Add ImString resize support

imgui-binding/src/main/java/imgui/ImString.java

@@ -1,20 +1,30 @@
 package imgui;
 
-import java.util.Arrays;
+import java.util.Objects;
 
+/**
+ * Wrapper for {@link String} to use inside of ImGui input widgets.
+ */
 public final class ImString {
-    private static final int DEFAULT_SIZE = 100;
+    private static final short DEFAULT_LENGTH = 100;
+    private static final short CARET_LEN = 1;
+    private static final short DEFAULT_RESIZE = 10;
+
+    public final ImGuiInputTextData inputData = new ImGuiInputTextData();
+    /**
+     * String will be resized to the value equal to a new size plus this resize factor.
+     */
+    public int resizeFactor = DEFAULT_RESIZE;
 
-    ImGuiInputTextData inputData = new ImGuiInputTextData();
     byte[] data;
-    private String text;
+    private String text = "";
 
     public ImString() {
-        this(DEFAULT_SIZE);
+        this(DEFAULT_LENGTH);
     }
 
-    public ImString(int size) {
-        data = new byte[size];
+    public ImString(int length) {
+        data = new byte[length + CARET_LEN];
     }
 
     public ImString(String text) {
@@ -22,8 +32,8 @@ public final class ImString {
         set(text);
     }
 
-    public ImString(String text, int size) {
-        this(size);
+    public ImString(String text, int length) {
+        this(length);
         set(text);
     }
 
@@ -36,11 +46,38 @@ public final class ImString {
     }
 
     public void set(String value) {
-        inputData.size = value.length();
-        text = value;
-        for (int i = 0; i < inputData.size; i++) {
-            data[i] = (byte) value.charAt(i);
+        set(value.getBytes());
+    }
+
+    public void set(String value, boolean resize) {
+        byte[] str = value.getBytes();
+        if (resize && data.length - CARET_LEN < str.length) {
+            data = new byte[str.length + resizeFactor + CARET_LEN];
         }
+        set(str);
+    }
+
+    /**
+     * Get the length of the text inside of the data buffer.
+     * @return length of the text inside of the data buffer
+     */
+    public int getLength() {
+        return get().length();
+    }
+
+    /**
+     * Get the size of the data buffer. Buffer size will always have '+1' to its size, since it's used by the Dear ImGui to draw a caret.
+     * @return size of the data buffer
+     */
+    public int getBufferSize() {
+        return data.length;
+    }
+
+    private void set(byte[] str) {
+        int len = Math.min(str.length, data.length);
+        System.arraycopy(str, 0, data, 0, len);
+        inputData.isDirty = true;
+        inputData.size = len;
     }
 
     @Override
@@ -53,11 +90,11 @@ public final class ImString {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         ImString imString = (ImString) o;
-        return Arrays.equals(data, imString.data);
+        return Objects.equals(text, imString.text);
     }
 
     @Override
     public int hashCode() {
-        return Arrays.hashCode(data);
+        return text.hashCode();
     }
 }