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Diffstat (limited to 'gnu/javax/swing/text/html/css/CSSScanner.java')
| -rw-r--r-- | gnu/javax/swing/text/html/css/CSSScanner.java | 717 |
1 files changed, 717 insertions, 0 deletions
diff --git a/gnu/javax/swing/text/html/css/CSSScanner.java b/gnu/javax/swing/text/html/css/CSSScanner.java new file mode 100644 index 000000000..a402b9522 --- /dev/null +++ b/gnu/javax/swing/text/html/css/CSSScanner.java @@ -0,0 +1,717 @@ +/* CSSScanner.java -- A parser for CSS stylesheets + Copyright (C) 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.javax.swing.text.html.css; + +import java.io.BufferedInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.Reader; + +/** + * A tokenizer for CSS stylesheets. This is based on the scanner definition + * from: + * + * http://www.w3.org/TR/CSS21/syndata.html#tokenization + * + * @author Roman Kennke (kennke@aicas.com) + */ +// TODO: Maybe implement more restrictive scanner: +// http://www.w3.org/TR/CSS21/grammar.html#q2 +class CSSScanner +{ + + // The tokens. This list is taken from: + // http://www.w3.org/TR/CSS21/syndata.html#tokenization + static final int IDENT = 1; + static final int ATKEYWORD = 2; + static final int STRING = 3; + static final int INVALID = 4; + static final int HASH = 5; + static final int NUMBER = 6; + static final int PERCENTAGE = 7; + static final int DIMENSION = 8; + static final int URI = 9; + static final int UNICODE_RANGE = 10; + static final int CDO = 11; + static final int CDC = 12; + static final int SEMICOLON = 13; + static final int CURLY_LEFT = 14; + static final int CURLY_RIGHT = 15; + static final int PAREN_LEFT = 16; + static final int PAREN_RIGHT = 17; + static final int BRACE_LEFT = 16; + static final int BRACE_RIGHT = 17; + static final int S = 18; + static final int COMMENT = 19; + static final int FUNCTION = 20; + static final int INCLUDES = 21; + static final int DASHMATCH = 22; + static final int DELIM = 23; + + // Additional tokens defined for convenience. + static final int EOF = -1; + + /** + * The input source. + */ + private Reader in; + + /** + * The parse buffer. + */ + char[] parseBuffer; + + /** + * The end index in the parseBuffer of the current token. + */ + int tokenEnd; + + /** + * The lookahead 'buffer'. + */ + private int[] lookahead; + + CSSScanner(Reader r) + { + lookahead = new int[2]; + lookahead[0] = -1; + lookahead[1] = -1; + parseBuffer = new char[2048]; + in = r; + } + + /** + * Fetches the next token. The actual character data is in the parseBuffer + * afterwards with the tokenStart at index 0 and the tokenEnd field + * pointing to the end of the token. + * + * @return the next token + */ + int nextToken() + throws IOException + { + tokenEnd = 0; + int token = -1; + int next = read(); + if (next != -1) + { + switch (next) + { + case ';': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = SEMICOLON; + break; + case '{': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = CURLY_LEFT; + break; + case '}': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = CURLY_RIGHT; + break; + case '(': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = PAREN_LEFT; + break; + case ')': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = PAREN_RIGHT; + break; + case '[': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = BRACE_LEFT; + break; + case ']': + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = BRACE_RIGHT; + break; + case '@': + parseBuffer[0] = (char) next; + tokenEnd = 1; + readIdent(); + token = ATKEYWORD; + break; + case '#': + parseBuffer[0] = (char) next; + tokenEnd = 1; + readName(); + token = HASH; + break; + case '\'': + case '"': + lookahead[0] = next; + readString(); + token = STRING; + break; + case ' ': + case '\t': + case '\r': + case '\n': + case '\f': + lookahead[0] = next; + readWhitespace(); + token = S; + break; + // FIXME: Detecting an URI involves several characters lookahead. +// case 'u': +// lookahead[0] = ch; +// readURI(); +// token = URI; +// break; + case '<': + parseBuffer[0] = (char) next; + parseBuffer[1] = (char) read(); + parseBuffer[2] = (char) read(); + parseBuffer[3] = (char) read(); + if (parseBuffer[1] == '!' && parseBuffer[2] == '-' + && parseBuffer[3] == '-') + { + token = CDO; + tokenEnd = 4; + } + else + throw new CSSLexicalException("expected CDO token"); + break; + case '/': + lookahead[0] = next; + readComment(); + token = COMMENT; + break; + case '~': + parseBuffer[0] = (char) next; + parseBuffer[1] = (char) read(); + if (parseBuffer[1] == '=') + token = INCLUDES; + else + throw new CSSLexicalException("expected INCLUDES token"); + break; + case '|': + parseBuffer[0] = (char) next; + parseBuffer[1] = (char) read(); + if (parseBuffer[1] == '=') + token = DASHMATCH; + else + throw new CSSLexicalException("expected DASHMATCH token"); + break; + case '-': + int ch2 = read(); + if (ch2 == '-') + { + int ch3 = read(); + if (ch3 == '>') + { + parseBuffer[0] = (char) next; + parseBuffer[1] = (char) ch2; + parseBuffer[2] = (char) ch3; + tokenEnd = 3; + token = CDC; + } + else + throw new CSSLexicalException("expected CDC token"); + } + else + { + lookahead[0] = next; + lookahead[1] = ch2; + readIdent(); + int ch3 = read(); + if (ch3 == -1 || ch3 != '(') + { + lookahead[0] = ch3; + token = IDENT; + } + else + { + parseBuffer[tokenEnd] = (char) ch3; + tokenEnd++; + token = FUNCTION; + } + } + break; + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + case '8': + case '9': + lookahead[0] = next; + readNum(); + int ch3 = read(); + if (ch3 == '%') + { + parseBuffer[tokenEnd] = (char) ch3; + tokenEnd++; + token = PERCENTAGE; + } + else if (ch3 == -1 || (! (ch3 == '_' + || (ch3 >= 'a' && ch3 <= 'z') + || (ch3 >= 'A' && ch3 <= 'Z') + || ch3 == '\\' || ch3 > 177))) + { + lookahead[0] = ch3; + token = NUMBER; + } + else + { + lookahead[0] = ch3; + readIdent(); + token = DIMENSION; + } + break; + default: + // Handle IDENT that don't begin with '-'. + if (next == '_' || (next >= 'a' && next <= 'z') + || (next >= 'A' && next <= 'Z') || next == '\\' || next > 177) + { + lookahead[0] = next; + readIdent(); + int ch4 = read(); + if (ch4 == -1 || ch4 != '(') + { + lookahead[0] = ch4; + token = IDENT; + } + else + { + parseBuffer[tokenEnd] = (char) ch4; + tokenEnd++; + token = FUNCTION; + } + } + else + { + parseBuffer[0] = (char) next; + tokenEnd = 1; + token = DELIM; + } + break; + } + } + return token; + } + + String currentTokenString() + { + return new String(parseBuffer, 0, tokenEnd); + } + + /** + * Reads one character from the input stream or from the lookahead + * buffer, if it contains one character. + * + * @return the next character + * + * @throws IOException if problems occur on the input source + */ + private int read() + throws IOException + { + int ret; + if (lookahead[0] != -1) + { + ret = lookahead[0]; + lookahead[0] = -1; + } + else if (lookahead[1] != -1) + { + ret = lookahead[1]; + lookahead[1] = -1; + } + else + { + ret = in.read(); + } + return ret; + } + + /** + * Reads and identifier. + * + * @throws IOException if something goes wrong in the input source or if + * the lexical analyser fails to read an identifier + */ + private void readIdent() + throws IOException + { + int ch1 = read(); + // Read possibly leading '-'. + if (ch1 == '-') + { + parseBuffer[tokenEnd] = (char) ch1; + tokenEnd++; + ch1 = read(); + } + // What follows must be '_' or a-z or A-Z or nonascii (>177) or an + // escape. + if (ch1 == '_' || (ch1 >= 'a' && ch1 <= 'z') + || (ch1 >= 'A' && ch1 <= 'Z') || ch1 > 177) + { + parseBuffer[tokenEnd] = (char) ch1; + tokenEnd++; + } + else if (ch1 == '\\') + { + // Try to read an escape. + lookahead[0] = ch1; + readEscape(); + } + else + throw new CSSLexicalException("First character of identifier incorrect"); + + // Read any number of [_a-zA-Z0-9-] chars. + int ch = read(); + while (ch != -1 && (ch == '_' || ch == '-' || (ch >= 'a' && ch <= 'z') + || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9'))) + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + } + + // Push back last read character since it doesn't belong to the IDENT. + lookahead[0] = ch; + } + + /** + * Reads an escape. + * + * @throws IOException if something goes wrong in the input source or if + * the lexical analyser fails to read an escape + */ + private void readEscape() + throws IOException + { + int ch = read(); + if (ch != -1 && ch == '\\') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + if ((ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f')) + { + // Read unicode escape. + // Zero to five 0-9a-f chars can follow. + int hexcount = 0; + ch = read(); + while (((ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f')) + && hexcount < 5) + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + hexcount++; + ch = read(); + } + // Now we can have a \r\n or any whitespace character following. + if (ch == '\r') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + if (ch == '\n') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + else + { + lookahead[0] = ch; + } + } + else if (ch == ' ' || ch == '\n' || ch == '\f' || ch == '\t') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + else + { + lookahead[0] = ch; + } + } + else if (ch != '\n' && ch != '\r' && ch != '\f') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + else + throw new CSSLexicalException("Can't read escape"); + } + else + throw new CSSLexicalException("Escape must start with '\\'"); + + } + + private void readName() + throws IOException + { + // Read first name character. + int ch = read(); + if (ch != -1 && (ch == '_' || ch == '-' || (ch >= 'a' && ch <= 'z') + || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9'))) + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + else + throw new CSSLexicalException("Invalid name"); + + // Read any number (at least one) of [_a-zA-Z0-9-] chars. + ch = read(); + while (ch != -1 && (ch == '_' || ch == '-' || (ch >= 'a' && ch <= 'z') + || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9'))) + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + + // Push back last read character since it doesn't belong to the IDENT. + lookahead[0] = ch; + } + + /** + * Reads in a string. + * + * @throws IOException + */ + private void readString() + throws IOException + { + int ch1 = read(); + if (ch1 != -1 && (ch1 == '\'' || ch1 == '\"')) + { + parseBuffer[tokenEnd] = (char) ch1; + tokenEnd++; + + // Read any number of chars until we hit another chc1 char. + // Reject newlines, except if prefixed with \. + int ch = read(); + while (ch != -1 && ch != ch1) + { + // Every non-newline and non-\ char should be ok. + if (ch != '\n' && ch != '\r' && ch != '\f' && ch != '\\') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + // Ok when followed by newline or as part of escape. + else if (ch == '\\') + { + int ch2 = read(); + if (ch2 == '\n' || ch2 == '\r') + { + parseBuffer[tokenEnd] = (char) ch; + parseBuffer[tokenEnd + 1] = (char) ch2; + tokenEnd += 2; + } + else + { + // Try to parse an escape. + lookahead[0] = ch; + lookahead[1] = ch2; + readEscape(); + } + } + else + throw new CSSLexicalException("Invalid string"); + + ch = read(); + } + if (ch != -1) + { + // Push the final char on the buffer. + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + } + else + throw new CSSLexicalException("Unterminated string"); + } + else + throw new CSSLexicalException("Invalid string"); + } + + /** + * Reads a chunk of whitespace. + * + * @throws IOException + */ + private void readWhitespace() + throws IOException + { + int ch = read(); + while (ch != -1 && (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' + || ch == '\f')) + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + } + // Push back last character read. + lookahead[0] = ch; + + } + + private void readURI() + throws IOException + { + // FIXME: Implement. + } + + /** + * Reads a comment block. + * + * @throws IOException + */ + private void readComment() + throws IOException + { + // First we need a / and a * + int ch = read(); + if (ch != -1 && ch == '/') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + if (ch != -1 && ch == '*') + { + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + boolean finished = false; + int lastChar = ch; + ch = read(); + while (! finished && ch != -1) + { + if (lastChar == '*' && ch == '/') + finished = true; + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + lastChar = ch; + ch = read(); + } + } + } + if (ch == -1) + throw new CSSLexicalException("Unterminated comment"); + + // Push back last character read. + lookahead[0] = ch; + } + + /** + * Reads a number. + * + * @throws IOException + */ + private void readNum() + throws IOException + { + boolean hadDot = false; + // First char must be number or . + int ch = read(); + if (ch != -1 && ((ch >= '0' && ch <= '9') || ch == '.')) + { + if (ch == '.') + hadDot = true; + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + // Now read in any number of digits afterwards, and maybe one dot, + // if we hadn't one already. + ch = read(); + while (ch != -1 && ((ch >= '0' && ch <= '9') + || (ch == '.' && ! hadDot))) + { + if (ch == '.') + hadDot = true; + parseBuffer[tokenEnd] = (char) ch; + tokenEnd++; + ch = read(); + } + } + else + throw new CSSLexicalException("Invalid number"); + + // Check if we haven't accidentally finished with a dot. + if (parseBuffer[tokenEnd - 1] == '.') + throw new CSSLexicalException("Invalid number"); + + // Push back last character read. + lookahead[0] = ch; + } + + /** + * For testing, we read in the default.css in javax/swing/text/html + * + * @param args + */ + public static void main(String[] args) + { + try + { + String name = "/javax/swing/text/html/default.css"; + InputStream in = CSSScanner.class.getResourceAsStream(name); + BufferedInputStream bin = new BufferedInputStream(in); + InputStreamReader r = new InputStreamReader(bin); + CSSScanner s = new CSSScanner(r); + int token; + do + { + token = s.nextToken(); + System.out.println("token: " + token + ": " + + s.currentTokenString()); + } while (token != -1); + } + catch (IOException ex) + { + ex.printStackTrace(); + } + } +} |