bp ;
+ ulen n ;
+
+ n = els_len(b) ; /* zero if b is NULL */
+ if (n > els_len(a))
+ return false ;
+
+ ap = els_body(a) ;
+ bp = els_body(b) ;
+
+ while (n)
+ {
+ if (*ap++ != *bp++)
+ return false ;
+ --n ;
+ } ;
+
+ return true ;
+} ;
+
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