-package be.nikiroo.utils.streams;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-/**
- * This {@link InputStream} will change some of its content by replacing it with
- * something else.
- *
- * @author niki
- */
-public class ReplaceInputStream extends BufferedInputStream {
- private byte[] from;
- private byte[] to;
-
- private byte[] source;
- private int spos;
- private int slen;
-
- /**
- * Create a {@link ReplaceInputStream} that will replace <tt>from</tt> with
- * <tt>to</tt>.
- *
- * @param in
- * the under-laying {@link InputStream}
- * @param from
- * the {@link String} to replace
- * @param to
- * the {@link String} to replace with
- */
- public ReplaceInputStream(InputStream in, String from, String to) {
- this(in, StreamUtils.bytes(from), StreamUtils.bytes(to));
- }
-
- /**
- * Create a {@link ReplaceInputStream} that will replace <tt>from</tt> with
- * <tt>to</tt>.
- *
- * @param in
- * the under-laying {@link InputStream}
- * @param from
- * the value to replace
- * @param to
- * the value to replace with
- */
- public ReplaceInputStream(InputStream in, byte[] from, byte[] to) {
- super(in);
- this.from = from;
- this.to = to;
-
- source = new byte[4096];
- spos = 0;
- slen = 0;
- }
-
- @Override
- protected int read(InputStream in, byte[] buffer) throws IOException {
- if (buffer.length < to.length || source.length < to.length * 2) {
- throw new IOException(
- "An underlaying buffer is too small for this replace value");
- }
-
- if (spos >= slen) {
- spos = 0;
- slen = in.read(source);
- }
-
- // Note: very simple, not efficient implementation, sorry.
- int count = 0;
- while (spos < slen && count < buffer.length - to.length) {
- if (from.length > 0
- && StreamUtils.startsWith(from, source, spos, slen)) {
- System.arraycopy(to, 0, buffer, spos, to.length);
- count += to.length;
- spos += from.length;
- } else {
- buffer[count++] = source[spos++];
- }
- }
-
- return count;
- }
-}