map_noswiss.go

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package abi
     6  
     7  import (
     8  	"unsafe"
     9  )
    10  
    11  // Map constants common to several packages
    12  // runtime/runtime-gdb.py:MapTypePrinter contains its own copy
    13  const (
    14  	// Maximum number of key/elem pairs a bucket can hold.
    15  	OldMapBucketCountBits = 3 // log2 of number of elements in a bucket.
    16  	OldMapBucketCount     = 1 << OldMapBucketCountBits
    17  
    18  	// Maximum key or elem size to keep inline (instead of mallocing per element).
    19  	// Must fit in a uint8.
    20  	// Note: fast map functions cannot handle big elems (bigger than MapMaxElemBytes).
    21  	OldMapMaxKeyBytes  = 128
    22  	OldMapMaxElemBytes = 128 // Must fit in a uint8.
    23  )
    24  
    25  type OldMapType struct {
    26  	Type
    27  	Key    *Type
    28  	Elem   *Type
    29  	Bucket *Type // internal type representing a hash bucket
    30  	// function for hashing keys (ptr to key, seed) -> hash
    31  	Hasher     func(unsafe.Pointer, uintptr) uintptr
    32  	KeySize    uint8  // size of key slot
    33  	ValueSize  uint8  // size of elem slot
    34  	BucketSize uint16 // size of bucket
    35  	Flags      uint32
    36  }
    37  
    38  // Note: flag values must match those used in the TMAP case
    39  // in ../cmd/compile/internal/reflectdata/reflect.go:writeType.
    40  func (mt *OldMapType) IndirectKey() bool { // store ptr to key instead of key itself
    41  	return mt.Flags&1 != 0
    42  }
    43  func (mt *OldMapType) IndirectElem() bool { // store ptr to elem instead of elem itself
    44  	return mt.Flags&2 != 0
    45  }
    46  func (mt *OldMapType) ReflexiveKey() bool { // true if k==k for all keys
    47  	return mt.Flags&4 != 0
    48  }
    49  func (mt *OldMapType) NeedKeyUpdate() bool { // true if we need to update key on an overwrite
    50  	return mt.Flags&8 != 0
    51  }
    52  func (mt *OldMapType) HashMightPanic() bool { // true if hash function might panic
    53  	return mt.Flags&16 != 0
    54  }
    55
View as plain text