From 9871e574d52b16a68f31906d8b102362b0dd6ec7 Mon Sep 17 00:00:00 2001
From: Simon Kellet <sik00038@students.stir.ac.uk>
Date: Wed, 22 Jan 2025 19:18:49 +0000
Subject: [PATCH] better glitching algorithm

---
 glitch.go | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/glitch.go b/glitch.go
index 81b7f94..5d2f3c5 100644
--- a/glitch.go
+++ b/glitch.go
@@ -7,8 +7,16 @@ import (
 	"path/filepath"
 )
 
+func fillSliceWithASCII(slice []byte) {
+	const asciiMin = 16
+	const asciiMax = 150
+
+	for i := range slice {
+		slice[i] = byte(rand.Int32N(asciiMax-asciiMin+1) + asciiMin)
+	}
+}
+
 func glitchImage(inputFile string, outputFile string, shitSize int64, iterations int64) error {
-	// Prepend the "output" directory to the output file
 	outputFilePath := filepath.Join("output", outputFile)
 
 	// Open the source file for reading
@@ -31,6 +39,10 @@ func glitchImage(inputFile string, outputFile string, shitSize int64, iterations
 
 	// Get the size of the destination file
 	fileSize := fileInfo.Size()
+	if fileSize == 0 {
+		fmt.Println("Cannot glitch file with size of zero bytes!")
+		return fmt.Errorf("input file is zero bytes")
+	}
 
 	// Generate a random offset within the file
 	var i int64
@@ -43,6 +55,7 @@ func glitchImage(inputFile string, outputFile string, shitSize int64, iterations
 
 		// Generate random data and write it in
 		shit := make([]byte, shitSize)
+		fillSliceWithASCII(shit)
 		_, err = destination.Write(shit)
 		check(err, "failed to write shit data: %w")
 
@@ -68,21 +81,28 @@ func copyImage(inputFile string, outputFile string) error {
 	_, err = destination.ReadFrom(source)
 	check(err, "failed to copy file contents: %w")
 
+	// no errors
 	return nil
 }
 
-func generateGlitchedSequence(inputFile string, fileExt string, totalImages int, shitSize int64, iterations int64, chanceToRandom int32) {
+func generateGlitchedSequence(inputFile string, fileExt string, totalImages int, shitSize int64, iterations int64, chanceToRandom int32) error {
 	for i := 1; i <= totalImages; i++ {
 		outputFileName := fmt.Sprintf("img_glitched_%d.%s", i, fileExt)
 
 		if rand.Int32N(100) < chanceToRandom {
 			// Glitched image
 			err := glitchImage(inputFile, outputFileName, shitSize, iterations)
-			check(err, "failed to glitch image: %w")
+			if err != nil {
+				return fmt.Errorf("Cannot glitch image")
+			}
 		} else {
 			// Normal image
 			err := copyImage(inputFile, outputFileName)
-			check(err, "failed to copy normal image: %w")
+			if err != nil {
+				return fmt.Errorf("Cannot glitch image")
+			}
 		}
 	}
+	// no errors
+	return nil
 }