- If one attempts to access the last character as - follows: -
- StringBuffer sb = ...; - ... - PartialBuffer pb = new PartialBuffer(sb); - char c = pb.charAt(pb.length()-1); -- then two things happen. First, a zero is returned - into the variable c. Second, the overRun flag is - set to "true." Accessing data beyond the end of - the buffer is considered an "overRun" of the data. -
- This can be helpful in determining whether more - characters are required for a match to occur, as - the pseudo-code below illustrates. -
- int i = ...;
- Regex r = new Regex("some pattern");
- pb.allowOverRun = true;
- pb.overRun = true;
- boolean result = r.matchAt(pb,i);
- if(pb.overRun) {
- // The result of the match is not relevant, regardless
- // of whether result is true or false. We need to
- // append more data to the buffer and try again.
- ....
- sb.append(more data);
- }
-
- */
-class PartialBuffer
- implements StringLike
-{
- int off;
- public boolean allowOverRun = true;
- public boolean overRun = false;
- StringBuffer sb;
- PartialBuffer(StringBuffer sb)
- {
- this.sb = sb;
- }
-
- public char charAt(int n)
- {
- n += off;
- if (n == sb.length())
- {
- overRun = true;
- return 0;
- }
- return sb.charAt(n);
- }
-
- public int length()
- {
- return allowOverRun ? sb.length() + 1 : sb.length();
- }
-
- public int indexOf(char c)
- {
- for (int i = 0; i < sb.length(); i++)
- {
- if (sb.charAt(i) == c)
- {
- return i;
- }
- }
- return -1;
- }
-
- public Object unwrap()
- {
- return sb;
- }
-
- public String substring(int i1, int i2)
- {
- StringBuffer sb = new StringBuffer(i2 - i1);
- for (int i = i1; i < i2; i++)
- {
- sb.append(charAt(i));
- }
- return sb.toString();
- }
-
- /** Just returns null. */
- public BasicStringBufferLike newStringBufferLike()
- {
- return null;
- }
-}
+//
+// This software is now distributed according to
+// the Lesser Gnu Public License. Please see
+// http://www.gnu.org/copyleft/lesser.txt for
+// the details.
+// -- Happy Computing!
+//
+package com.stevesoft.pat;
+
+/**
+ * This class allows you to match on a partial string. If the allowOverRun flag
+ * is true, then the length() method returns a number 1 larger than is actually
+ * contained by the class.
+ * + * If one attempts to access the last character as follows: + * + *
+ * StringBuffer sb = ...; + * ... + * PartialBuffer pb = new PartialBuffer(sb); + * char c = pb.charAt(pb.length()-1); + *+ * + * then two things happen. First, a zero is returned into the variable c. + * Second, the overRun flag is set to "true." Accessing data beyond the end of + * the buffer is considered an "overRun" of the data. + *
+ * This can be helpful in determining whether more characters are required for a + * match to occur, as the pseudo-code below illustrates. + * + *
+ * int i = ...;
+ * Regex r = new Regex("some pattern");
+ * pb.allowOverRun = true;
+ * pb.overRun = true;
+ * boolean result = r.matchAt(pb,i);
+ * if(pb.overRun) {
+ * // The result of the match is not relevant, regardless
+ * // of whether result is true or false. We need to
+ * // append more data to the buffer and try again.
+ * ....
+ * sb.append(more data);
+ * }
+ *
+ */
+class PartialBuffer implements StringLike
+{
+ int off;
+
+ public boolean allowOverRun = true;
+
+ public boolean overRun = false;
+
+ StringBuffer sb;
+
+ PartialBuffer(StringBuffer sb)
+ {
+ this.sb = sb;
+ }
+
+ public char charAt(int n)
+ {
+ n += off;
+ if (n == sb.length())
+ {
+ overRun = true;
+ return 0;
+ }
+ return sb.charAt(n);
+ }
+
+ public int length()
+ {
+ return allowOverRun ? sb.length() + 1 : sb.length();
+ }
+
+ public int indexOf(char c)
+ {
+ for (int i = 0; i < sb.length(); i++)
+ {
+ if (sb.charAt(i) == c)
+ {
+ return i;
+ }
+ }
+ return -1;
+ }
+
+ public Object unwrap()
+ {
+ return sb;
+ }
+
+ public String substring(int i1, int i2)
+ {
+ StringBuffer sb = new StringBuffer(i2 - i1);
+ for (int i = i1; i < i2; i++)
+ {
+ sb.append(charAt(i));
+ }
+ return sb.toString();
+ }
+
+ /** Just returns null. */
+ public BasicStringBufferLike newStringBufferLike()
+ {
+ return null;
+ }
+}