fixed bigdecimal parser (#678)

Co-authored-by: Ferenc Csaky <[email protected]>

Author: ferenc-csaky

src/main/java/com/fasterxml/jackson/core/io/BigDecimalParser.java

@@ -8,28 +8,24 @@
 public final class BigDecimalParser {
 
     private final char[] chars;
-    private final int off;
     private final int len;
 
-    BigDecimalParser(char[] chars, int off, int len) {
+    BigDecimalParser(char[] chars) {
         this.chars = chars;
-        this.off = off;
-        this.len = len;
+        len = chars.length;
     }
 
     BigDecimal parse() throws NumberFormatException {
         try {
-            if (len < 500) {
-                return new BigDecimal(chars, off, len);
+            if (chars.length < 500) {
+                return new BigDecimal(chars);
             }
 
-            int splitLen = len / 10;
+            int splitLen = chars.length / 10;
             return parseBigDecimal(splitLen);
 
         } catch (NumberFormatException e) {
-            String val = new String(chars, off, len);
-
-            throw new NumberFormatException("Value \"" + val + "\" can not be represented as BigDecimal."
+            throw new NumberFormatException("Value \"" + new String(chars) + "\" can not be represented as BigDecimal."
                     + " Reason: " + e.getMessage());
         }
     }
@@ -43,7 +39,7 @@ private BigDecimal parseBigDecimal(int splitLen) {
         int dotIdx = -1;
         int scale = 0;
 
-        for (int i = off; i < len; i++) {
+        for (int i = 0; i < len; i++) {
             char c = chars[i];
             switch (c) {
             case '+':

src/main/java/com/fasterxml/jackson/core/io/NumberInput.java

@@ -316,12 +316,15 @@ public static BigDecimal parseBigDecimal(String s) throws NumberFormatException
         return parseBigDecimal(ch);
     }
 
-    public static BigDecimal parseBigDecimal(char[] ch) throws NumberFormatException {
-        return parseBigDecimal(ch, 0, ch.length);
+    public static BigDecimal parseBigDecimal(char[] ch, int off, int len) throws NumberFormatException {
+        char[] copy = new char[len];
+        System.arraycopy(ch, off, copy, 0, len);
+
+        return parseBigDecimal(copy);
     }
 
-    public static BigDecimal parseBigDecimal(char[] ch, int off, int len) throws NumberFormatException {
-        BigDecimalParser parser = new BigDecimalParser(ch, off, len);
+    public static BigDecimal parseBigDecimal(char[] ch) throws NumberFormatException {
+        BigDecimalParser parser = new BigDecimalParser(ch);
 
         return parser.parse();
     }