--- /dev/null
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.dexgen.util;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.StringWriter;
+import java.io.Writer;
+
+/**
+ * Class that takes a combined output destination and provides two
+ * output writers, one of which ends up writing to the left column and
+ * one which goes on the right.
+ */
+public final class TwoColumnOutput {
+ /** {@code non-null;} underlying writer for final output */
+ private final Writer out;
+
+ /** {@code > 0;} the left column width */
+ private final int leftWidth;
+
+ /** {@code non-null;} pending left column output */
+ private final StringBuffer leftBuf;
+
+ /** {@code non-null;} pending right column output */
+ private final StringBuffer rightBuf;
+
+ /** {@code non-null;} left column writer */
+ private final IndentingWriter leftColumn;
+
+ /** {@code non-null;} right column writer */
+ private final IndentingWriter rightColumn;
+
+ /**
+ * Turns the given two strings (with widths) and spacer into a formatted
+ * two-column string.
+ *
+ * @param s1 {@code non-null;} first string
+ * @param width1 {@code > 0;} width of the first column
+ * @param spacer {@code non-null;} spacer string
+ * @param s2 {@code non-null;} second string
+ * @param width2 {@code > 0;} width of the second column
+ * @return {@code non-null;} an appropriately-formatted string
+ */
+ public static String toString(String s1, int width1, String spacer,
+ String s2, int width2) {
+ int len1 = s1.length();
+ int len2 = s2.length();
+
+ StringWriter sw = new StringWriter((len1 + len2) * 3);
+ TwoColumnOutput twoOut =
+ new TwoColumnOutput(sw, width1, width2, spacer);
+
+ try {
+ twoOut.getLeft().write(s1);
+ twoOut.getRight().write(s2);
+ } catch (IOException ex) {
+ throw new RuntimeException("shouldn't happen", ex);
+ }
+
+ twoOut.flush();
+ return sw.toString();
+ }
+
+ /**
+ * Constructs an instance.
+ *
+ * @param out {@code non-null;} writer to send final output to
+ * @param leftWidth {@code > 0;} width of the left column, in characters
+ * @param rightWidth {@code > 0;} width of the right column, in characters
+ * @param spacer {@code non-null;} spacer string to sit between the two columns
+ */
+ public TwoColumnOutput(Writer out, int leftWidth, int rightWidth,
+ String spacer) {
+ if (out == null) {
+ throw new NullPointerException("out == null");
+ }
+
+ if (leftWidth < 1) {
+ throw new IllegalArgumentException("leftWidth < 1");
+ }
+
+ if (rightWidth < 1) {
+ throw new IllegalArgumentException("rightWidth < 1");
+ }
+
+ if (spacer == null) {
+ throw new NullPointerException("spacer == null");
+ }
+
+ StringWriter leftWriter = new StringWriter(1000);
+ StringWriter rightWriter = new StringWriter(1000);
+
+ this.out = out;
+ this.leftWidth = leftWidth;
+ this.leftBuf = leftWriter.getBuffer();
+ this.rightBuf = rightWriter.getBuffer();
+ this.leftColumn = new IndentingWriter(leftWriter, leftWidth);
+ this.rightColumn =
+ new IndentingWriter(rightWriter, rightWidth, spacer);
+ }
+
+ /**
+ * Constructs an instance.
+ *
+ * @param out {@code non-null;} stream to send final output to
+ * @param leftWidth {@code >= 1;} width of the left column, in characters
+ * @param rightWidth {@code >= 1;} width of the right column, in characters
+ * @param spacer {@code non-null;} spacer string to sit between the two columns
+ */
+ public TwoColumnOutput(OutputStream out, int leftWidth, int rightWidth,
+ String spacer) {
+ this(new OutputStreamWriter(out), leftWidth, rightWidth, spacer);
+ }
+
+ /**
+ * Gets the writer to use to write to the left column.
+ *
+ * @return {@code non-null;} the left column writer
+ */
+ public Writer getLeft() {
+ return leftColumn;
+ }
+
+ /**
+ * Gets the writer to use to write to the right column.
+ *
+ * @return {@code non-null;} the right column writer
+ */
+ public Writer getRight() {
+ return rightColumn;
+ }
+
+ /**
+ * Flushes the output. If there are more lines of pending output in one
+ * column, then the other column will get filled with blank lines.
+ */
+ public void flush() {
+ try {
+ appendNewlineIfNecessary(leftBuf, leftColumn);
+ appendNewlineIfNecessary(rightBuf, rightColumn);
+ outputFullLines();
+ flushLeft();
+ flushRight();
+ } catch (IOException ex) {
+ throw new RuntimeException(ex);
+ }
+ }
+
+ /**
+ * Outputs to the final destination as many full line pairs as
+ * there are in the pending output, removing those lines from
+ * their respective buffers. This method terminates when at
+ * least one of the two column buffers is empty.
+ */
+ private void outputFullLines() throws IOException {
+ for (;;) {
+ int leftLen = leftBuf.indexOf("\n");
+ if (leftLen < 0) {
+ return;
+ }
+
+ int rightLen = rightBuf.indexOf("\n");
+ if (rightLen < 0) {
+ return;
+ }
+
+ if (leftLen != 0) {
+ out.write(leftBuf.substring(0, leftLen));
+ }
+
+ if (rightLen != 0) {
+ writeSpaces(out, leftWidth - leftLen);
+ out.write(rightBuf.substring(0, rightLen));
+ }
+
+ out.write('\n');
+
+ leftBuf.delete(0, leftLen + 1);
+ rightBuf.delete(0, rightLen + 1);
+ }
+ }
+
+ /**
+ * Flushes the left column buffer, printing it and clearing the buffer.
+ * If the buffer is already empty, this does nothing.
+ */
+ private void flushLeft() throws IOException {
+ appendNewlineIfNecessary(leftBuf, leftColumn);
+
+ while (leftBuf.length() != 0) {
+ rightColumn.write('\n');
+ outputFullLines();
+ }
+ }
+
+ /**
+ * Flushes the right column buffer, printing it and clearing the buffer.
+ * If the buffer is already empty, this does nothing.
+ */
+ private void flushRight() throws IOException {
+ appendNewlineIfNecessary(rightBuf, rightColumn);
+
+ while (rightBuf.length() != 0) {
+ leftColumn.write('\n');
+ outputFullLines();
+ }
+ }
+
+ /**
+ * Appends a newline to the given buffer via the given writer, but
+ * only if it isn't empty and doesn't already end with one.
+ *
+ * @param buf {@code non-null;} the buffer in question
+ * @param out {@code non-null;} the writer to use
+ */
+ private static void appendNewlineIfNecessary(StringBuffer buf,
+ Writer out)
+ throws IOException {
+ int len = buf.length();
+
+ if ((len != 0) && (buf.charAt(len - 1) != '\n')) {
+ out.write('\n');
+ }
+ }
+
+ /**
+ * Writes the given number of spaces to the given writer.
+ *
+ * @param out {@code non-null;} where to write
+ * @param amt {@code >= 0;} the number of spaces to write
+ */
+ private static void writeSpaces(Writer out, int amt) throws IOException {
+ while (amt > 0) {
+ out.write(' ');
+ amt--;
+ }
+ }
+}
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