blob: dacd22b96e66cec8818f1b2f5c806df166eb9d86
1 | /* |
2 | * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at> |
3 | * |
4 | * This file is part of FFmpeg. |
5 | * |
6 | * FFmpeg is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public |
8 | * License as published by the Free Software Foundation; either |
9 | * version 2.1 of the License, or (at your option) any later version. |
10 | * |
11 | * FFmpeg is distributed in the hope that it will be useful, |
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 |
17 | * License along with FFmpeg; if not, write to the Free Software |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
19 | */ |
20 | |
21 | /** |
22 | * @file |
23 | * simple arithmetic expression evaluator |
24 | */ |
25 | |
26 | #ifndef AVUTIL_EVAL_H |
27 | #define AVUTIL_EVAL_H |
28 | |
29 | #include "avutil.h" |
30 | |
31 | typedef struct AVExpr AVExpr; |
32 | |
33 | /** |
34 | * Parse and evaluate an expression. |
35 | * Note, this is significantly slower than av_expr_eval(). |
36 | * |
37 | * @param res a pointer to a double where is put the result value of |
38 | * the expression, or NAN in case of error |
39 | * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" |
40 | * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} |
41 | * @param const_values a zero terminated array of values for the identifiers from const_names |
42 | * @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers |
43 | * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument |
44 | * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers |
45 | * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments |
46 | * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 |
47 | * @param log_ctx parent logging context |
48 | * @return >= 0 in case of success, a negative value corresponding to an |
49 | * AVERROR code otherwise |
50 | */ |
51 | int av_expr_parse_and_eval(double *res, const char *s, |
52 | const char * const *const_names, const double *const_values, |
53 | const char * const *func1_names, double (* const *funcs1)(void *, double), |
54 | const char * const *func2_names, double (* const *funcs2)(void *, double, double), |
55 | void *opaque, int log_offset, void *log_ctx); |
56 | |
57 | /** |
58 | * Parse an expression. |
59 | * |
60 | * @param expr a pointer where is put an AVExpr containing the parsed |
61 | * value in case of successful parsing, or NULL otherwise. |
62 | * The pointed to AVExpr must be freed with av_expr_free() by the user |
63 | * when it is not needed anymore. |
64 | * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" |
65 | * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} |
66 | * @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers |
67 | * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument |
68 | * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers |
69 | * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments |
70 | * @param log_ctx parent logging context |
71 | * @return >= 0 in case of success, a negative value corresponding to an |
72 | * AVERROR code otherwise |
73 | */ |
74 | int av_expr_parse(AVExpr **expr, const char *s, |
75 | const char * const *const_names, |
76 | const char * const *func1_names, double (* const *funcs1)(void *, double), |
77 | const char * const *func2_names, double (* const *funcs2)(void *, double, double), |
78 | int log_offset, void *log_ctx); |
79 | |
80 | /** |
81 | * Evaluate a previously parsed expression. |
82 | * |
83 | * @param const_values a zero terminated array of values for the identifiers from av_expr_parse() const_names |
84 | * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 |
85 | * @return the value of the expression |
86 | */ |
87 | double av_expr_eval(AVExpr *e, const double *const_values, void *opaque); |
88 | |
89 | /** |
90 | * Free a parsed expression previously created with av_expr_parse(). |
91 | */ |
92 | void av_expr_free(AVExpr *e); |
93 | |
94 | /** |
95 | * Parse the string in numstr and return its value as a double. If |
96 | * the string is empty, contains only whitespaces, or does not contain |
97 | * an initial substring that has the expected syntax for a |
98 | * floating-point number, no conversion is performed. In this case, |
99 | * returns a value of zero and the value returned in tail is the value |
100 | * of numstr. |
101 | * |
102 | * @param numstr a string representing a number, may contain one of |
103 | * the International System number postfixes, for example 'K', 'M', |
104 | * 'G'. If 'i' is appended after the postfix, powers of 2 are used |
105 | * instead of powers of 10. The 'B' postfix multiplies the value by |
106 | * 8, and can be appended after another postfix or used alone. This |
107 | * allows using for example 'KB', 'MiB', 'G' and 'B' as postfix. |
108 | * @param tail if non-NULL puts here the pointer to the char next |
109 | * after the last parsed character |
110 | */ |
111 | double av_strtod(const char *numstr, char **tail); |
112 | |
113 | #endif /* AVUTIL_EVAL_H */ |
114 |