Rename AVEvalExpr to AVExpr, as suggested by Michael.
[libav.git] / libavcodec / eval.h
1 /*
2 * simple arithmetic expression evaluator
3 *
4 * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file libavcodec/eval.h
25 * eval header.
26 */
27
28 #ifndef AVCODEC_EVAL_H
29 #define AVCODEC_EVAL_H
30
31 typedef struct ff_expr_s AVExpr;
32
33 /**
34 * Parses and evaluates an expression.
35 * Note, this is significantly slower than ff_parse_eval()
36 * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)"
37 * @param func1 NULL terminated array of function pointers for functions which take 1 argument
38 * @param func2 NULL terminated array of function pointers for functions which take 2 arguments
39 * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0}
40 * @param func1_name NULL terminated array of zero terminated strings of func1 identifers
41 * @param func2_name NULL terminated array of zero terminated strings of func2 identifers
42 * @param error pointer to a char* which is set to an error message if something goes wrong
43 * @param const_value a zero terminated array of values for the identifers from const_name
44 * @param opaque a pointer which will be passed to all functions from func1 and func2
45 * @return the value of the expression
46 */
47 double ff_eval2(const char *s, const double *const_value, const char * const *const_name,
48 double (**func1)(void *, double), const char **func1_name,
49 double (**func2)(void *, double, double), const char **func2_name,
50 void *opaque, const char **error);
51
52 /**
53 * Parses a expression.
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
61 * @return AVExpr which must be freed with ff_eval_free by the user when it is not needed anymore
62 * NULL if anything went wrong
63 */
64 AVExpr * ff_parse(const char *s, const char * const *const_name,
65 double (**func1)(void *, double), const char **func1_name,
66 double (**func2)(void *, double, double), const char **func2_name,
67 const char **error);
68 /**
69 * Evaluates a previously parsed expression.
70 * @param const_value a zero terminated array of values for the identifers from ff_parse const_name
71 * @param opaque a pointer which will be passed to all functions from func1 and func2
72 * @return the value of the expression
73 */
74 double ff_parse_eval(AVExpr * e, const double *const_value, void *opaque);
75 void ff_eval_free(AVExpr * e);
76
77 /**
78 * Parses the string in numstr and returns its value as a double. If
79 * the string is empty, contains only whitespaces, or does not contain
80 * an initial substring that has the expected syntax for a
81 * floating-point number, no conversion is performed. In this case,
82 * returns a value of zero and the value returned in tail is the value
83 * of numstr.
84 *
85 * @param numstr a string representing a number, may contain one of
86 * the International System number postfixes, for example 'K', 'M',
87 * 'G'. If 'i' is appended after the postfix, powers of 2 are used
88 * instead of powers of 10. The 'B' postfix multiplies the value for
89 * 8, and can be appended after another postfix or used alone. This
90 * allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.
91 * @param tail if non-NULL puts here the pointer to the char next
92 * after the last parsed character
93 */
94 double av_strtod(const char *numstr, char **tail);
95
96 #endif /* AVCODEC_EVAL_H */