From 76a9ff1122b7579a09fdbcabf471d936d82ebab2 Mon Sep 17 00:00:00 2001
From: Harald Kuhr <harald.kuhr@gmail.com>
Date: Tue, 8 Feb 2022 11:19:38 +0100
Subject: [PATCH] #660: Attempt at making the comment parsing more
 Windows-friendly...

(cherry picked from commit 60eab8170934aacee46a8ee33d65c1748939a184)
---
 .../imageio/plugins/pnm/PNMHeaderParser.java  | 30 ++++++++++++++++---
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMHeaderParser.java b/imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMHeaderParser.java
index af2506b8..e4db9b0c 100755
--- a/imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMHeaderParser.java
+++ b/imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMHeaderParser.java
@@ -30,8 +30,11 @@
 
 package com.twelvemonkeys.imageio.plugins.pnm;
 
+import com.twelvemonkeys.io.FastByteArrayOutputStream;
+
 import javax.imageio.IIOException;
 import javax.imageio.stream.ImageInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -76,11 +79,11 @@ final class PNMHeaderParser extends HeaderParser {
             tokenBuffer.delete(0, tokenBuffer.length());
 
             while (tokenBuffer.length() < 16) {
-                char read = (char) input.readByte();
+                byte read = input.readByte();
 
                 if (read == '#') {
                     // Read rest of the line as comment
-                    String comment = input.readLine();
+                    String comment = readComment(input);
 
                     if (!comment.trim().isEmpty()) {
                         comments.add(comment);
@@ -88,13 +91,13 @@ final class PNMHeaderParser extends HeaderParser {
 
                     break;
                 }
-                else if (Character.isWhitespace(read)) {
+                else if (Character.isWhitespace((char) read)) {
                     if (tokenBuffer.length() > 0) {
                         break;
                     }
                 }
                 else {
-                    tokenBuffer.append(read);
+                    tokenBuffer.append((char) read);
                 }
             }
 
@@ -119,4 +122,23 @@ final class PNMHeaderParser extends HeaderParser {
 
         return new PNMHeader(fileType, tupleType, width, height, tupleType.getSamplesPerPixel(), maxSample, comments);
     }
+
+    private static String readComment(final ImageInputStream input) throws IOException {
+        ByteArrayOutputStream commentBuffer = new FastByteArrayOutputStream(128);
+
+        int read;
+        do {
+            switch (read = input.read()) {
+                case -1:
+                case '\n':
+                case '\r':
+                    read = -1;
+                    break;
+                default:
+                    commentBuffer.write(read);
+            }
+        } while (read != -1);
+
+        return commentBuffer.toString("UTF8");
+    }
 }