Mercurial > hg > octave-nkf > gnulib-hg

annotate lib/i-ring.c @ 9659:5680cf5b5595

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md2: clarify comments to say that alignment is not required. * lib/md2.h: Remove warning about alignment in comment. * lib/md2.c (md2_read_ctx, md2_finish_ctx): Doc fix, alignment has never been required.
author Simon Josefsson <simon@josefsson.org>
date Thu, 31 Jan 2008 11:10:36 +0100
parents bbbbbf4cd1c5
children b5e42ef33b49
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1 /* a simple ring buffer
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2 Copyright (C) 2006 Free Software Foundation, Inc.
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3
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4 This program is free software: you can redistribute it and/or modify
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5 it under the terms of the GNU General Public License as published by
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6 the Free Software Foundation; either version 3 of the License, or
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7 (at your option) any later version.
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8
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9 This program is distributed in the hope that it will be useful,
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10 but WITHOUT ANY WARRANTY; without even the implied warranty of
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11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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12 GNU General Public License for more details.
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13
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14 You should have received a copy of the GNU General Public License
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15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
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16
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17 /* written by Jim Meyering */
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18
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19 #include <config.h>
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20 #include "i-ring.h"
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21
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22 #include <stdlib.h>
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23
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24 void
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25 i_ring_init (I_ring *ir, int default_val)
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26 {
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27 int i;
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28 ir->ir_empty = true;
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29 ir->ir_front = 0;
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30 ir->ir_back = 0;
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31 for (i = 0; i < I_RING_SIZE; i++)
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32 ir->ir_data[i] = default_val;
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33 ir->ir_default_val = default_val;
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34 }
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35
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36 bool
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37 i_ring_empty (I_ring const *ir)
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38 {
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39 return ir->ir_empty;
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40 }
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41
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42 int
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43 i_ring_push (I_ring *ir, int val)
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44 {
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45 unsigned int dest_idx = (ir->ir_front + !ir->ir_empty) % I_RING_SIZE;
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46 int old_val = ir->ir_data[dest_idx];
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47 ir->ir_data[dest_idx] = val;
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48 ir->ir_front = dest_idx;
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49 if (dest_idx == ir->ir_back)
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50 ir->ir_back = (ir->ir_back + !ir->ir_empty) % I_RING_SIZE;
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51 ir->ir_empty = false;
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52 return old_val;
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53 }
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54
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55 int
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56 i_ring_pop (I_ring *ir)
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57 {
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58 int top_val;
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59 if (i_ring_empty (ir))
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60 abort ();
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61 top_val = ir->ir_data[ir->ir_front];
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62 ir->ir_data[ir->ir_front] = ir->ir_default_val;
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63 if (ir->ir_front == ir->ir_back)
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64 ir->ir_empty = true;
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65 else
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66 ir->ir_front = ((ir->ir_front + I_RING_SIZE - 1) % I_RING_SIZE);
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67 return top_val;
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68 }