Initial release: Go Jdenticon library v0.1.0

- Core library with SVG and PNG generation
- CLI tool with generate and batch commands
- Cross-platform path handling for Windows compatibility
- Comprehensive test suite with integration tests

jdenticon/validation.go

@@ -0,0 +1,85 @@
+package jdenticon
+
+import (
+	"github.com/ungluedlabs/go-jdenticon/internal/engine"
+)
+
+// validation.go contains helper functions for input validation and DoS protection.
+
+// validateInputs performs common validation for input string and size parameters.
+// This provides centralized validation logic used across all public API functions.
+func validateInputs(input string, size int, config Config) error {
+	// Validate input string length
+	if maxLen := config.effectiveMaxInputLength(); maxLen != -1 && len(input) > maxLen {
+		return NewErrValueTooLarge("InputLength", maxLen, len(input))
+	}
+
+	// Validate that input is not empty
+	if input == "" {
+		return NewErrInvalidInput("input", input, "cannot be empty")
+	}
+
+	// Validate base icon size (must be positive)
+	if size <= 0 {
+		return ErrInvalidSize(size)
+	}
+
+	// Validate icon size against configured limit
+	if maxSize := config.effectiveMaxIconSize(); maxSize != -1 && size > maxSize {
+		return NewErrValueTooLarge("IconSize", maxSize, size)
+	}
+
+	return nil
+}
+
+// validateComplexity performs complexity validation for an input string.
+// This should be called after basic input validation and hash computation.
+func validateComplexity(hash string, config Config) error {
+	if maxComplexity := config.effectiveMaxComplexity(); maxComplexity != -1 {
+		// Create a temporary engine generator to calculate complexity
+		// This is needed to access the CalculateComplexity method
+		engineConfig := engine.DefaultGeneratorConfig()
+		engineConfig.ColorConfig = engine.ColorConfig{
+			IconPadding:         config.Padding,
+			ColorSaturation:     config.ColorSaturation,
+			GrayscaleSaturation: config.GrayscaleSaturation,
+			ColorLightness: engine.LightnessRange{
+				Min: config.ColorLightnessRange[0],
+				Max: config.ColorLightnessRange[1],
+			},
+			GrayscaleLightness: engine.LightnessRange{
+				Min: config.GrayscaleLightnessRange[0],
+				Max: config.GrayscaleLightnessRange[1],
+			},
+			Hues:      config.HueRestrictions,
+			BackColor: nil, // Not needed for complexity calculation
+		}
+
+		tempGenerator, err := engine.NewGeneratorWithConfig(engineConfig)
+		if err != nil {
+			return err
+		}
+
+		complexity, err := tempGenerator.CalculateComplexity(hash)
+		if err != nil {
+			return err
+		}
+
+		if complexity > maxComplexity {
+			return NewErrComplexityLimitExceeded(maxComplexity, complexity, hash)
+		}
+	}
+	return nil
+}
+
+// validatePNGSize performs additional validation for PNG functions that use supersampling.
+// This checks the effective size (size * supersampling) against configured limits.
+func validatePNGSize(size int, config Config) error {
+	// Check effective size for PNG with supersampling
+	effectiveSize := size * config.PNGSupersampling
+	if maxSize := config.effectiveMaxIconSize(); maxSize != -1 && effectiveSize > maxSize {
+		return NewErrEffectiveSizeTooLarge(maxSize, effectiveSize, size, config.PNGSupersampling)
+	}
+
+	return nil
+}