From de65f1fc823af65f759e669932be773a9f924ca4 Mon Sep 17 00:00:00 2001
From: "Grail Finder (aider)" <wohilas@gmail.com>
Date: Mon, 10 Mar 2025 20:25:21 +0300
Subject: fix: add error handling for binary.Write and remove unused variable

---
 pngmeta/altwriter.go  | 32 ++++++++++++++++++++++++--------
 pngmeta/metareader.go |  1 -
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/pngmeta/altwriter.go b/pngmeta/altwriter.go
index ebef172..aec972a 100644
--- a/pngmeta/altwriter.go
+++ b/pngmeta/altwriter.go
@@ -96,10 +96,18 @@ func processChunks(data []byte) ([][]byte, []byte, error) {
 		}
 
 		fullChunk := bytes.NewBuffer(nil)
-		binary.Write(fullChunk, binary.BigEndian, chunkLength)
-		fullChunk.Write(chunkType)
-		fullChunk.Write(chunkData)
-		fullChunk.Write(crc)
+		if err := binary.Write(fullChunk, binary.BigEndian, chunkLength); err != nil {
+			return nil, nil, fmt.Errorf("error writing chunk length: %w", err)
+		}
+		if _, err := fullChunk.Write(chunkType); err != nil {
+			return nil, nil, fmt.Errorf("error writing chunk type: %w", err)
+		}
+		if _, err := fullChunk.Write(chunkData); err != nil {
+			return nil, nil, fmt.Errorf("error writing chunk data: %w", err)
+		}
+		if _, err := fullChunk.Write(crc); err != nil {
+			return nil, nil, fmt.Errorf("error writing CRC: %w", err)
+		}
 
 		switch string(chunkType) {
 		case "IEND":
@@ -128,10 +136,18 @@ func createTextChunk(embed PngEmbed) []byte {
 	crc.Write(data)
 
 	chunk := bytes.NewBuffer(nil)
-	binary.Write(chunk, binary.BigEndian, uint32(len(data)))
-	chunk.Write([]byte(textChunkType))
-	chunk.Write(data)
-	binary.Write(chunk, binary.BigEndian, crc.Sum32())
+	if err := binary.Write(chunk, binary.BigEndian, uint32(len(data))); err != nil {
+		return nil, fmt.Errorf("error writing chunk length: %w", err)
+	}
+	if _, err := chunk.Write([]byte(textChunkType)); err != nil {
+		return nil, fmt.Errorf("error writing chunk type: %w", err)
+	}
+	if _, err := chunk.Write(data); err != nil {
+		return nil, fmt.Errorf("error writing chunk data: %w", err)
+	}
+	if err := binary.Write(chunk, binary.BigEndian, crc.Sum32()); err != nil {
+		return nil, fmt.Errorf("error writing CRC: %w", err)
+	}
 
 	return chunk.Bytes()
 }
diff --git a/pngmeta/metareader.go b/pngmeta/metareader.go
index df2a8d4..408af18 100644
--- a/pngmeta/metareader.go
+++ b/pngmeta/metareader.go
@@ -22,7 +22,6 @@ const (
 	writeHeader = "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"
 )
 
-var tEXtChunkDataSpecification = "%s\x00%s"
 
 type PngEmbed struct {
 	Key   string
-- 
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