Merge pull request #352 from johnjaylward/ErrorMessagePositionFixes

Error message position fixes

CDL.java

@@ -70,9 +70,12 @@ public class CDL {
                 c = x.next();
                 if (c == q) {
                     //Handle escaped double-quote
-                    if(x.next() != '\"')
-                    {
+                    char nextC = x.next();
+                    if(nextC != '\"') {
+                        // if our quote was the end of the file, don't step
+                        if(nextC > 0) {
                             x.back();
+                        }
                         break;
                     }
                 }

JSONTokener.java

@@ -39,7 +39,7 @@ SOFTWARE.
  * @version 2014-05-03
  */
 public class JSONTokener {
-    /** current read character. */
+    /** current read character position on the current line. */
     private long character;
     /** flag to indicate if the end of the input has been found. */
     private boolean eof;
@@ -47,16 +47,18 @@ public class JSONTokener {
     private long index;
     /** current line of the input. */
     private long line;
-    /** previous index of the input. */
+    /** previous character read from the input. */
     private char previous;
     /** Reader for the input. */
     private final Reader reader;
     /** flag to indicate that a previous character was requested. */
     private boolean usePrevious;
+    /** the number of characters read in the previous line. */
+    private long characterPreviousLine;
 
 
     /**
-     * Construct a JSONTokener from a Reader.
+     * Construct a JSONTokener from a Reader. The caller must close the Reader.
      *
      * @param reader     A reader.
      */
@@ -69,12 +71,13 @@ public class JSONTokener {
         this.previous = 0;
         this.index = 0;
         this.character = 1;
+        this.characterPreviousLine = 0;
         this.line = 1;
     }
 
 
     /**
-     * Construct a JSONTokener from an InputStream.
+     * Construct a JSONTokener from an InputStream. The caller must close the input stream.
      * @param inputStream The source.
      */
     public JSONTokener(InputStream inputStream) {
@@ -103,12 +106,23 @@ public class JSONTokener {
         if (this.usePrevious || this.index <= 0) {
             throw new JSONException("Stepping back two steps is not supported");
         }
-        this.index -= 1;
-        this.character -= 1;
+        this.decrementIndexes();
         this.usePrevious = true;
         this.eof = false;
     }
 
+    /**
+     * Decrements the indexes for the {@link #back()} method based on the previous character read.
+     */
+    private void decrementIndexes() {
+        this.index--;
+        if(this.previous=='\r' || this.previous == '\n') {
+            this.line--;
+            this.character=this.characterPreviousLine ;
+        } else if(this.character > 0){
+            this.character--;
+        }
+    }
 
     /**
      * Get the hex value of a character (base16).
@@ -130,6 +144,8 @@ public class JSONTokener {
     }
 
     /**
+     * Checks if the end of the input has been reached.
+     *  
      * @return true if at the end of the file and we didn't step back
      */
     public boolean end() {
@@ -145,11 +161,24 @@ public class JSONTokener {
      *  or backward while checking for more data.
      */
     public boolean more() throws JSONException {
-        this.next();
-        if (this.end()) {
+        if(this.usePrevious) {
+            return true;
+        }
+        try {
+            this.reader.mark(1);
+        } catch (IOException e) {
+            throw new JSONException("Unable to preserve stream position", e);
+        }
+        try {
+            // -1 is EOF, but next() can not consume the null character '\0'
+            if(this.reader.read() <= 0) {
+                this.eof = true;
                 return false;
             }
-        this.back();
+            this.reader.reset();
+        } catch (IOException e) {
+            throw new JSONException("Unable to read the next character from the stream", e);
+        }
         return true;
     }
 
@@ -171,26 +200,39 @@ public class JSONTokener {
             } catch (IOException exception) {
                 throw new JSONException(exception);
             }
-
+        }
         if (c <= 0) { // End of stream
             this.eof = true;
-                c = 0;
-            }
-        }
-        this.index += 1;
-        if (this.previous == '\r') {
-            this.line += 1;
-            this.character = c == '\n' ? 0 : 1;
-        } else if (c == '\n') {
-            this.line += 1;
-            this.character = 0;
-        } else {
-            this.character += 1;
+            return 0;
         }
+        this.incrementIndexes(c);
         this.previous = (char) c;
         return this.previous;
     }
 
+    /**
+     * Increments the internal indexes according to the previous character
+     * read and the character passed as the current character.
+     * @param c the current character read.
+     */
+    private void incrementIndexes(int c) {
+        if(c > 0) {
+            this.index++;
+            if(c=='\r') {
+                this.line++;
+                this.characterPreviousLine = this.character;
+                this.character=0;
+            }else if (c=='\n') {
+                if(this.previous != '\r') {
+                    this.line++;
+                    this.characterPreviousLine = this.character;
+                }
+                this.character=0;
+            } else {
+                this.character++;
+            }
+        }
+    }
 
     /**
      * Consume the next character, and check that it matches a specified
@@ -202,9 +244,12 @@ public class JSONTokener {
     public char next(char c) throws JSONException {
         char n = this.next();
         if (n != c) {
+            if(n > 0) {
                 throw this.syntaxError("Expected '" + c + "' and instead saw '" +
                         n + "'");
             }
+            throw this.syntaxError("Expected '" + c + "' and instead saw ''");
+        }
         return n;
     }
 
@@ -432,13 +477,17 @@ public class JSONTokener {
             do {
                 c = this.next();
                 if (c == 0) {
+                    // in some readers, reset() may throw an exception if
+                    // the remaining portion of the input is greater than
+                    // the mark size (1,000,000 above).
                     this.reader.reset();
                     this.index = startIndex;
                     this.character = startCharacter;
                     this.line = startLine;
-                    return c;
+                    return 0;
                 }
             } while (c != to);
+            this.reader.mark(1);
         } catch (IOException exception) {
             throw new JSONException(exception);
         }
@@ -446,7 +495,6 @@ public class JSONTokener {
         return c;
     }
 
-
     /**
      * Make a JSONException to signal a syntax error.
      *

XMLTokener.java

@@ -64,11 +64,8 @@ public class XMLTokener extends JSONTokener {
         char         c;
         int          i;
         StringBuilder sb = new StringBuilder();
-        for (;;) {
+        while (more()) {
             c = next();
-            if (end()) {
-                throw syntaxError("Unclosed CDATA");
-            }
             sb.append(c);
             i = sb.length() - 3;
             if (i >= 0 && sb.charAt(i) == ']' &&
@@ -77,6 +74,7 @@ public class XMLTokener extends JSONTokener {
                 return sb.toString();
             }
         }
+        throw syntaxError("Unclosed CDATA");
     }
 
 
@@ -103,7 +101,10 @@ public class XMLTokener extends JSONTokener {
         }
         sb = new StringBuilder();
         for (;;) {
-            if (c == '<' || c == 0) {
+            if (c == 0) {
+                return sb.toString().trim();
+            }
+            if (c == '<') {
                 back();
                 return sb.toString().trim();
             }