New SCL completion implementation

[simantics/platform.git] / bundles / org.simantics.scl.compiler / src / org / simantics / scl / compiler / completions / parsing / SubstringReader.java

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/completions/parsing/SubstringReader.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/completions/parsing/SubstringReader.java
new file mode 100644 (file)
index 0000000..b74a0b3
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/completions/parsing/SubstringReader.java
@@ -0,0 +1,74 @@
+package org.simantics.scl.compiler.completions.parsing;
+
+import java.io.IOException;
+import java.io.Reader;
+
+/**
+ * Based on java.io.StringReader.
+ */
+
+public class SubstringReader extends Reader {
+
+    private String str;
+    private int end;
+    private int pos;
+    private int mark;
+
+    public SubstringReader(String str, int begin, int end) {
+        this.str = str;
+        this.pos = begin;
+        this.mark = begin;
+        this.end = end;
+    }
+
+    public int read() throws IOException {
+        if (pos >= end)
+            return -1;
+        return str.charAt(pos++);
+    }
+
+    public int read(char cbuf[], int off, int len) throws IOException {
+        if ((off < 0) || (off > cbuf.length) || (len < 0) ||
+                ((off + len) > cbuf.length) || ((off + len) < 0))
+            throw new IndexOutOfBoundsException();
+        else if (len == 0)
+            return 0;
+        if (pos >= end)
+            return -1;
+        int n = Math.min(end - pos, len);
+        str.getChars(pos, pos + n, cbuf, off);
+        pos += n;
+        return n;
+    }
+
+    public long skip(long ns) throws IOException {
+        if (pos >= end)
+            return 0;
+        // Bound skip by beginning and end of the source
+        long n = Math.min(end - pos, ns);
+        n = Math.max(-pos, n);
+        pos += n;
+        return n;
+    }
+
+    public boolean ready() throws IOException {
+        return true;
+    }
+
+    public boolean markSupported() {
+        return true;
+    }
+
+    public void mark(int readAheadLimit) throws IOException {
+        if (readAheadLimit < 0)
+            throw new IllegalArgumentException("Read-ahead limit < 0");
+        mark = pos;
+    }
+
+    public void reset() throws IOException {
+        pos = mark;
+    }
+
+    public void close() {
+    }
+}