Consume less memory

src/main/java/com/jsoniter/IterImpl.java

@@ -5,15 +5,9 @@
 import com.jsoniter.spi.Slice;
 
 import java.io.IOException;
-import java.math.BigInteger;
 
 class IterImpl {
 
-    private static BigInteger maxLong = BigInteger.valueOf(Long.MAX_VALUE);
-    private static BigInteger minLong = BigInteger.valueOf(Long.MIN_VALUE);
-    private static BigInteger maxInt = BigInteger.valueOf(Integer.MAX_VALUE);
-    private static BigInteger minInt = BigInteger.valueOf(Integer.MIN_VALUE);
-
     public static final int readObjectFieldAsHash(JsonIterator iter) throws IOException {
         if (readByte(iter) != '"') {
             if (nextToken(iter) != '"') {

src/main/java/com/jsoniter/IterImplNumber.java

@@ -35,8 +35,8 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 
 class IterImplNumber {
 
-    final static int[] intDigits = new int[127];
-    final static int[] floatDigits = new int[127];
+    final static byte[] intDigits = new byte[127];
+    final static byte[] floatDigits = new byte[127];
     final static int END_OF_NUMBER = -2;
     final static int DOT_IN_NUMBER = -3;
     final static int INVALID_CHAR_FOR_NUMBER = -1;
@@ -51,8 +51,8 @@ class IterImplNumber {
             intDigits[i] = INVALID_CHAR_FOR_NUMBER;
         }
         for (int i = '0'; i <= '9'; ++i) {
-            floatDigits[i] = (i - '0');
-            intDigits[i] = (i - '0');
+            floatDigits[i] = (byte) (i - '0');
+            intDigits[i] = (byte) (i - '0');
         }
         floatDigits[','] = END_OF_NUMBER;
         floatDigits[']'] = END_OF_NUMBER;

src/main/java/com/jsoniter/IterImplString.java

@@ -35,22 +35,14 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 
 class IterImplString {
 
-    final static int[] hexDigits = new int['f' + 1];
-
-    static {
-        for (int i = 0; i < hexDigits.length; i++) {
-            hexDigits[i] = -1;
-        }
-        for (int i = '0'; i <= '9'; ++i) {
-            hexDigits[i] = (i - '0');
-        }
-        for (int i = 'a'; i <= 'f'; ++i) {
-            hexDigits[i] = ((i - 'a') + 10);
-        }
-        for (int i = 'A'; i <= 'F'; ++i) {
-            hexDigits[i] = ((i - 'A') + 10);
-        }
-    }
+    private final static byte[] hexDigits = {
+            /* 48 unused characters skipped */
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, // decimal digits
+            -1, -1, -1, -1, -1, -1, -1,
+            10, 11, 12, 13, 14, 15,       // hexadecimal digits, lowercase
+            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+            10, 11, 12, 13, 14, 15        // hexadecimal digits, uppercase
+    };
 
     public static final String readString(JsonIterator iter) throws IOException {
         byte c = IterImpl.nextToken(iter);
@@ -95,10 +87,17 @@ private static int parse(JsonIterator iter) throws IOException {
     }
 
     public static int translateHex(final byte b) {
-        int val = hexDigits[b];
+        int val;
+        try {
+            val = hexDigits[b - '0'];
+        } catch (ArrayIndexOutOfBoundsException e) {
+            throw new IndexOutOfBoundsException(b + " is not valid hex digit");
+        }
+
         if (val == -1) {
             throw new IndexOutOfBoundsException(b + " is not valid hex digit");
         }
+
         return val;
     }
 

src/main/java/com/jsoniter/JsonIterator.java

@@ -16,9 +16,44 @@
 
 public class JsonIterator implements Closeable {
 
+    // We have our own constants and a dictionary of size 256 bytes,
+    // while ValueType[256] is 1024 bytes on 32-bit system.
+    // If no one will call `whatIsNext`, ValueType class won't ever be loaded.
+    private static final byte T_INVALID = -1;
+    private static final byte T_STRING = 1;
+    private static final byte T_NUMBER = 2;
+    private static final byte T_NULL = 0;
+    private static final byte T_BOOLEAN = 3;
+    private static final byte T_ARRAY = 4;
+    private static final byte T_OBJECT = 5;
+    private static final byte[] types;
+    static {
+        byte[] _types = new byte[256];
+        for (int i = 0; i < _types.length; i++) {
+            _types[i] = T_INVALID;
+        }
+        _types['"'] = T_STRING;
+        _types['-'] = T_NUMBER;
+        _types['0'] = T_NUMBER;
+        _types['1'] = T_NUMBER;
+        _types['2'] = T_NUMBER;
+        _types['3'] = T_NUMBER;
+        _types['4'] = T_NUMBER;
+        _types['5'] = T_NUMBER;
+        _types['6'] = T_NUMBER;
+        _types['7'] = T_NUMBER;
+        _types['8'] = T_NUMBER;
+        _types['9'] = T_NUMBER;
+        _types['t'] = T_BOOLEAN;
+        _types['f'] = T_BOOLEAN;
+        _types['n'] = T_NULL;
+        _types['['] = T_ARRAY;
+        _types['{'] = T_OBJECT;
+        types = _types;
+    }
+
     public Config configCache;
     private static boolean isStreamingEnabled = false;
-    final static ValueType[] valueTypes = new ValueType[256];
     InputStream in;
     byte[] buf;
     int head;
@@ -30,29 +65,6 @@ public class JsonIterator implements Closeable {
     char[] reusableChars = new char[32];
     Object existingObject = null; // the object should be bind to next
 
-    static {
-        for (int i = 0; i < valueTypes.length; i++) {
-            valueTypes[i] = ValueType.INVALID;
-        }
-        valueTypes['"'] = ValueType.STRING;
-        valueTypes['-'] = ValueType.NUMBER;
-        valueTypes['0'] = ValueType.NUMBER;
-        valueTypes['1'] = ValueType.NUMBER;
-        valueTypes['2'] = ValueType.NUMBER;
-        valueTypes['3'] = ValueType.NUMBER;
-        valueTypes['4'] = ValueType.NUMBER;
-        valueTypes['5'] = ValueType.NUMBER;
-        valueTypes['6'] = ValueType.NUMBER;
-        valueTypes['7'] = ValueType.NUMBER;
-        valueTypes['8'] = ValueType.NUMBER;
-        valueTypes['9'] = ValueType.NUMBER;
-        valueTypes['t'] = ValueType.BOOLEAN;
-        valueTypes['f'] = ValueType.BOOLEAN;
-        valueTypes['n'] = ValueType.NULL;
-        valueTypes['['] = ValueType.ARRAY;
-        valueTypes['{'] = ValueType.OBJECT;
-    }
-
     private JsonIterator(InputStream in, byte[] buf, int head, int tail) {
         this.in = in;
         this.buf = buf;
@@ -246,13 +258,13 @@ public final BigDecimal readBigDecimal() throws IOException {
 
     public final BigInteger readBigInteger() throws IOException {
         // skip whitespace by read next
-        ValueType valueType = whatIsNext();
-        if (valueType == ValueType.NULL) {
+        byte type = whatsNext();
+        if (type == T_NULL) {
             skip();
             return null;
         }
-        if (valueType != ValueType.NUMBER) {
-            throw reportError("readBigDecimal", "not number");
+        if (type != T_NUMBER) {
+            throw reportError("readNumber", "not number");
         }
         IterImplForStreaming.numberChars numberChars = IterImplForStreaming.readNumber(this);
         return new BigInteger(new String(numberChars.chars, 0, numberChars.charsLength));
@@ -266,31 +278,33 @@ public final Any readAny() throws IOException {
         }
     }
 
-    private final static ReadArrayCallback fillArray = new ReadArrayCallback() {
+    private static final class ReadArrayObjectCallback implements ReadArrayCallback, ReadObjectCallback {
+
+        static final ReadArrayObjectCallback INSTANCE = new ReadArrayObjectCallback();
+
+        private ReadArrayObjectCallback() {}
+
         @Override
         public boolean handle(JsonIterator iter, Object attachment) throws IOException {
             List list = (List) attachment;
             list.add(iter.read());
             return true;
         }
-    };
-
-    private final static ReadObjectCallback fillObject = new ReadObjectCallback() {
         @Override
         public boolean handle(JsonIterator iter, String field, Object attachment) throws IOException {
             Map map = (Map) attachment;
             map.put(field, iter.read());
             return true;
         }
-    };
+    }
 
     public final Object read() throws IOException {
         try {
-            ValueType valueType = whatIsNext();
-            switch (valueType) {
-                case STRING:
+            byte type = whatsNext();
+            switch (type) {
+                case T_STRING:
                     return readString();
-                case NUMBER:
+                case T_NUMBER:
                     IterImplForStreaming.numberChars numberChars = IterImplForStreaming.readNumber(this);
                     String numberStr = new String(numberChars.chars, 0, numberChars.charsLength);
                     Double number = Double.valueOf(numberStr);
@@ -306,21 +320,21 @@ public final Object read() throws IOException {
                         return longNumber;
                     }
                     return number;
-                case NULL:
+                case T_NULL:
                     IterImpl.skipFixedBytes(this, 4);
                     return null;
-                case BOOLEAN:
+                case T_BOOLEAN:
                     return readBoolean();
-                case ARRAY:
+                case T_ARRAY:
                     ArrayList list = new ArrayList(4);
-                    readArrayCB(fillArray, list);
+                    readArrayCB(ReadArrayObjectCallback.INSTANCE, list);
                     return list;
-                case OBJECT:
+                case T_OBJECT:
                     Map map = new HashMap(4);
-                    readObjectCB(fillObject, map);
+                    readObjectCB(ReadArrayObjectCallback.INSTANCE, map);
                     return map;
                 default:
-                    throw reportError("read", "unexpected value type: " + valueType);
+                    throw reportError("read", "unexpected value type: " + type);
             }
         } catch (ArrayIndexOutOfBoundsException e) {
             throw reportError("read", "premature end");
@@ -390,11 +404,17 @@ public final Object read(Type type) throws IOException {
     }
 
     public ValueType whatIsNext() throws IOException {
-        ValueType valueType = valueTypes[IterImpl.nextToken(this)];
+        ValueType valueType = ValueType.ofCharacter(IterImpl.nextToken(this));
         unreadByte();
         return valueType;
     }
 
+    private byte whatsNext() throws IOException {
+        byte type = types[IterImpl.nextToken(this)];
+        unreadByte();
+        return type;
+    }
+
     public void skip() throws IOException {
         IterImplSkip.skip(this);
     }

src/main/java/com/jsoniter/ValueType.java

@@ -7,5 +7,35 @@ public enum ValueType {
     NULL,
     BOOLEAN,
     ARRAY,
-    OBJECT
+    OBJECT;
+
+    private static final ValueType[] valueTypes = new ValueType[256];
+
+    static {
+        for (int i = 0; i < valueTypes.length; i++) {
+            valueTypes[i] = ValueType.INVALID;
+        }
+        valueTypes['"'] = ValueType.STRING;
+        valueTypes['-'] = ValueType.NUMBER;
+        valueTypes['0'] = ValueType.NUMBER;
+        valueTypes['1'] = ValueType.NUMBER;
+        valueTypes['2'] = ValueType.NUMBER;
+        valueTypes['3'] = ValueType.NUMBER;
+        valueTypes['4'] = ValueType.NUMBER;
+        valueTypes['5'] = ValueType.NUMBER;
+        valueTypes['6'] = ValueType.NUMBER;
+        valueTypes['7'] = ValueType.NUMBER;
+        valueTypes['8'] = ValueType.NUMBER;
+        valueTypes['9'] = ValueType.NUMBER;
+        valueTypes['t'] = ValueType.BOOLEAN;
+        valueTypes['f'] = ValueType.BOOLEAN;
+        valueTypes['n'] = ValueType.NULL;
+        valueTypes['['] = ValueType.ARRAY;
+        valueTypes['{'] = ValueType.OBJECT;
+    }
+
+    public static ValueType ofCharacter(byte character) {
+        return valueTypes[character];
+    }
+
 }

src/main/java/com/jsoniter/extra/Base64.java

@@ -5,6 +5,7 @@
 import com.jsoniter.output.JsonStream;
 
 import java.io.IOException;
+import java.io.UnsupportedEncodingException;
 import java.util.Arrays;
 
 /** A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance
@@ -76,12 +77,18 @@
  */
 
 abstract class Base64 {
-    private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
-    static final byte[] BA;
-    static final int[] IA = new int[256];
+    private static final byte[] CA;
+    private static final byte[] BA;
+    private static final byte[] IA = new byte[256];
     static {
-        Arrays.fill(IA, -1);
-        for (int i = 0, iS = CA.length; i < iS; i++) {
+        Arrays.fill(IA, (byte) -1);
+        try {
+            CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".getBytes("US-ASCII");
+        } catch (UnsupportedEncodingException e) {
+            throw new AssertionError(e);
+        }
+
+        for (byte i = 0, iS = (byte) CA.length; i < iS; i++) {
             IA[CA[i]] = i;
         }
         IA['='] = 0;
@@ -103,10 +110,10 @@ static int encodeToChar(byte[] sArr, char[] dArr, final int start) {
             int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);
 
             // Encode the int into four chars
-            dArr[d++] = CA[(i >>> 18) & 0x3f];
-            dArr[d++] = CA[(i >>> 12) & 0x3f];
-            dArr[d++] = CA[(i >>> 6) & 0x3f];
-            dArr[d++] = CA[i & 0x3f];
+            dArr[d++] = (char) CA[(i >>> 18) & 0x3f];
+            dArr[d++] = (char) CA[(i >>> 12) & 0x3f];
+            dArr[d++] = (char) CA[(i >>> 6) & 0x3f];
+            dArr[d++] = (char) CA[i & 0x3f];
         }
 
         // Pad and encode last bits if source isn't even 24 bits.
@@ -116,9 +123,9 @@ static int encodeToChar(byte[] sArr, char[] dArr, final int start) {
             int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
 
             // Set last four chars
-            dArr[start + dLen - 4] = CA[i >> 12];
-            dArr[start + dLen - 3] = CA[(i >>> 6) & 0x3f];
-            dArr[start + dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';
+            dArr[start + dLen - 4] = (char) CA[i >> 12];
+            dArr[start + dLen - 3] = (char) CA[(i >>> 6) & 0x3f];
+            dArr[start + dLen - 2] = left == 2 ? (char) CA[i & 0x3f] : '=';
             dArr[start + dLen - 1] = '=';
         }