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 module ffmpeg.libavutil.eval; 27 28 extern (C): 29 import ffmpeg; @nogc nothrow: 30 31 struct 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 ( 52 double* res, 53 const(char)* s, 54 const(char*)* const_names, 55 const(double)* const_values, 56 const(char*)* func1_names, 57 double function (void*, double)* funcs1, 58 const(char*)* func2_names, 59 double function (void*, double, double)* funcs2, 60 void* opaque, 61 int log_offset, 62 void* log_ctx); 63 64 /** 65 * Parse an expression. 66 * 67 * @param expr a pointer where is put an AVExpr containing the parsed 68 * value in case of successful parsing, or NULL otherwise. 69 * The pointed to AVExpr must be freed with av_expr_free() by the user 70 * when it is not needed anymore. 71 * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" 72 * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} 73 * @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers 74 * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument 75 * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers 76 * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments 77 * @param log_ctx parent logging context 78 * @return >= 0 in case of success, a negative value corresponding to an 79 * AVERROR code otherwise 80 */ 81 int av_expr_parse ( 82 AVExpr** expr, 83 const(char)* s, 84 const(char*)* const_names, 85 const(char*)* func1_names, 86 double function (void*, double)* funcs1, 87 const(char*)* func2_names, 88 double function (void*, double, double)* funcs2, 89 int log_offset, 90 void* log_ctx); 91 92 /** 93 * Evaluate a previously parsed expression. 94 * 95 * @param const_values a zero terminated array of values for the identifiers from av_expr_parse() const_names 96 * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 97 * @return the value of the expression 98 */ 99 double av_expr_eval (AVExpr* e, const(double)* const_values, void* opaque); 100 101 /** 102 * Free a parsed expression previously created with av_expr_parse(). 103 */ 104 void av_expr_free (AVExpr* e); 105 106 /** 107 * Parse the string in numstr and return its value as a double. If 108 * the string is empty, contains only whitespaces, or does not contain 109 * an initial substring that has the expected syntax for a 110 * floating-point number, no conversion is performed. In this case, 111 * returns a value of zero and the value returned in tail is the value 112 * of numstr. 113 * 114 * @param numstr a string representing a number, may contain one of 115 * the International System number postfixes, for example 'K', 'M', 116 * 'G'. If 'i' is appended after the postfix, powers of 2 are used 117 * instead of powers of 10. The 'B' postfix multiplies the value by 118 * 8, and can be appended after another postfix or used alone. This 119 * allows using for example 'KB', 'MiB', 'G' and 'B' as postfix. 120 * @param tail if non-NULL puts here the pointer to the char next 121 * after the last parsed character 122 */ 123 double av_strtod (const(char)* numstr, char** tail); 124 125 /* AVUTIL_EVAL_H */