Factorize code into a single function.
[libav.git] / libavcodec / eval.h
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b2f86c17 1/*
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2 * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
3 *
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4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
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7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
b78e7197 9 * version 2.1 of the License, or (at your option) any later version.
b2f86c17 10 *
b78e7197 11 * FFmpeg is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
b78e7197 17 * License along with FFmpeg; if not, write to the Free Software
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
ba87f080 22 * @file
8c216473 23 * simple arithmetic expression evaluator
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24 */
25
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26#ifndef AVCODEC_EVAL_H
27#define AVCODEC_EVAL_H
b2f86c17 28
a3731cad 29typedef struct AVExpr AVExpr;
5fccafdb 30
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31/**
32 * Parses and evaluates an expression.
4565caf1 33 * Note, this is significantly slower than ff_eval_expr().
f54978f1 34 *
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35 * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)"
36 * @param func1 NULL terminated array of function pointers for functions which take 1 argument
37 * @param func2 NULL terminated array of function pointers for functions which take 2 arguments
38 * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0}
39 * @param func1_name NULL terminated array of zero terminated strings of func1 identifers
40 * @param func2_name NULL terminated array of zero terminated strings of func2 identifers
41 * @param error pointer to a char* which is set to an error message if something goes wrong
42 * @param const_value a zero terminated array of values for the identifers from const_name
43 * @param opaque a pointer which will be passed to all functions from func1 and func2
44 * @return the value of the expression
45 */
a367be1e 46double ff_parse_and_eval_expr(const char *s, const double *const_value, const char * const *const_name,
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47 double (* const *func1)(void *, double), const char * const *func1_name,
48 double (* const *func2)(void *, double, double), const char * const *func2_name,
20e4beae 49 void *opaque, const char **error);
b2f86c17 50
21d4d5da 51/**
94e57758 52 * Parses an expression.
f54978f1 53 *
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54 * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)"
55 * @param func1 NULL terminated array of function pointers for functions which take 1 argument
56 * @param func2 NULL terminated array of function pointers for functions which take 2 arguments
57 * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0}
58 * @param func1_name NULL terminated array of zero terminated strings of func1 identifers
59 * @param func2_name NULL terminated array of zero terminated strings of func2 identifers
60 * @param error pointer to a char* which is set to an error message if something goes wrong
f8fea468 61 * @return AVExpr which must be freed with ff_free_expr() by the user when it is not needed anymore
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62 * NULL if anything went wrong
63 */
1235429c 64AVExpr *ff_parse_expr(const char *s, const char * const *const_name,
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65 double (* const *func1)(void *, double), const char * const *func1_name,
66 double (* const *func2)(void *, double, double), const char * const *func2_name,
20e4beae 67 const char **error);
f54978f1 68
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69/**
70 * Evaluates a previously parsed expression.
f54978f1 71 *
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72 * @param const_value a zero terminated array of values for the identifers from ff_parse const_name
73 * @param opaque a pointer which will be passed to all functions from func1 and func2
74 * @return the value of the expression
75 */
4565caf1 76double ff_eval_expr(AVExpr * e, const double *const_value, void *opaque);
f8fea468 77
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78/**
79 * Frees a parsed expression previously created with ff_parse().
80 */
f8fea468 81void ff_free_expr(AVExpr *e);
85b4eb08 82
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83/**
84 * Parses the string in numstr and returns its value as a double. If
85 * the string is empty, contains only whitespaces, or does not contain
86 * an initial substring that has the expected syntax for a
87 * floating-point number, no conversion is performed. In this case,
88 * returns a value of zero and the value returned in tail is the value
89 * of numstr.
90 *
91 * @param numstr a string representing a number, may contain one of
92 * the International System number postfixes, for example 'K', 'M',
93 * 'G'. If 'i' is appended after the postfix, powers of 2 are used
94 * instead of powers of 10. The 'B' postfix multiplies the value for
95 * 8, and can be appended after another postfix or used alone. This
96 * allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.
97 * @param tail if non-NULL puts here the pointer to the char next
98 * after the last parsed character
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99 */
100double av_strtod(const char *numstr, char **tail);
101
98790382 102#endif /* AVCODEC_EVAL_H */