README
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mask
The mask package provides utilities for managing bitmasks in Go, including functionality to mark bits, check if bits are set, and compare bitmasks for various conditions. The package supports multiple build configurations (e.g., 64-bit, 256-bit, 512-bit) to accommodate different mask sizes.
Features
Mark: Set specific bits in the mask.Contains: Check if a specific bit is set.ContainsAll: Check if all bits in one mask are contained in another.ContainsAny: Check if any bits in one mask are contained in another.ContainsNone: Check if none of the bits in one mask are set in another.
Build Configurations
The package supports different configurations using Go build tags:
- Default (64-bits)
- m256 (256-bits)
- m512 (512 bits)
- m1024 (1024 bits)
Mask 256
The package contains a fixed Mask256{} type, regardless of build tags.
go test -tags m256
Installation
import "github.com/TheBitDrifter/mask"
Usage
Mark a Bit
To set a specific bit in the mask:
var m mask.Mask
m.Mark(3) // Sets the 3rd bit
To check if a specific bit is set:
if m.Contains(3) {
fmt.Println("Bit 3 is set!")
}
Compare Bitmasks
You can compare two Mask instances to see if they share certain bits.
Check if all bits in one mask are contained in another:
var other mask.Mask
other.Mark(5)
if m.ContainsAll(other) {
fmt.Println("All bits in `other` are set in `m`.")
}
Check if any bits in one mask are contained in another:
if m.ContainsAny(other) {
fmt.Println("At least one bit in `other` is set in `m`.")
}
Check if no bits in one mask are set in another:
if m.ContainsNone(other) {
fmt.Println("No bits in `other` are set in `m`.")
}
Check for an Empty Mask To check if a mask is empty (i.e., no bits are set):
if mask.isEmpty(m) {
fmt.Println("Mask is empty.")
}
Documentation
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Overview ¶
Package mask provides utilities for managing bitmasks in Go, supporting various mask sizes through build configurations.
The mask package implements functionality to manipulate and compare bitmasks, with support for configurable sizes (64, 256, 512, or 1024 bits) based on build tags. A fixed-size Mask256 is also available regardless of build configuration.
Mask Types ¶
The package defines two primary types:
- Mask: A variable-sized bitmask whose size depends on build tags
- Mask256: A fixed 256-bit bitmask available in all configurations
Basic Usage ¶
Creating and manipulating masks:
// Create a new mask
var m mask.Mask
// Set bits in the mask
m.Mark(3) // Set bit 3
m.Mark(42) // Set bit 42
// Check if a bit is set
if m.Contains(3) {
// Bit 3 is set
}
// Clear a bit
m.Unmark(3)
Comparing Masks ¶
Masks can be compared for various conditions:
var m1, m2 mask.Mask
m1.Mark(1)
m1.Mark(2)
m2.Mark(2)
m2.Mark(3)
// Check if m1 contains all bits in m2
if m1.ContainsAll(m2) {
// m1 has all bits set that are set in m2
}
// Check if m1 contains any bits in m2
if m1.ContainsAny(m2) {
// m1 and m2 share at least one bit
}
// Check if m1 contains none of the bits in m2
if m1.ContainsNone(m2) {
// m1 and m2 have no bits in common
}
// Check if a mask is empty (no bits set)
if m1.IsEmpty() {
// No bits are set in m1
}
Build Configurations ¶
The package supports different bit sizes through build tags:
- Default: 64-bit mask (no build tag required)
- m256: 256-bit mask
- m512: 512-bit mask
- m1024: 1024-bit mask
Example of building with a specific configuration:
go build -tags m256
The Mask256 type is always available with a fixed 256-bit size, regardless of which build configuration is used.
Index ¶
Constants ¶
const (
MaxBits = 64
)
MaxBits defines the maximum number of bits supported by this mask implementation
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Mask ¶
type Mask [maskSize]uint64
func (Mask) ContainsAll ¶
ContainsAll checks if all bits set in the other mask are also set in this mask
func (Mask) ContainsAny ¶
ContainsAny checks if any bit set in the other mask is also set in this mask
func (Mask) ContainsNone ¶
ContainsNone checks if none of the bits set in the other mask are set in this mask Returns false if the other mask is empty
type Mask256 ¶
type Mask256 [256]uint64
Mask256 represents a 256-element bit mask using an array of uint64
func (Mask256) ContainsAll ¶
ContainsAll returns true if this mask contains all bits set in the other mask
func (Mask256) ContainsAny ¶
ContainsAny returns true if this mask contains any bits set in the other mask
func (Mask256) ContainsNone ¶
ContainsNone returns true if this mask contains none of the bits set in the other mask
Source Files