Adds Integer.toString emulation

teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TAbstractStringBuilder.java

@@ -66,13 +66,17 @@ class TAbstractStringBuilder extends TObject implements TSerializable, TCharSequ
         return this;
     }
 
-    protected TAbstractStringBuilder append(int value) {
+    TAbstractStringBuilder append(int value) {
+        return append(value, 10);
+    }
+
+    TAbstractStringBuilder append(int value, int radix) {
         boolean positive = true;
         if (value < 0) {
             positive = false;
             value = -value;
         }
-        if (value < 10) {
+        if (value < radix) {
             if (!positive) {
                 ensureCapacity(length + 2);
                 buffer[length++] = '-';
@@ -81,10 +85,12 @@ class TAbstractStringBuilder extends TObject implements TSerializable, TCharSequ
             }
             buffer[length++] = (char)('0' + value);
         } else {
-            int pos = 10;
+            int pos = 1;
             int sz = 1;
-            while (pos < 1000000000 && pos * 10 <= value) {
+            int valueCopy = value;
-                pos *= 10;
+            while (valueCopy > radix) {
+                pos *= radix;
+                valueCopy /= radix;
                 ++sz;
             }
             if (!positive) {
@@ -95,9 +101,9 @@ class TAbstractStringBuilder extends TObject implements TSerializable, TCharSequ
                 buffer[length++] = '-';
             }
             while (pos > 0) {
-                buffer[length++] = (char)('0' + value / pos);
+                buffer[length++] = TCharacter.forDigit(value / pos, radix);
                 value %= pos;
-                pos /= 10;
+                pos /= radix;
             }
         }
         return this;

teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java

@@ -64,6 +64,13 @@ public class TCharacter {
         return -1;
     }
 
+    public static char forDigit(int digit, int radix) {
+        if (radix < MIN_RADIX || radix > MAX_RADIX || digit >= radix) {
+            return '\0';
+        }
+        return digit < 10 ? (char)('0' + digit) : (char)('a' + digit - 10);
+    }
+
     private static int[] getDigitMapping() {
         if (digitMapping == null) {
             digitMapping = UnicodeHelper.decodeIntByte(obtainDigitMapping());

teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TInteger.java

@@ -34,6 +34,13 @@ public class TInteger extends TNumber implements TComparable<TInteger> {
         this(parseInt(s));
     }
 
+    public static TString toString(int i, int radix) {
+        if (radix < MIN_VALUE || radix > MAX_VALUE) {
+            radix = 10;
+        }
+        return TString.wrap(new TAbstractStringBuilder(20).append(i, radix).toString());
+    }
+
     @Override
     public int compareTo(TInteger other) {
         return compare(value, other.value);

teavm-classlib/src/test/java/org/teavm/classlib/java/lang/IntegerTest.java

@@ -45,4 +45,11 @@ public class IntegerTest {
     public void rejectsIntegerWithDigitsOutOfRadix() {
         Integer.parseInt("99", 8);
     }
+
+    @Test
+    public void writesInteger() {
+        assertEquals("473", Integer.toString(473, 10));
+        assertEquals("-ff", Integer.toString(-255, 16));
+        assertEquals("kona", Integer.toString(411787, 27));
+    }
 }