Implemented info hash extraction

Author: robothaver

src/main/java/com/robothaver/torrentfileparser/TorrentFileParser.java

@@ -10,6 +10,7 @@ public class TorrentFileParser {
     private final byte[] bytes;
     private int iterator = 0;
     private TorrentBuilder torrentBuilder = null;
+    private int infoDictStartIndex = -1;
 
     public TorrentFileParser(byte[] bytes) {
         this.bytes = bytes;
@@ -63,6 +64,9 @@ private Map<String, Object> parseDict() throws MalformedTorrentFileException {
             Object parseValue = parse();
             if (key == null) {
                 key = String.valueOf(parseValue);
+                if (key.equals("info")) {
+                    infoDictStartIndex = iterator;
+                }
             } else {
                 map.put(key, parseValue);
                 if (torrentBuilder != null) {
@@ -71,6 +75,9 @@ private Map<String, Object> parseDict() throws MalformedTorrentFileException {
                 key = null;
             }
         }
+        if (infoDictStartIndex != -1 && torrentBuilder != null) {
+            torrentBuilder.setInfoHash(Arrays.copyOfRange(bytes, infoDictStartIndex, iterator));
+        }
         iterator++; // Skipping closing e
         return map;
     }

src/main/java/com/robothaver/torrentfileparser/domain/Torrent.java

@@ -13,6 +13,7 @@ public class Torrent {
     private Long totalLength = 0L;
     private String pieces;
     private final List<TorrentFile> files = new ArrayList<>();
+    private String infoHash;
 
     // Optional fields
     private List<List<String>> announceList = null;
@@ -139,6 +140,14 @@ public void setAzureusProperties(Map<String, Object> azureusProperties) {
         this.azureusProperties = azureusProperties;
     }
 
+    public String getInfoHash() {
+        return infoHash;
+    }
+
+    public void setInfoHash(String infoHash) {
+        this.infoHash = infoHash;
+    }
+
     @Override
     public String toString() {
         return "Torrent{" +
@@ -149,6 +158,7 @@ public String toString() {
                 ", isPrivate=" + isPrivate +
                 ", totalLength=" + totalLength +
                 ", files=" + files +
+                ", infoHash='" + infoHash + '\'' +
                 ", announceList=" + announceList +
                 ", creator='" + creator + '\'' +
                 ", creationDate=" + creationDate +

src/main/java/com/robothaver/torrentfileparser/domain/TorrentBuilder.java

@@ -1,5 +1,8 @@
 package com.robothaver.torrentfileparser.domain;
 
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.HexFormat;
 import java.util.List;
 import java.util.Map;
 
@@ -14,30 +17,42 @@ public void processKeyValue(String key, Object value) {
             case "announce-list" -> torrent.setAnnounceList((List<List<String>>) value);
             case "azureus_properties" -> torrent.setAzureusProperties((Map<String, Object>) value);
             case "created by" -> torrent.setCreator(String.valueOf(value));
-            case "creation date" -> torrent.setCreationDate((Long) value);
+            case "creation date" -> torrent.setCreationDate((long) value);
             case "encoding" -> torrent.setEncoding(String.valueOf(value));
             case "files" -> torrent.setSingleFile(false);
             case "length" -> {
-                lastLength = (Long) value;
+                lastLength = (long) value;
                 torrent.setTotalLength(torrent.getTotalLength() + lastLength);
             }
             case "path" -> torrent.getFiles().add(new TorrentFile(lastLength, formatFilePath(String.valueOf(value))));
-            case "piece length" -> torrent.setPieceLength((Long) value);
+            case "piece length" -> torrent.setPieceLength((long) value);
             case "source" -> torrent.setSource(String.valueOf(value));
             case "pieces" -> torrent.setPieces(String.valueOf(value));
             case "comment" -> torrent.setComment(String.valueOf(value));
-            case "private" -> {
-                boolean isPrivate = (Long) value == 1;
-                torrent.setPrivate(isPrivate);
-            }
+            case "private" -> torrent.setPrivate((long) value == 1);
+        }
+    }
+
+    public void setInfoHash(byte[] infoBytes) {
+        try {
+            torrent.setInfoHash(getSHAsum(infoBytes));
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);
         }
     }
 
+    private String getSHAsum(byte[] input) throws NoSuchAlgorithmException {
+        MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");
+        return byteArrayToHex(messageDigest.digest(input));
+    }
+
+    private String byteArrayToHex(byte[] bytes) {
+        HexFormat hex = HexFormat.of();
+        return hex.formatHex(bytes);
+    }
+
     private String formatFilePath(String path) {
-        return path
-                .replace("[", "")
-                .replace("]", "")
-                .replace(", ", "/");
+        return path.replace("[", "").replace("]", "").replace(", ", "/");
     }
 
     public Torrent getTorrent() {