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/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* The Original Code is Copyright (C) 2018 Blender Foundation, Alexander Gavrilov
* All rights reserved.
*
* Contributor(s): Alexander Gavrilov
*
* ***** END GPL LICENSE BLOCK *****
*/
#ifndef __BLI_SIMPLE_EXPR_H__
#define __BLI_SIMPLE_EXPR_H__
/** \file BLI_simple_expr.h
* \ingroup bli
* \author Alexander Gavrilov
* \since 2018
*
* Simple evaluator for a subset of Python expressions that can be
* computed using purely double precision floating point values.
*
* Supported subset:
*
* - Identifiers use only ASCII characters.
* - Literals:
* floating point and decimal integer.
* - Constants:
* pi, True, False
* - Operators:
* +, -, *, /, ==, !=, <, <=, >, >=, and, or, not, ternary if
* - Functions:
* radians, degrees,
* abs, fabs, floor, ceil, trunc, int,
* sin, cos, tan, asin, acos, atan, atan2,
* exp, log, sqrt, pow, fmod
*
* The implementation has no global state and can be used multithreaded.
*/
#ifdef __cplusplus
extern "C" {
#endif
/** Opaque structure containing pre-parsed data for evaluation. */
typedef struct ParsedSimpleExpr ParsedSimpleExpr;
/** Simple expression evaluation return code. */
typedef enum eSimpleExpr_EvalStatus {
SIMPLE_EXPR_SUCCESS = 0,
/* Computation errors; result is still set, but may be NaN */
SIMPLE_EXPR_DIV_BY_ZERO,
SIMPLE_EXPR_MATH_ERROR,
/* Expression dependent errors or bugs; result is 0 */
SIMPLE_EXPR_INVALID,
SIMPLE_EXPR_FATAL_ERROR,
} eSimpleExpr_EvalStatus;
/** Free the parsed data; NULL argument is ok. */
void BLI_simple_expr_free(struct ParsedSimpleExpr *expr);
/** Check if the parsing result is valid for evaluation. */
bool BLI_simple_expr_is_valid(struct ParsedSimpleExpr *expr);
/** Check if the parsed expression always evaluates to the same value. */
bool BLI_simple_expr_is_constant(struct ParsedSimpleExpr *expr);
/** Parse the expression for evaluation later.
* Returns non-NULL even on failure; use is_valid to check.
*/
ParsedSimpleExpr *BLI_simple_expr_parse(const char *expression, int num_params, const char **param_names);
/** Evaluate the expression with the given parameters.
* The order and number of parameters must match the names given to parse.
*/
eSimpleExpr_EvalStatus BLI_simple_expr_evaluate(struct ParsedSimpleExpr *expr, double *result, int num_params, const double *params);
#ifdef __cplusplus
}
#endif
#endif /* __BLI_SIMPLE_EXPR_H__*/
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