cmptype.h

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/*-------------------------------------------------------------------------
 *
 * cmptype.h
 *    POSTGRES compare type definitions.
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/access/cmptype.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef CMPTYPE_H
#define CMPTYPE_H
 
/*
 * CompareType - fundamental semantics of certain operators
 *
 * These enum symbols represent the fundamental semantics of certain operators
 * that the system needs to have some hardcoded knowledge about.  (For
 * example, RowCompareExpr needs to know which operators can be determined to
 * act like =, <>, <, etc.)  Index access methods map (some of) strategy
 * numbers to these values so that the system can know about the meaning of
 * (some of) the operators without needing hardcoded knowledge of index AM's
 * strategy numbering.
 *
 * XXX Currently, this mapping is not fully developed and most values are
 * chosen to match btree strategy numbers, which is not going to work very
 * well for other access methods.
 */
typedef enum CompareType
{
    COMPARE_INVALID = 0,
    COMPARE_LT = 1,             /* BTLessStrategyNumber */
    COMPARE_LE = 2,             /* BTLessEqualStrategyNumber */
    COMPARE_EQ = 3,             /* BTEqualStrategyNumber */
    COMPARE_GE = 4,             /* BTGreaterEqualStrategyNumber */
    COMPARE_GT = 5,             /* BTGreaterStrategyNumber */
    COMPARE_NE = 6,             /* no such btree strategy */
    COMPARE_OVERLAP,
    COMPARE_CONTAINED_BY,
} CompareType;
 
#endif                          /* CMPTYPE_H */