1 | /* |
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2 | * libcaca ASCII-Art library |
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3 | * Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org> |
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4 | * All Rights Reserved |
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5 | * |
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6 | * $Id: math.c 192 2003-11-16 12:28:29Z sam $ |
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7 | * |
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8 | * This library is free software; you can redistribute it and/or |
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9 | * modify it under the terms of the GNU Lesser General Public |
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10 | * License as published by the Free Software Foundation; either |
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11 | * version 2 of the License, or (at your option) any later version. |
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12 | * |
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13 | * This library is distributed in the hope that it will be useful, |
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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16 | * Lesser General Public License for more details. |
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17 | * |
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18 | * You should have received a copy of the GNU Lesser General Public |
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19 | * License along with this library; if not, write to the Free Software |
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20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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21 | * 02111-1307 USA |
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22 | */ |
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23 | |
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24 | #include "config.h" |
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25 | |
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26 | #include <stdlib.h> |
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27 | |
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28 | #include "caca.h" |
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29 | #include "caca_internals.h" |
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30 | |
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31 | int caca_rand(int min, int max) |
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32 | { |
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33 | return min + (int)((1.0*(max-min+1)) * rand() / (RAND_MAX+1.0)); |
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34 | } |
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35 | |
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36 | unsigned int caca_sqrt(unsigned int a) |
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37 | { |
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38 | if(a == 0) |
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39 | return 0; |
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40 | |
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41 | if(a < 1000000000) |
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42 | { |
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43 | unsigned int x = a < 10 ? 1 |
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44 | : a < 1000 ? 10 |
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45 | : a < 100000 ? 100 |
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46 | : a < 10000000 ? 1000 |
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47 | : 10000; |
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48 | |
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49 | /* Newton's method. Three iterations would be more than enough. */ |
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50 | x = (x * x + a) / x / 2; |
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51 | x = (x * x + a) / x / 2; |
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52 | x = (x * x + a) / x / 2; |
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53 | x = (x * x + a) / x / 2; |
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54 | |
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55 | return x; |
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56 | } |
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57 | |
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58 | return 2 * caca_sqrt(a / 4); |
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59 | } |
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60 | |
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