| 1 | /* useful.h |
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| 2 | * Lots of oddments that come in handy generally |
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| 3 | * Copyright (C) 1993-2003,2004,2010,2011,2014,2025 Olly Betts |
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| 4 | * |
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| 5 | * This program is free software; you can redistribute it and/or modify |
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| 6 | * it under the terms of the GNU General Public License as published by |
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| 7 | * the Free Software Foundation; either version 2 of the License, or |
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| 8 | * (at your option) any later version. |
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| 9 | * |
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| 10 | * This program is distributed in the hope that it will be useful, |
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 13 | * GNU General Public License for more details. |
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| 14 | * |
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| 15 | * You should have received a copy of the GNU General Public License |
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| 16 | * along with this program; if not, see |
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| 17 | * <https://www.gnu.org/licenses/>. |
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| 18 | */ |
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| 19 | |
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| 20 | /* only include once */ |
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| 21 | #ifndef USEFUL_H |
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| 22 | #define USEFUL_H |
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| 23 | |
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| 24 | #ifndef PACKAGE |
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| 25 | # error config.h must be included first in each C/C++ source file |
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| 26 | #endif |
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| 27 | |
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| 28 | #include <stdio.h> |
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| 29 | #include <math.h> |
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| 30 | |
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| 31 | /* M_PI, etc may be defined in math.h */ |
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| 32 | #ifndef M_PI |
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| 33 | # define M_PI 3.14159265358979323846264338327950288419716939937510582097494459 |
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| 34 | #endif |
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| 35 | #ifndef M_PI_2 |
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| 36 | # define M_PI_2 (M_PI / 2.0) |
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| 37 | #endif |
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| 38 | #ifndef M_PI_4 |
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| 39 | # define M_PI_4 (M_PI / 4.0) |
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| 40 | #endif |
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| 41 | |
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| 42 | #define MM_PER_INCH 25.4 /* exact value */ |
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| 43 | #define METRES_PER_FOOT 0.3048 /* exact value */ |
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| 44 | #define POINTS_PER_INCH 72.0 |
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| 45 | #define POINTS_PER_MM (POINTS_PER_INCH / MM_PER_INCH) |
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| 46 | |
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| 47 | // Write a newline char. |
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| 48 | #define putnl() PUTCHAR('\n') |
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| 49 | |
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| 50 | // Write a newline char to a file. |
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| 51 | #define fputnl(FH) PUTC('\n', (FH)) |
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| 52 | |
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| 53 | // Square X. |
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| 54 | #define sqrd(X) ((X) * (X)) |
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| 55 | |
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| 56 | /* 2D Euclidean distance */ |
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| 57 | #ifndef HAVE_HYPOT |
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| 58 | # define hypot(X, Y) sqrt(sqrd((double)(X)) + sqrd((double)(Y))) |
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| 59 | #endif |
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| 60 | #define rad(X) ((M_PI / 180.0) * (X)) /* convert from degrees to radians */ |
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| 61 | #define deg(X) ((180.0 / M_PI) * (X)) /* convert from radians to degrees */ |
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| 62 | |
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| 63 | /* macro to convert argument to a string literal */ |
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| 64 | #define STRING(X) STRING_(X) |
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| 65 | #define STRING_(X) #X |
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| 66 | |
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| 67 | #endif /* !USEFUL_H */ |
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