File UIImage+Extensions.swift has 560 lines of code (exceeds 250 allowed). Consider refactoring. Open
import CoreGraphics
import Foundation
import UIKit
#if canImport(CoreImage)
import AccelerateFunction blur has a Cognitive Complexity of 28 (exceeds 5 allowed). Consider refactoring. Open
func blur(radius blurRadius: CGFloat, saturation: CGFloat = 1.8, tintColor: UIColor? = nil, maskImage: UIImage? = nil) -> UIImage {
guard size.width > 1 && size.height > 1, let selfCGImage = cgImage else {
return self
}
- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Function blur has 90 lines of code (exceeds 25 allowed). Consider refactoring. Open
func blur(radius blurRadius: CGFloat, saturation: CGFloat = 1.8, tintColor: UIColor? = nil, maskImage: UIImage? = nil) -> UIImage {
guard size.width > 1 && size.height > 1, let selfCGImage = cgImage else {
return self
}
Function scaleProportionally has 39 lines of code (exceeds 25 allowed). Consider refactoring. Open
func scaleProportionally(toSize targetSize: CGSize) -> UIImage {
let sourceImage: UIImage = self
let newTargetSize: CGSize = targetSize
let imageSize: CGSize = sourceImage.sizeFunction scaleProportionally has 35 lines of code (exceeds 25 allowed). Consider refactoring. Open
func scaleProportionally(toMinimumSize targetSize: CGSize) -> UIImage {
let sourceImage: UIImage = self
let newTargetSize: CGSize = targetSize
let imageSize: CGSize = sourceImage.sizeFunction scaleProportionally has 32 lines of code (exceeds 25 allowed). Consider refactoring. Open
func scaleProportionally(toMaximumSize targetSize: CGSize) -> UIImage {
let newTargetSize: CGSize = targetSize
if size.width > newTargetSize.width || newTargetSize.width == newTargetSize.height, size.width > size.height {
let factor: CGFloat = (newTargetSize.width * 100) / size.widthFunction scaleProportionally has a Cognitive Complexity of 8 (exceeds 5 allowed). Consider refactoring. Open
func scaleProportionally(toSize targetSize: CGSize) -> UIImage {
let sourceImage: UIImage = self
let newTargetSize: CGSize = targetSize
let imageSize: CGSize = sourceImage.size- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Function cmykHalftone has 6 arguments (exceeds 4 allowed). Consider refactoring. Open
func cmykHalftone(center: CIVector, width: Float, angle: Float, sharpness: Float, gcr: Float, ucr: Float) -> UIImage { // swiftlint:disable:this function_parameter_countFunction scaleProportionally has a Cognitive Complexity of 7 (exceeds 5 allowed). Consider refactoring. Open
func scaleProportionally(toMinimumSize targetSize: CGSize) -> UIImage {
let sourceImage: UIImage = self
let newTargetSize: CGSize = targetSize
let imageSize: CGSize = sourceImage.size- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Avoid too many return statements within this function. Open
return selfAvoid too many return statements within this function. Open
return selfAvoid too many return statements within this function. Open
return outputImageAvoid too many return statements within this function. Open
return selfFunction scaleProportionally has a Cognitive Complexity of 6 (exceeds 5 allowed). Consider refactoring. Open
func scaleProportionally(toMaximumSize targetSize: CGSize) -> UIImage {
let newTargetSize: CGSize = targetSize
if size.width > newTargetSize.width || newTargetSize.width == newTargetSize.height, size.width > size.height {
let factor: CGFloat = (newTargetSize.width * 100) / size.width- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Function should have complexity 10 or less: currently complexity equals 15 Open
func blur(radius blurRadius: CGFloat, saturation: CGFloat = 1.8, tintColor: UIColor? = nil, maskImage: UIImage? = nil) -> UIImage {- Exclude checks
Function body should span 40 lines or less excluding comments and whitespace: currently spans 74 lines Open
func blur(radius blurRadius: CGFloat, saturation: CGFloat = 1.8, tintColor: UIColor? = nil, maskImage: UIImage? = nil) -> UIImage {- Exclude checks
Similar blocks of code found in 2 locations. Consider refactoring. Open
if size.width > newTargetSize.width || newTargetSize.width == newTargetSize.height, size.width > size.height {
let factor: CGFloat = (newTargetSize.width * 100) / size.width
let newWidth: CGFloat = (size.width * factor) / 100
let newHeight: CGFloat = (size.height * factor) / 100
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 139.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
} else if size.height > newTargetSize.height || newTargetSize.width == newTargetSize.height, size.width < size.height {
let factor: CGFloat = (newTargetSize.width * 100) / size.height
let newWidth: CGFloat = (size.width * factor) / 100
let newHeight: CGFloat = (size.height * factor) / 100
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 139.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if widthFactor > heightFactor {
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5
} else if widthFactor < heightFactor {
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 67.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
if widthFactor < heightFactor {
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5
} else if widthFactor > heightFactor {
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 67.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
func bumpDistortion(center: CIVector, radius: Float, scale: Float) -> UIImage {
return filter(name: "CIBumpDistortion", parameters: [kCIInputCenterKey: center, kCIInputRadiusKey: radius, kCIInputScaleKey: scale])
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 62.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
func circularWrap(center: CIVector, radius: Float, angle: Float) -> UIImage {
return filter(name: "CICircularWrap", parameters: [kCIInputCenterKey: center, kCIInputRadiusKey: radius, kCIInputAngleKey: angle])
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 62.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Identical blocks of code found in 2 locations. Consider refactoring. Open
guard let cgImage = cgImage, let context = CGContext(data: nil, width: Int(rect.width), height: Int(rect.height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: 0) else {
return self
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Identical blocks of code found in 2 locations. Consider refactoring. Open
guard let cgImage = cgImage, let context = CGContext(data: nil, width: Int(rect.width), height: Int(rect.height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: 0) else {
return self
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
func circleSplashDistortion(center: CIVector, radius: Float) -> UIImage {
return filter(name: "CICircleSplashDistortion", parameters: [kCIInputCenterKey: center, kCIInputRadiusKey: radius])
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 50.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
func bloom(radius: Float, intensity: Float) -> UIImage {
return filter(name: "CIBloom", parameters: [kCIInputRadiusKey: radius, kCIInputIntensityKey: intensity])
}- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 50.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
var effectInBuffer = vImage_Buffer(data: effectInContext.data, height: UInt(effectInContext.height), width: UInt(effectInContext.width), rowBytes: effectInContext.bytesPerRow)- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 42.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 2 locations. Consider refactoring. Open
var effectOutBuffer = vImage_Buffer(data: effectOutContext.data, height: UInt(effectOutContext.height), width: UInt(effectOutContext.width), rowBytes: effectOutContext.bytesPerRow)- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 42.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76