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// Copyright (c) 2012 Jeff Ichnowski
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// * Redistributions of source code must retain the above
// copyright notice, this list of conditions and the following
// disclaimer.
//
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials
// provided with the distribution.
//
// * Neither the name of the OWASP nor the names of its
// contributors may be used to endorse or promote products
// derived from this software without specific prior written
// permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
package org.owasp.encoder;
import java.nio.CharBuffer;
import java.nio.charset.CoderResult;
/**
*
* HTMLEncoder -- an encoder for HTML contexts. Currently most HTML-based
* contexts are properly handled by {@link XMLEncoder}. The remaining
* HTML-specific context of "unquoted attributes" could not be added to the
* XMLEncoder without slowing it down. This class implements that remaining
* context: unquoted attribute values.
*
*
* Note: because this context is likely small strings, and hopefully rarely
* used, no effort was put into optimizing this encoder.
*
* @author Jeff Ichnowski
*/
class HTMLEncoder extends Encoder {
/**
* Number of characters in the encoding prefix and suffix when using decimal
* numeric encodings of the form "&#...;".
*/
private static final int ENCODE_AFFIX_CHAR_COUNT = 3;
/**
* Encoding for '\t'.
*/
private static final char[] TAB = " ".toCharArray();
/**
* Encoding for '&'.
*/
private static final char[] AMP = "&".toCharArray();
/**
* Encoding for '<'.
*/
private static final char[] LT = "<".toCharArray();
/**
* Encoding for '>'.
*/
private static final char[] GT = ">".toCharArray();
// The large table-switch implementation used here is fast to
// implement but slower at runtime than tuned-for-expected-input
// encoders that use selective if/else's. Look at the results of
// BenchmarkTest to see the difference. See note in javadoc as to
// reasoning.
// On Core i7 (Sandybridge)
// Baseline is 371.401009 ns/op
// Benchmarked Encode.forXml: 324.219992 ns/op (-12.70% on baseline)
// Benchmarked Encode.forHtmlUnquotedAttribute: 821.583263 ns/op (+121.21% on baseline)
@Override
int maxEncodedLength(int n) {
// if everything is line separators and paragraph separators then
// we get "⁛"
return n * (ENCODE_AFFIX_CHAR_COUNT + 4);
}
@Override
int firstEncodedOffset(String input, int off, int len) {
final int n = off + len;
for (int i = off; i < n; ++i) {
final char ch = input.charAt(i);
switch (ch) {
case '\t':
case '\r':
case '\f':
case '\n':
case ' ':
case Unicode.NEL:
case '\"':
case '\'':
case '/':
case '=':
case '`':
case '&':
case '<':
case '>':
return i;
case '!':
case '#':
case '$':
case '%':
case '(':
case ')':
case '*':
case '+':
case ',':
case '-':
case '.':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case ':':
case ';':
case '?':
case '@':
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
case 'G':
case 'H':
case 'I':
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case 'Q':
case 'R':
case 'S':
case 'T':
case 'U':
case 'V':
case 'W':
case 'X':
case 'Y':
case 'Z':
case '[':
case '\\':
case ']':
case '^':
case '_':
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
case 'g':
case 'h':
case 'i':
case 'j':
case 'k':
case 'l':
case 'm':
case 'n':
case 'o':
case 'p':
case 'q':
case 'r':
case 's':
case 't':
case 'u':
case 'v':
case 'w':
case 'x':
case 'y':
case 'z':
case '{':
case '|':
case '}':
case '~':
break; // valid
default:
if (Character.isHighSurrogate(ch)) {
if (i + 1 < n) {
if (Character.isLowSurrogate(input.charAt(i + 1))) {
int cp = Character.toCodePoint(ch, input.charAt(i + 1));
if (Unicode.isNonCharacter(cp)) {
return i;
} else {
++i;
}
break;
}
} else {
return i;
}
}
if (ch <= Unicode.MAX_C1_CTRL_CHAR
|| Character.MIN_SURROGATE <= ch && ch <= Character.MAX_SURROGATE
|| ch > '\ufffd'
|| ('\ufdd0' <= ch && ch <= '\ufdef')
|| ch == Unicode.LINE_SEPARATOR || ch == Unicode.PARAGRAPH_SEPARATOR)
{
return i;
}
}
}
return n;
}
/**
* Appends a source array verbatim to the output array. Caller must insure
* there is enough space in the array for the output.
*
* @param src the characters to copy
* @param out the output buffer
* @param j the offset where to write in the output buffer
* @return {@code j + src.length}
*/
static int append(char[] src, char[] out, int j) {
System.arraycopy(src, 0, out, j, src.length);
return j + src.length;
}
/**
* Appends the numerically encoded version of {@code codePoint} to the
* output buffer. Caller must insure there is enough space for the output.
*
* @param codePoint the character to encode
* @param out the output buffer
* @param j the offset where to write in the output buffer
* @return {@code j} + the encoded length.
*/
static int encode(int codePoint, char[] out, int j) {
out[j++] = '&';
out[j++] = '#';
if (codePoint >= 1000) {
out[j++] = (char) (codePoint / 1000 % 10 + '0');
}
if (codePoint >= 100) {
out[j++] = (char) (codePoint / 100 % 10 + '0');
}
if (codePoint >= 10) {
out[j++] = (char) (codePoint / 10 % 10 + '0');
}
out[j++] = (char) (codePoint % 10 + '0');
out[j++] = ';';
return j;
}
//CSOFF: MethodLength
@Override
CoderResult encodeArrays(CharBuffer input, CharBuffer output, boolean endOfInput) {
final char[] in = input.array();
final char[] out = output.array();
int i = input.arrayOffset() + input.position();
final int n = input.arrayOffset() + input.limit();
int j = output.arrayOffset() + output.position();
final int m = output.arrayOffset() + output.limit();
charLoop:
for (; i < n; ++i) {
final char ch = in[i];
// gigantic switch, hopefully compiled to a tableswitch.
// this approach appears to be slower than the if/else
// approach used in the other encoders. Perhaps an artifact
// of the CPU's branch predictor, or possible additional
// overhead of range checking, or having the entire table
// available to the cache. If time allows, it would
// interesting to find out.
switch (ch) {
case '\t':
if (j + TAB.length > m) {
return overflow(input, i, output, j);
}
j = append(TAB, out, j);
break;
case '\r':
case '\n':
case '\f':
case ' ':
case '\"':
case '\'':
case '/':
case '=':
case '`':
if (ENCODE_AFFIX_CHAR_COUNT + 2 + j > m) {
return overflow(input, i, output, j);
}
j = encode(ch, out, j);
break;
case Unicode.NEL:
if (ENCODE_AFFIX_CHAR_COUNT + 3 + j > m) {
return overflow(input, i, output, j);
}
j = encode(ch, out, j);
break;
case '&':
if (j + AMP.length > m) {
return overflow(input, i, output, j);
}
j = append(AMP, out, j);
break;
case '<':
if (j + LT.length > m) {
return overflow(input, i, output, j);
}
j = append(LT, out, j);
break;
case '>':
if (j + GT.length > m) {
return overflow(input, i, output, j);
}
j = append(GT, out, j);
break;
case '!':
case '#':
case '$':
case '%':
case '(':
case ')':
case '*':
case '+':
case ',':
case '-':
case '.':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case ':':
case ';':
case '?':
case '@':
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
case 'G':
case 'H':
case 'I':
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case 'Q':
case 'R':
case 'S':
case 'T':
case 'U':
case 'V':
case 'W':
case 'X':
case 'Y':
case 'Z':
case '[':
case '\\':
case ']':
case '^':
case '_':
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
case 'g':
case 'h':
case 'i':
case 'j':
case 'k':
case 'l':
case 'm':
case 'n':
case 'o':
case 'p':
case 'q':
case 'r':
case 's':
case 't':
case 'u':
case 'v':
case 'w':
case 'x':
case 'y':
case 'z':
case '{':
case '|':
case '}':
case '~':
if (j >= m) {
return overflow(input, i, output, j);
}
out[j++] = ch;
break;
default:
if (Character.isHighSurrogate(ch)) {
if (i + 1 < n) {
if (Character.isLowSurrogate(in[i + 1])) {
int cp = Character.toCodePoint(ch, in[i + 1]);
if (Unicode.isNonCharacter(cp)) {
if (j >= m) {
return overflow(input, i, output, j);
}
out[j++] = '-';
++i;
} else {
if (j + 1 >= m) {
return overflow(input, i, output, j);
}
out[j++] = ch;
out[j++] = in[++i];
}
break;
}
} else if (!endOfInput) {
break charLoop;
}
}
if (j >= m) {
return overflow(input, i, output, j);
}
if (ch <= Unicode.MAX_C1_CTRL_CHAR
|| Character.MIN_SURROGATE <= ch && ch <= Character.MAX_SURROGATE
|| ch > '\ufffd'
|| ('\ufdd0' <= ch && ch <= '\ufdef'))
{
// invalid
out[j++] = '-';
} else if (ch == Unicode.LINE_SEPARATOR || ch == Unicode.PARAGRAPH_SEPARATOR) {
if (ENCODE_AFFIX_CHAR_COUNT + 4 + j > m) {
return overflow(input, i, output, j);
}
j = encode(ch, out, j);
} else {
out[j++] = ch;
}
}
}
return underflow(input, i, output, j);
}
//CSON: MethodLength
}