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Diffstat (limited to 'source/blender/blenlib/BLI_simple_expr.h')
| -rw-r--r-- | source/blender/blenlib/BLI_simple_expr.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_simple_expr.h b/source/blender/blenlib/BLI_simple_expr.h new file mode 100644 index 00000000000..8498f1a02e7 --- /dev/null +++ b/source/blender/blenlib/BLI_simple_expr.h @@ -0,0 +1,96 @@ +/* + * ***** 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__*/ |