Encode special characters and do formatting for HTML output
/*
* Helma License Notice
*
* The contents of this file are subject to the Helma License
* Version 2.0 (the "License"). You may not use this file except in
* compliance with the License. A copy of the License is available at
* http://adele.helma.org/download/helma/license.txt
*
* http://adele.helma.org/download/helma/license.txt:
*
Copyright (c) 1999-2002 Helma Project. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. 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.
3. Products derived from this software may not be called "Helma"
or "Hop", nor may "Helma" or "Hop" appear in their name, without
prior written permission of the Helma Project Group. For written
permission, please contact helma@helma.org.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 HELMA PROJECT OR ITS
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.
*/
import java.util.*;
/**
* This is a utility class to encode special characters and do formatting
* for HTML output.
* @author Hannes Wallnoefer
*/
public final class HtmlEncoder {
// transformation table for characters 128 to 255. These actually fall into two
// groups, put together for efficiency: "Windows" chacacters 128-159 such as
// "smart quotes", which are encoded to valid Unicode entities, and
// valid ISO-8859 caracters 160-255, which are encoded to the symbolic HTML
// entity. Everything >= 256 is encoded to a numeric entity.
//
// for mor on HTML entities see http://www.pemberley.com/janeinfo/latin1.html and
// ftp://ftp.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT
//
static final String[] transform = {
"€", // 128
"", // empty string means character is undefined in unicode
"‚",
"ƒ",
"„",
"…",
"†",
"‡",
"ˆ",
"‰",
"Š",
"‹",
"Œ",
"",
"Ž",
"",
"",
"‘",
"’",
"“",
"”",
"•",
"–",
"—",
"˜",
"™",
"š",
"›",
"œ",
"",
"ž",
"Ÿ", // 159
" ", // 160
"¡",
"¢",
"£",
"¤",
"¥",
"¦",
"§",
"¨",
"©",
"ª",
"«",
"¬",
"­",
"®",
"¯",
"°",
"±",
"²",
"³",
"´",
"µ",
"¶",
"·",
"¸",
"¹",
"º",
"»",
"¼",
"½",
"¾",
"¿",
"À",
"Á",
"Â",
"Ã",
"Ä",
"Å",
"Æ",
"Ç",
"È",
"É",
"Ê",
"Ë",
"Ì",
"Í",
"Î",
"Ï",
"Ð",
"Ñ",
"Ò",
"Ó",
"Ô",
"Õ",
"Ö",
"×",
"Ø",
"Ù",
"Ú",
"Û",
"Ü",
"Ý",
"Þ",
"ß",
"à",
"á",
"â",
"ã",
"ä",
"å",
"æ",
"ç",
"è",
"é",
"ê",
"ë",
"ì",
"í",
"î",
"ï",
"ð",
"ñ",
"ò",
"ó",
"ô",
"õ",
"ö",
"÷",
"ø",
"ù",
"ú",
"û",
"ü",
"ý",
"þ",
"ÿ" // 255
};
static final HashSet allTags = new HashSet();
static {
allTags.add("a");
allTags.add("abbr");
allTags.add("acronym");
allTags.add("address");
allTags.add("applet");
allTags.add("area");
allTags.add("b");
allTags.add("base");
allTags.add("basefont");
allTags.add("bdo");
allTags.add("bgsound");
allTags.add("big");
allTags.add("blink");
allTags.add("blockquote");
allTags.add("bq");
allTags.add("body");
allTags.add("br");
allTags.add("button");
allTags.add("caption");
allTags.add("center");
allTags.add("cite");
allTags.add("code");
allTags.add("col");
allTags.add("colgroup");
allTags.add("del");
allTags.add("dfn");
allTags.add("dir");
allTags.add("div");
allTags.add("dl");
allTags.add("dt");
allTags.add("dd");
allTags.add("em");
allTags.add("embed");
allTags.add("fieldset");
allTags.add("font");
allTags.add("form");
allTags.add("frame");
allTags.add("frameset");
allTags.add("h1");
allTags.add("h2");
allTags.add("h3");
allTags.add("h4");
allTags.add("h5");
allTags.add("h6");
allTags.add("head");
allTags.add("html");
allTags.add("hr");
allTags.add("i");
allTags.add("iframe");
allTags.add("img");
allTags.add("input");
allTags.add("ins");
allTags.add("isindex");
allTags.add("kbd");
allTags.add("label");
allTags.add("legend");
allTags.add("li");
allTags.add("link");
allTags.add("listing");
allTags.add("map");
allTags.add("marquee");
allTags.add("menu");
allTags.add("meta");
allTags.add("nobr");
allTags.add("noframes");
allTags.add("noscript");
allTags.add("object");
allTags.add("ol");
allTags.add("option");
allTags.add("optgroup");
allTags.add("p");
allTags.add("param");
allTags.add("plaintext");
allTags.add("pre");
allTags.add("q");
allTags.add("s");
allTags.add("samp");
allTags.add("script");
allTags.add("select");
allTags.add("small");
allTags.add("span");
allTags.add("strike");
allTags.add("strong");
allTags.add("style");
allTags.add("sub");
allTags.add("sup");
allTags.add("table");
allTags.add("tbody");
allTags.add("td");
allTags.add("textarea");
allTags.add("tfoot");
allTags.add("th");
allTags.add("thead");
allTags.add("title");
allTags.add("tr");
allTags.add("tt");
allTags.add("u");
allTags.add("ul");
allTags.add("var");
allTags.add("wbr");
allTags.add("xmp");
}
// HTML block tags need to suppress automatic newline to <br>
// conversion around them to look good. However, they differ
// in how many newlines around them should ignored. These sets
// help to treat each tag right in newline conversion.
static final HashSet internalTags = new HashSet();
static final HashSet blockTags = new HashSet();
static final HashSet semiBlockTags = new HashSet();
static {
// actual block level elements
semiBlockTags.add("address");
semiBlockTags.add("dir");
semiBlockTags.add("div");
semiBlockTags.add("table");
blockTags.add("blockquote");
blockTags.add("center");
blockTags.add("dl");
blockTags.add("fieldset");
blockTags.add("form");
blockTags.add("h1");
blockTags.add("h2");
blockTags.add("h3");
blockTags.add("h4");
blockTags.add("h5");
blockTags.add("h6");
blockTags.add("hr");
blockTags.add("isindex");
blockTags.add("ol");
blockTags.add("p");
blockTags.add("pre");
blockTags.add("ul");
internalTags.add("menu");
internalTags.add("noframes");
internalTags.add("noscript");
/// to be treated as block level elements
semiBlockTags.add("th");
blockTags.add("br");
blockTags.add("dd");
blockTags.add("dt");
blockTags.add("frameset");
blockTags.add("li");
blockTags.add("td");
internalTags.add("tbody");
internalTags.add("tfoot");
internalTags.add("thead");
internalTags.add("tr");
}
// set of tags that are always empty
static final HashSet emptyTags = new HashSet();
static {
emptyTags.add("area");
emptyTags.add("base");
emptyTags.add("basefont");
emptyTags.add("br");
emptyTags.add("col");
emptyTags.add("frame");
emptyTags.add("hr");
emptyTags.add("img");
emptyTags.add("input");
emptyTags.add("isindex");
emptyTags.add("link");
emptyTags.add("meta");
emptyTags.add("param");
}
static final byte TAG_NAME = 0;
static final byte TAG_SPACE = 1;
static final byte TAG_ATT_NAME = 2;
static final byte TAG_ATT_VAL = 3;
static final byte TEXT = 0;
static final byte SEMIBLOCK = 1;
static final byte BLOCK = 2;
static final byte INTERNAL = 3;
static final String newLine = System.getProperty("line.separator");
/**
* Do "smart" encodging on a string. This means that valid HTML entities and tags,
* Helma macros and HTML comments are passed through unescaped, while
* other occurrences of '<', '>' and '&' are encoded to HTML entities.
*/
public final static String encode(String str) {
if (str == null) {
return null;
}
int l = str.length();
if (l == 0) {
return "";
}
// try to make stringbuffer large enough from the start
StringBuffer ret = new StringBuffer(Math.round(l * 1.4f));
encode(str, ret, false, null);
return ret.toString();
}
/**
* Do "smart" encodging on a string. This means that valid HTML entities and tags,
* Helma macros and HTML comments are passed through unescaped, while
* other occurrences of '<', '>' and '&' are encoded to HTML entities.
*/
public final static void encode(String str, StringBuffer ret) {
encode(str, ret, false, null);
}
/**
* Do "smart" encodging on a string. This means that valid HTML entities and tags,
* Helma macros and HTML comments are passed through unescaped, while
* other occurrences of '<', '>' and '&' are encoded to HTML entities.
*
* @param str the string to encode
* @param ret the string buffer to encode to
* @param paragraphs if true use p tags for paragraphs, otherwise just use br's
* @param allowedTags a set containing the names of allowed tags as strings. All other
* tags will be escaped
*/
public final static void encode(String str, StringBuffer ret,
boolean paragraphs, Set allowedTags) {
if (str == null) {
return;
}
int l = str.length();
// where to insert the <p> tag in case we want to create a paragraph later on
int paragraphStart = ret.length();
// what kind of element/text are we leaving and entering?
// this is one of TEXT|SEMIBLOCK|BLOCK|INTERNAL
// depending on this information, we decide whether and how to insert
// paragraphs and line breaks. "entering" a tag means we're at the '<'
// and exiting means we're at the '>', not that it's a start or close tag.
byte entering = TEXT;
byte exiting = TEXT;
Stack openTags = new Stack();
// are we currently within a < and a > that consitute some kind of tag?
// we use tag balancing to know whether we are inside a tag (and should
// pass things through unchanged) or outside (and should encode stuff).
boolean insideTag = false;
// are we inside an HTML tag?
boolean insideHtmlTag = false;
boolean insideCloseTag = false;
byte htmlTagMode = TAG_NAME;
// if we are inside a <code> tag, we encode everything to make
// documentation work easier
boolean insideCodeTag = false;
boolean insidePreTag = false;
// are we within a Helma <% macro %> tag? We treat macro tags and
// comments specially, since we can't rely on tag balancing
// to know when we leave a macro tag or comment.
boolean insideMacroTag = false;
// are we inside an HTML comment?
boolean insideComment = false;
// the quotation mark we are in within an HTML or Macro tag, if any
char htmlQuoteChar = '\u0000';
char macroQuoteChar = '\u0000';
// number of newlines met since the last non-whitespace character
int linebreaks = 0;
// did we meet a backslash escape?
boolean escape = false;
boolean triggerBreak = false;
for (int i = 0; i < l; i++) {
char c = str.charAt(i);
// step one: check if this is the beginning of an HTML tag, comment or
// Helma macro.
if (c == '<') {
if (i < (l - 2)) {
if (!insideMacroTag && ('%' == str.charAt(i + 1))) {
// this is the beginning of a Helma macro tag
if (!insideCodeTag) {
insideMacroTag = insideTag = true;
macroQuoteChar = '\u0000';
}
} else if (('!' == str.charAt(i + 1)) && ('-' == str.charAt(i + 2))) {
// the beginning of an HTML comment?
if (!insideCodeTag) {
insideComment = insideTag = ((i < (l - 3)) &&
('-' == str.charAt(i + 3)));
}
} else if (!insideTag) {
// check if this is a HTML tag.
insideCloseTag = ('/' == str.charAt(i + 1));
int tagStart = insideCloseTag ? (i + 2) : (i + 1);
int j = tagStart;
while ((j < l) && Character.isLetterOrDigit(str.charAt(j)))
j++;
if ((j > tagStart) && (j < l)) {
String tagName = str.substring(tagStart, j).toLowerCase();
if ("code".equals(tagName) && insideCloseTag &&
insideCodeTag) {
insideCodeTag = false;
}
if (((allowedTags == null) || allowedTags.contains(tagName)) &&
allTags.contains(tagName) && !insideCodeTag) {
insideHtmlTag = insideTag = true;
htmlQuoteChar = '\u0000';
htmlTagMode = TAG_NAME;
exiting = entering;
entering = TEXT;
if (internalTags.contains(tagName)) {
entering = INTERNAL;
} else if (blockTags.contains(tagName)) {
entering = BLOCK;
} else if (semiBlockTags.contains(tagName)) {
entering = paragraphs ? BLOCK : SEMIBLOCK;
}
if (entering > 0) {
triggerBreak = !insidePreTag;
}
if (insideCloseTag) {
int t = openTags.search(tagName);
if (t == -1) {
i = j;
insideHtmlTag = insideTag = false;
continue;
} else if (t > 1) {
for (int k = 1; k < t; k++) {
Object tag = openTags.pop();
if (!emptyTags.contains(tag)) {
ret.append("</");
ret.append(tag);
ret.append(">");
}
}
}
openTags.pop();
} else {
openTags.push(tagName);
}
if ("code".equals(tagName) && !insideCloseTag) {
insideCodeTag = true;
}
if ("pre".equals(tagName)) {
insidePreTag = !insideCloseTag;
}
}
}
}
} // if (i < l-2)
}
if ((triggerBreak || linebreaks > 0) && !Character.isWhitespace(c)) {
if (!insideTag) {
exiting = entering;
entering = TEXT;
if (exiting >= SEMIBLOCK) {
paragraphStart = ret.length();
}
}
if (entering != INTERNAL && exiting != INTERNAL) {
int swallowBreaks = 0;
if (paragraphs &&
(entering != BLOCK || exiting != BLOCK) &&
(exiting < BLOCK) &&
(linebreaks > 1) &&
paragraphStart < ret.length()) {
ret.insert(paragraphStart, "<p>");
ret.append("</p>");
swallowBreaks = 2;
}
// treat entering a SEMIBLOCK as entering a TEXT
int _entering = entering == SEMIBLOCK ? TEXT : entering;
for (int k = linebreaks-1; k>=0; k--) {
if (k >= swallowBreaks && k >= _entering && k >= exiting) {
ret.append("<br />");
}
ret.append(newLine);
}
if (exiting >= SEMIBLOCK || linebreaks > 1) {
paragraphStart = ret.length();
}
}
linebreaks = 0;
triggerBreak = false;
}
switch (c) {
case '<':
if (insideTag) {
ret.append('<');
} else {
ret.append("<");
}
break;
case '&':
// check if this is an HTML entity already,
// in which case we pass it though unchanged
if ((i < (l - 3)) && !insideCodeTag) {
// is this a numeric entity?
if (str.charAt(i + 1) == '#') {
int j = i + 2;
while ((j < l) && Character.isDigit(str.charAt(j)))
j++;
if ((j < l) && (str.charAt(j) == ';')) {
ret.append("&");
break;
}
} else {
int j = i + 1;
while ((j < l) && Character.isLetterOrDigit(str.charAt(j)))
j++;
if ((j < l) && (str.charAt(j) == ';')) {
ret.append("&");
break;
}
}
}
// we didn't reach a break, so encode the ampersand as HTML entity
ret.append("&");
break;
case '\\':
ret.append(c);
if (insideTag && !insideComment) {
escape = !escape;
}
break;
case '"':
case '\'':
ret.append(c);
if (!insideComment) {
// check if the quote is escaped
if (insideMacroTag) {
if (escape) {
escape = false;
} else if (macroQuoteChar == c) {
macroQuoteChar = '\u0000';
} else if (macroQuoteChar == '\u0000') {
macroQuoteChar = c;
}
} else if (insideHtmlTag) {
if (escape) {
escape = false;
} else if (htmlQuoteChar == c) {
htmlQuoteChar = '\u0000';
htmlTagMode = TAG_SPACE;
} else if (htmlQuoteChar == '\u0000') {
htmlQuoteChar = c;
}
}
}
break;
case '\n':
if (insideTag || insidePreTag) {
ret.append('\n');
} else {
linebreaks++;
}
break;
case '\r':
if (insideTag || insidePreTag) {
ret.append('\r');
}
break;
case '>':
// For Helma macro tags and comments, we overrule tag balancing,
// i.e. we don't require that '<' and '>' be balanced within
// macros and comments. Rather, we check for the matching closing tag.
if (insideComment) {
ret.append('>');
insideComment = !((str.charAt(i - 2) == '-') &&
(str.charAt(i - 1) == '-'));
} else if (insideMacroTag) {
ret.append('>');
insideMacroTag = !((str.charAt(i - 1) == '%') &&
(macroQuoteChar == '\u0000'));
} else if (insideHtmlTag) {
ret.append('>');
// only leave HTML tag if quotation marks are balanced
// within that tag.
insideHtmlTag = htmlQuoteChar != '\u0000';
// Check if this is an empty tag so we don't generate an
// additional </close> tag.
if (str.charAt(i - 1) == '/') {
// this is to avoid misinterpreting tags like
// <a href=http://foo/> as empty
if (htmlTagMode != TAG_ATT_VAL && htmlTagMode != TAG_ATT_NAME) {
openTags.pop();
}
}
exiting = entering;
if (exiting > 0) {
triggerBreak = !insidePreTag;
}
} else {
ret.append(">");
}
// check if we still are inside any kind of tag
insideTag = insideComment || insideMacroTag || insideHtmlTag;
insideCloseTag = insideTag;
break;
default:
if (insideHtmlTag && !insideCloseTag) {
switch(htmlTagMode) {
case TAG_NAME:
if (!Character.isLetterOrDigit(c)) {
htmlTagMode = TAG_SPACE;
}
break;
case TAG_SPACE:
if (Character.isLetterOrDigit(c)) {
htmlTagMode = TAG_ATT_NAME;
}
break;
case TAG_ATT_NAME:
if (c == '=') {
htmlTagMode = TAG_ATT_VAL;
} else if (c == ' ') {
htmlTagMode = TAG_SPACE;
}
break;
case TAG_ATT_VAL:
if (Character.isWhitespace(c) && htmlQuoteChar == '\u0000') {
htmlTagMode = TAG_SPACE;
}
break;
}
}
if (c < 128) {
ret.append(c);
} else if ((c >= 128) && (c < 256)) {
ret.append(transform[c - 128]);
} else {
ret.append("&#");
ret.append((int) c);
ret.append(";");
}
escape = false;
}
}
// if tags were opened but not closed, close them.
int o = openTags.size();
if (o > 0) {
for (int k = 0; k < o; k++) {
Object tag = openTags.pop();
if (!emptyTags.contains(tag)) {
ret.append("</");
ret.append(tag);
ret.append(">");
}
}
}
// add remaining newlines we may have collected
int swallowBreaks = 0;
if (paragraphs && entering < BLOCK) {
ret.insert(paragraphStart, "<p>");
ret.append("</p>");
swallowBreaks = 2;
}
if (linebreaks > 0) {
for (int i = linebreaks-1; i>=0; i--) {
if (i >= swallowBreaks && i > exiting) {
ret.append("<br />");
}
ret.append(newLine);
}
}
}
/**
*
*/
public final static String encodeFormValue(String str) {
if (str == null) {
return null;
}
int l = str.length();
if (l == 0) {
return "";
}
StringBuffer ret = new StringBuffer(Math.round(l * 1.2f));
encodeAll(str, ret, false);
return ret.toString();
}
/**
*
*/
public final static void encodeFormValue(String str, StringBuffer ret) {
encodeAll(str, ret, false);
}
/**
*
*/
public final static String encodeAll(String str) {
if (str == null) {
return null;
}
int l = str.length();
if (l == 0) {
return "";
}
StringBuffer ret = new StringBuffer(Math.round(l * 1.2f));
encodeAll(str, ret, true);
return ret.toString();
}
/**
*
*/
public final static void encodeAll(String str, StringBuffer ret) {
encodeAll(str, ret, true);
}
/**
*
*/
public final static void encodeAll(String str, StringBuffer ret, boolean encodeNewline) {
if (str == null) {
return;
}
int l = str.length();
for (int i = 0; i < l; i++) {
char c = str.charAt(i);
switch (c) {
case '<':
ret.append("<");
break;
case '>':
ret.append(">");
break;
case '&':
ret.append("&");
break;
case '"':
ret.append(""");
break;
case '\n':
if (encodeNewline) {
ret.append("<br />");
}
ret.append('\n');
break;
default:
// ret.append (c);
if (c < 128) {
ret.append(c);
} else if ((c >= 128) && (c < 256)) {
ret.append(transform[c - 128]);
} else {
ret.append("&#");
ret.append((int) c);
ret.append(";");
}
}
}
}
/**
*
*
* @param str ...
*
* @return ...
*/
public final static String encodeXml(String str) {
if (str == null) {
return null;
}
int l = str.length();
if (l == 0) {
return "";
}
StringBuffer ret = new StringBuffer(Math.round(l * 1.2f));
encodeXml(str, ret);
return ret.toString();
}
/**
*
*
* @param str ...
* @param ret ...
*/
public final static void encodeXml(String str, StringBuffer ret) {
if (str == null) {
return;
}
int l = str.length();
for (int i = 0; i < l; i++) {
char c = str.charAt(i);
switch (c) {
case '<':
ret.append("<");
break;
case '>':
ret.append(">");
break;
case '&':
ret.append("&");
break;
case '"':
ret.append(""");
break;
case '\'':
ret.append("'");
break;
default:
if (c < 0x20) {
// sort out invalid XML characters below 0x20 - all but 0x9, 0xA and 0xD.
// The trick is an adaption of java.lang.Character.isSpace().
if (((((1L << 0x9) | (1L << 0xA) | (1L << 0xD)) >> c) & 1L) != 0) {
ret.append(c);
}
} else {
ret.append(c);
}
}
}
}
// test method
public static String printCharRange(int from, int to) {
StringBuffer response = new StringBuffer();
for (int i = from; i < to; i++) {
response.append(i);
response.append(" ");
response.append((char) i);
response.append(" ");
if (i < 128) {
response.append((char) i);
} else if ((i >= 128) && (i < 256)) {
response.append(transform[i - 128]);
} else {
response.append("&#");
response.append(i);
response.append(";");
}
response.append("\r\n");
}
return response.toString();
}
// for testing...
public static void main(String[] args) {
for (int i = 0; i < args.length; i++)
System.err.println(encode(args[i]));
}
}
// end of class
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