Stemming

Question

Hi,
Can someone explain the code in the folloiwng- I need a detailed explanation
class Stemmer
{  private char[] b;
private int i, /* offset into b */
i_end, /* offset to end of stemmed word */
j, k;
private static final int INC = 50;
/* unit of size whereby b is increased */
public Stemmer()
{  b = new char[INC];
i = 0;
i_end = 0;
* Add a character to the word being stemmed. When you are finished
* adding characters, you can call stem(void) to stem the word.
public void add(char ch)
{  if (i == b.length)
{  char[] new_b = new char[i+INC];
for (int c = 0; c < i; c++) new_b[c] = b[c];
b = new_b;
b[i++] = ch;
/** Adds wLen characters to the word being stemmed contained in a portion
* of a char[] array. This is like repeated calls of add(char ch), but
* faster.
public void add(char[] w, int wLen)
{  if (i+wLen >= b.length)
{  char[] new_b = new char[i+wLen+INC];
for (int c = 0; c < i; c++) new_b[c] = b[c];
b = new_b;
for (int c = 0; c < wLen; c++) b[i++] = w[c];
* After a word has been stemmed, it can be retrieved by toString(),
* or a reference to the internal buffer can be retrieved by getResultBuffer
* and getResultLength (which is generally more efficient.)
public String toString() { return new String(b,0,i_end); }
* Returns the length of the word resulting from the stemming process.
public int getResultLength() { return i_end; }
* Returns a reference to a character buffer containing the results of
* the stemming process. You also need to consult getResultLength()
* to determine the length of the result.
public char[] getResultBuffer() { return b; }
/* cons(i) is true <=> b[i] is a consonant. */
private final boolean cons(int i)
{  switch (b[i])
{  case 'a': case 'e': case 'i': case 'o': case 'u': return false;
case 'y': return (i==0) ? true : !cons(i-1);
default: return true;
/* m() measures the number of consonant sequences between 0 and j. if c is
a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
presence,
<c><v> gives 0
<c>vc<v> gives 1
<c>vcvc<v> gives 2
<c>vcvcvc<v> gives 3
private final int m()
{  int n = 0;
int i = 0;
while(true)
{  if (i > j) return n;
if (! cons(i)) break; i++;
i++;
while(true)
{  while(true)
{  if (i > j) return n;
if (cons(i)) break;
i++;
i++;
n++;
while(true)
{  if (i > j) return n;
if (! cons(i)) break;
i++;
i++;
/* vowelinstem() is true <=> 0,...j contains a vowel */
private final boolean vowelinstem()
{  int i; for (i = 0; i <= j; i++) if (! cons(i)) return true;
return false;
/* doublec(j) is true <=> j,(j-1) contain a double consonant. */
private final boolean doublec(int j)
{  if (j < 1) return false;
if (b[j] != b[j-1]) return false;
return cons(j);
/* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
and also if the second c is not w,x or y. this is used when trying to
restore an e at the end of a short word. e.g.
cav(e), lov(e), hop(e), crim(e), but
snow, box, tray.
private final boolean cvc(int i)
{  if (i < 2 || !cons(i) || cons(i-1) || !cons(i-2)) return false;
{  int ch = b[i];
if (ch == 'w' || ch == 'x' || ch == 'y') return false;
return true;
private final boolean ends(String s)
{  int l = s.length();
int o = k-l+1;
if (o < 0) return false;
for (int i = 0; i < l; i++) if (b[o+i] != s.charAt(i)) return false;
j = k-l;
return true;
/* setto(s) sets (j+1),...k to the characters in the string s, readjusting
k. */
private final void setto(String s)
{  int l = s.length();
int o = j+1;
for (int i = 0; i < l; i++) b[o+i] = s.charAt(i);
k = j+l;
}

Answer 1

Use code tags when posting code.
I would suggest and some println()s and then running the code.