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// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package abi
import (
"unsafe"
)
// Map constants common to several packages
// runtime/runtime-gdb.py:MapTypePrinter contains its own copy
const (
// Maximum number of key/elem pairs a bucket can hold.
OldMapBucketCountBits = 3 // log2 of number of elements in a bucket.
OldMapBucketCount = 1 << OldMapBucketCountBits
// Maximum key or elem size to keep inline (instead of mallocing per element).
// Must fit in a uint8.
// Note: fast map functions cannot handle big elems (bigger than MapMaxElemBytes).
OldMapMaxKeyBytes = 128
OldMapMaxElemBytes = 128 // Must fit in a uint8.
)
type OldMapType struct {
Type
Key *Type
Elem *Type
Bucket *Type // internal type representing a hash bucket
// function for hashing keys (ptr to key, seed) -> hash
Hasher func(unsafe.Pointer, uintptr) uintptr
KeySize uint8 // size of key slot
ValueSize uint8 // size of elem slot
BucketSize uint16 // size of bucket
Flags uint32
}
// Note: flag values must match those used in the TMAP case
// in ../cmd/compile/internal/reflectdata/reflect.go:writeType.
func (mt *OldMapType) IndirectKey() bool { // store ptr to key instead of key itself
return mt.Flags&1 != 0
}
func (mt *OldMapType) IndirectElem() bool { // store ptr to elem instead of elem itself
return mt.Flags&2 != 0
}
func (mt *OldMapType) ReflexiveKey() bool { // true if k==k for all keys
return mt.Flags&4 != 0
}
func (mt *OldMapType) NeedKeyUpdate() bool { // true if we need to update key on an overwrite
return mt.Flags&8 != 0
}
func (mt *OldMapType) HashMightPanic() bool { // true if hash function might panic
return mt.Flags&16 != 0
}
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