eval.h 5.17 KB
Newer Older
1 2 3
/*
 * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
 *
4
 * This file is part of Libav.
5
 *
6
 * Libav is free software; you can redistribute it and/or
7 8
 * modify it under the terms of the GNU Lesser General Public
 * 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
 * Libav is distributed in the hope that it will be useful,
12 13 14 15 16
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
17
 * License along with Libav; if not, write to the Free Software
18 19 20 21
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
22
 * @file
23
 * simple arithmetic expression evaluator
24 25
 */

26 27
#ifndef AVUTIL_EVAL_H
#define AVUTIL_EVAL_H
28

29 30
#include "avutil.h"

31
typedef struct AVExpr AVExpr;
32

Michael Niedermayer's avatar
Michael Niedermayer committed
33
/**
34
 * Parse and evaluate an expression.
35
 * Note, this is significantly slower than av_expr_eval().
36
 *
37 38
 * @param res a pointer to a double where is put the result value of
 * the expression, or NAN in case of error
Stefano Sabatini's avatar
Stefano Sabatini committed
39 40 41 42
 * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
 * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
 * @param const_values a zero terminated array of values for the identifiers from const_names
 * @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
Stefano Sabatini's avatar
Stefano Sabatini committed
44
 * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers
45 46
 * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments
 * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2
47
 * @param log_ctx parent logging context
48 49
 * @return 0 in case of success, a negative value corresponding to an
 * AVERROR code otherwise
Michael Niedermayer's avatar
Michael Niedermayer committed
50
 */
51
int av_expr_parse_and_eval(double *res, const char *s,
52 53 54
                           const char * const *const_names, const double *const_values,
                           const char * const *func1_names, double (* const *funcs1)(void *, double),
                           const char * const *func2_names, double (* const *funcs2)(void *, double, double),
55
                           void *opaque, int log_offset, void *log_ctx);
56

Michael Niedermayer's avatar
Michael Niedermayer committed
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.
Stefano Sabatini's avatar
Stefano Sabatini committed
64 65 66
 * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
 * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
 * @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
Stefano Sabatini's avatar
Stefano Sabatini committed
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 72
 * @return 0 in case of success, a negative value corresponding to an
 * AVERROR code otherwise
Michael Niedermayer's avatar
Michael Niedermayer committed
73
 */
74
int av_expr_parse(AVExpr **expr, const char *s,
75 76 77
                  const char * const *const_names,
                  const char * const *func1_names, double (* const *funcs1)(void *, double),
                  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
78
                  int log_offset, void *log_ctx);
79

Michael Niedermayer's avatar
Michael Niedermayer committed
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
Michael Niedermayer's avatar
Michael Niedermayer committed
85 86
 * @return the value of the expression
 */
87 88 89 90 91 92 93
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque);

/**
 * Free a parsed expression previously created with av_expr_parse().
 */
void av_expr_free(AVExpr *e);

94
/**
95
 * Parse the string in numstr and return its value as a double. If
96 97 98 99 100 101 102 103 104 105 106 107 108 109
 * the string is empty, contains only whitespaces, or does not contain
 * an initial substring that has the expected syntax for a
 * floating-point number, no conversion is performed. In this case,
 * returns a value of zero and the value returned in tail is the value
 * of numstr.
 *
 * @param numstr a string representing a number, may contain one of
 * the International System number postfixes, for example 'K', 'M',
 * 'G'. If 'i' is appended after the postfix, powers of 2 are used
 * instead of powers of 10. The 'B' postfix multiplies the value for
 * 8, and can be appended after another postfix or used alone. This
 * allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.
 * @param tail if non-NULL puts here the pointer to the char next
 * after the last parsed character
110 111 112
 */
double av_strtod(const char *numstr, char **tail);

113
#endif /* AVUTIL_EVAL_H */