Created replacement for StringBufferInputStream that properly encodes chars into bytes.

2026-04-05 00:00:01 -04:00 · 2013-09-04 13:23:17 +02:00
parent 4de927b657
commit 9a27f62dec
2 changed files with 213 additions and 0 deletions
--- a/sandbox/sandbox-common/src/main/java/com/twelvemonkeys/io/StringInputStream.java
+++ b/sandbox/sandbox-common/src/main/java/com/twelvemonkeys/io/StringInputStream.java
@@ -0,0 +1,87 @@
+package com.twelvemonkeys.io;
+
+import com.twelvemonkeys.lang.Validate;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
+
+/**
+ * An {@code InputStream} that reads bytes from a {@code String}.
+ *
+ * This class properly converts characters into bytes using a {@code Charset},
+ * unlike the deprecated {@link java.io.StringBufferInputStream}.
+ *
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ * @author last modified by $Author: haraldk$
+ * @version $Id: StringInputStream.java,v 1.0 03.09.13 10:19 haraldk Exp$
+ */
+public final class StringInputStream extends InputStream {
+
+    private final CharBuffer chars;
+    private final CharsetEncoder encoder;
+    private final ByteBuffer buffer;
+
+    public StringInputStream(final String string, final Charset charset) {
+        this(Validate.notNull(string, "string"), 0, string.length(), charset);
+    }
+
+    public StringInputStream(final String string, int offset, int length, final Charset charset) {
+        chars = CharBuffer.wrap(Validate.notNull(string, "string"), offset, offset + length);
+        encoder = Validate.notNull(charset, "charset").newEncoder();
+        buffer = ByteBuffer.allocate(256);
+        buffer.flip();
+    }
+
+    private boolean fillBuffer() {
+        buffer.clear();
+        encoder.encode(chars, buffer, chars.hasRemaining()); // TODO: Do we have to care about the result?
+        buffer.flip();
+
+        return buffer.hasRemaining();
+    }
+
+    private boolean ensureBuffer() {
+        return buffer.hasRemaining() || (chars.hasRemaining() && fillBuffer());
+    }
+
+    @Override
+    public int read() throws IOException {
+        if (!ensureBuffer()) {
+            return -1;
+        }
+
+        return buffer.get() & 0xff;
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        if (!ensureBuffer()) {
+            return -1;
+        }
+
+        int count = Math.min(buffer.remaining(), len);
+        buffer.get(b, off, count);
+        return count;
+    }
+
+    @Override
+    public long skip(long len) throws IOException {
+        if (!ensureBuffer()) {
+            return -1;
+        }
+
+        int count = (int) Math.min(buffer.remaining(), len);
+        int position = buffer.position();
+        buffer.position(position + count);
+        return count;
+    }
+
+    @Override
+    public int available() throws IOException {
+        return buffer.remaining();
+    }
+}