CSV.java

import java.util.*; import com.darwinsys.util.Debug; /** Parse comma-separated values (CSV), a common Windows file format. * Sample input: "LU",86.25,"11/4/1998","2:19PM",+4.0625 * <p> * Inner logic adapted from a C++ original that was * Copyright (C) 1999 Lucent Technologies * Excerpted from 'The Practice of Programming' * by Brian W. Kernighan and Rob Pike. * <p> * Included by permission of the http://tpop.awl.com/ web site, * which says: * "You may use this code for any purpose, as long as you leave * the copyright notice and book citation attached." I have done so. * @author Brian W. Kernighan and Rob Pike (C++ original) * @author Ian F. Darwin (translation into Java and removal of I/O) * @author Ben Ballard (rewrote advQuoted to handle '""' and for readability) */ public class CSV { public static final char DEFAULT_SEP = ','; /** Construct a CSV parser, with the default separator (','). */ public CSV( ) { this(DEFAULT_SEP); } /** Construct a CSV parser with a given separator. * @param sep The single char for the separator (not a list of * separator characters) */ public CSV(char sep) { fieldSep = sep; } /** The fields in the current String */ protected List list = new ArrayList( ); /** the separator char for this parser */ protected char fieldSep; /** parse: break the input String into fields * @return java.util.Iterator containing each field * from the original as a String, in order. */ public List parse(String line) { StringBuffer sb = new StringBuffer( ); list.clear( ); // recycle to initial state int i = 0; if (line.length( ) == 0) { list.add(line); return list; } do { sb.setLength(0); if (i < line.length( ) && line.charAt(i) == '"') i = advQuoted(line, sb, ++i); // skip quote else i = advPlain(line, sb, i); list.add(sb.toString( )); Debug.println("csv", sb.toString( )); i++; } while (i < line.length( )); return list; } /** advQuoted: quoted field; return index of next separator */ protected int advQuoted(String s, StringBuffer sb, int i) { int j; int len= s.length( ); for (j=i; j<len; j++) { if (s.charAt(j) == '"' && j+1 < len) { if (s.charAt(j+1) == '"') { j++; // skip escape char } else if (s.charAt(j+1) == fieldSep) { //next delimiter j++; // skip end quotes break; } } else if (s.charAt(j) == '"' && j+1 == len) { // end quotes at end of line break; //done } sb.append(s.charAt(j)); // regular character. } return j; } /** advPlain: unquoted field; return index of next separator */ protected int advPlain(String s, StringBuffer sb, int i) { int j; j = s.indexOf(fieldSep, i); // look for separator Debug.println("csv", "i = " + i + ", j = " + j); if (j == -1) { // none found sb.append(s.substring(i)); return s.length( ); } else { sb.append(s.substring(i, j)); return j; } } }