From 0b99215c0e6a3e24dfdd99f83395e1231a015601 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Sat, 5 Jun 2010 12:01:28 +0000 Subject: Move eval.c and eval.h from libavcodec to libavutil, and make the eval API public. Originally committed as revision 23485 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavutil/eval.h | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 libavutil/eval.h (limited to 'libavutil/eval.h') diff --git a/libavutil/eval.h b/libavutil/eval.h new file mode 100644 index 0000000000..38b4c25ce5 --- /dev/null +++ b/libavutil/eval.h @@ -0,0 +1,111 @@ +/* + * Copyright (c) 2002 Michael Niedermayer + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * 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 + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * simple arithmetic expression evaluator + */ + +#ifndef AVUTIL_EVAL_H +#define AVUTIL_EVAL_H + +typedef struct AVExpr AVExpr; + +/** + * Parses and evaluates an expression. + * Note, this is significantly slower than av_eval_expr(). + * + * @param res a pointer to a double where is put the result value of + * the expression, or NAN in case of error + * @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 + * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument + * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers + * @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 + * @param log_ctx parent logging context + * @return 0 in case of success, a negative value corresponding to an + * AVERROR code otherwise + */ +int av_parse_and_eval_expr(double *res, const char *s, + 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), + void *opaque, int log_offset, void *log_ctx); + +/** + * Parses an expression. + * + * @param expr a pointer where is put an AVExpr containing the parsed + * value in case of successfull parsing, or NULL otherwise. + * The pointed to AVExpr must be freed with av_free_expr() by the user + * when it is not needed anymore. + * @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 + * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument + * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers + * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments + * @param log_ctx parent logging context + * @return 0 in case of success, a negative value corresponding to an + * AVERROR code otherwise + */ +int av_parse_expr(AVExpr **expr, const char *s, + 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), + int log_offset, void *log_ctx); + +/** + * Evaluates a previously parsed expression. + * + * @param const_values a zero terminated array of values for the identifiers from av_parse_expr() const_names + * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 + * @return the value of the expression + */ +double av_eval_expr(AVExpr *e, const double *const_values, void *opaque); + +/** + * Frees a parsed expression previously created with av_parse_expr(). + */ +void av_free_expr(AVExpr *e); + +/** + * Parses the string in numstr and returns its value as a double. If + * 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 + */ +double av_strtod(const char *numstr, char **tail); + +#endif /* AVUTIL_EVAL_H */ -- cgit v1.2.3