1 files changed, 107 insertions, 0 deletions
diff --git a/src/include/util_Expression.h b/src/include/util_Expression.h
new file mode 100644
index 00000000..85ead356
--- /dev/null
+++ b/src/include/util_Expression.h
@@ -0,0 +1,107 @@
+ /*@@
+   @header    util_Expression.h
+   @date      Tue Sep 19 22:02:45 2000
+   @author    Tom Goodale
+   @desc 
+   Header for expression stuff.
+   @enddesc
+   @version $Header$
+ @@*/
+
+#ifndef __UTIL_EXPRESSION_H__
+#define __UTIL_EXPRESSION_H__ 1
+
+#ifdef __cplusplus
+extern "C" 
+{
+#endif
+
+  /* These data types are for internal use only. */
+
+  /* Defined operators */
+typedef enum {OP_NONE,
+              OP_EQUALS,
+              OP_LESS_THAN,
+              OP_GREATER_THAN,
+              OP_LEQUALS,
+              OP_GEQUALS,
+              OP_AND,
+              OP_OR,
+              OP_PLUS,
+              OP_MINUS,
+              OP_DIV,
+              OP_TIMES,
+              OP_POWER,
+              OP_ACOS,
+              OP_ASIN,
+              OP_ATAN,
+              OP_CEIL,
+              OP_COS, 
+              OP_COSH,
+              OP_EXP,
+              OP_FABS,
+              OP_FLOOR,
+              OP_LOG,
+              OP_LOG10,
+              OP_SIN,
+              OP_SINH,
+              OP_SQRT,
+              OP_TAN,
+              OP_TANH}
+  uExpressionOpcode;
+
+  /* What sort of expression types we have. */
+typedef enum {val,unary,binary} uExpressionType;
+
+  /* RPN object. */
+typedef struct 
+{
+  uExpressionType type;
+
+  union
+  {
+    uExpressionOpcode opcode;
+    int varnum;
+  } token;
+} uExpressionToken;
+
+  /* Parsed expression object. */
+typedef struct
+{
+  int ntokens;
+  uExpressionToken *tokens;
+  int nvars;
+  const char **vars;
+} uExpressionInternals;
+
+/* Beginning of externally useable objects. */
+
+  /* Structure to hold values. */
+typedef struct 
+{
+  enum {rval,ival} type;
+  
+  union 
+  {
+    double rval;
+    int    ival;
+  } value;
+} uExpressionValue;
+
+  /* Externally visible representation of the expression. */
+typedef uExpressionInternals *uExpression;
+
+uExpression Util_ExpressionParse(const char *expression);
+
+int Util_ExpressionEvaluate(const uExpression buffer,
+                            uExpressionValue *retval,
+                            int (*eval)(int, const char * const *, uExpressionValue *, void *),
+                            void *data);
+
+void Util_ExpressionFree(uExpression buffer);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __UTIL_EXPRESSION_H__ */