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comparison lib/libavutil/eval.h @ 2134:992d2e6f907d

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preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
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2133:e378232bfd36 2134:992d2e6f907d
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 for
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 */