Merge pull request #75 from hkupty/logger-storage-improvements

Logger storage improvements

penna-core/src/main/java/penna/core/internals/StringNavigator.java

@@ -0,0 +1,78 @@
+package penna.core.internals;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Iterator;
+
+public class StringNavigator implements Iterator<StringNavigator.StringView> {
+    public static final int DOT = 0x2E;
+    public static final int DOLLAR = 0x24;
+    public final String base;
+    public int startIndex;
+    public int nextIndex;
+    public boolean hasNext = true;
+    public int symbol = DOT;
+
+
+    @Override
+    public boolean hasNext() {
+        return hasNext;
+    }
+
+    @Override
+    public StringView next() {
+        StringView view;
+        nextIndex = base.indexOf(symbol, startIndex);
+        if (nextIndex == -1 && symbol == DOT) {
+            symbol = DOLLAR;
+            nextIndex = base.indexOf(symbol, startIndex);
+        }
+        if (nextIndex == -1) {
+            hasNext = false;
+            view = new StringView(base, startIndex, base.length() - startIndex);
+        } else {
+            view = new StringView(base, startIndex, nextIndex - startIndex);
+            startIndex = nextIndex + 1;
+        }
+        return view;
+    }
+
+    public record StringView(String base, int startingPoint, int length) implements CharSequence {
+
+        @Override
+        public int length() {return length;}
+
+        @Override
+        public char charAt(int index) {
+            return base.charAt(startingPoint + index);
+        }
+
+        @Override
+        public @NotNull CharSequence subSequence(int start, int end) {
+            return base.subSequence(startingPoint + start, startingPoint + Math.min(end, length));
+        }
+
+        @Override
+        public @NotNull String toString() {
+            return base.substring(startingPoint, startingPoint + length);
+        }
+
+        public int indexCompare(String against) {
+            int diff = CharSequence.compare(this, against);
+            return Integer.signum(diff) + 1;
+        }
+    }
+
+    public StringNavigator(final String base) {
+        this.base = base;
+    }
+
+    public StringView chunk(int index) {
+        return null;
+    }
+
+    public int indexCompare(int index, String against) {
+        return -1;
+    }
+
+}