| 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 */ |