7d32190a4c
If you give it a value x, the macro lets you pull a value out of each object that you want to compare to x.
70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/* -*- indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*-
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obt/bsearch.h for the Openbox window manager
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Copyright (c) 2010 Dana Jansens
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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See the COPYING file for a copy of the GNU General Public License.
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*/
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#ifndef __obt_bsearch_h
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#define __obt_bsearch_h
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#include <glib.h>
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G_BEGIN_DECLS
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/*! Setup to do a binary search on an array. */
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#define BSEARCH_SETUP() \
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register guint l_BSEARCH, r_BSEARCH, out_BSEARCH;
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/*! Helper macro that just returns the input */
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#define BSEARCH_IS_T(t) (t)
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/*! Search an array @ar holding elements of type @t, starting at index @start,
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with @size elements, looking for value @val. */
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#define BSEARCH(t, ar, start, size, val) \
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BSEARCH_CMP(t, ar, start, size, val, BSEARCH_IS_T)
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/*! Search an array @ar, starting at index @start,
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with @size elements, looking for value @val of type @t,
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using the macro @to_t to convert values in the arrau @ar to type @t.*/
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#define BSEARCH_CMP(t, ar, start, size, val, to_t) \
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{ \
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l_BSEARCH = (start); \
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r_BSEARCH = (start)+(size)-1; \
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while (l_BSEARCH <= r_BSEARCH) { \
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/* m is in the middle, but to the left if there's an even number \
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of elements */ \
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out_BSEARCH = l_BSEARCH + (r_BSEARCH - l_BSEARCH)/2; \
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if ((val) == to_t((ar)[out_BSEARCH])) { \
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break; \
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} \
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else if ((val) < to_t((ar)[out_BSEARCH]) && out_BSEARCH > 0) { \
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r_BSEARCH = out_BSEARCH-1; /* search to the left side */ \
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} \
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else \
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l_BSEARCH = out_BSEARCH+1; /* search to the left side */ \
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} \
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}
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/*! Returns true if the element last searched for was found in the array */
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#define BSEARCH_FOUND() (l_BSEARCH <= r_BSEARCH)
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/*! Returns the position in the array at which the element last searched for
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was found. */
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#define BSEARCH_AT() (out_BSEARCH)
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G_END_DECLS
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#endif
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