#include "getword.h"

char *GetWord::run(char **s, size_t *len)
{
  size_t bytes;
  char *t, *u;
  int offset;

  t = *s;

  while (*t)
  {
    if (GetWord::isWordCharacter(t, &bytes))
		{
      for (u = t; *u;)
      {
        if (!GetWord::isWordCharacter(u, &bytes))
        {
          *len = u - t;	
          offset = t - *s;
          *s += *len + offset + bytes;
          return t;
        }
        else
          u += bytes;
      }
      if (*t && !(*u))
      {
        *len = u - t;
        offset = t - *s;
        *s = u;
        return t;
      }
      t = u;
    }
    else
      t += bytes;
  }
  return NULL;
}

bool GetWord::isWordCharacter(char *s, size_t *bytes)
{
  *bytes = 0;
  
  unsigned char *us = (unsigned char *)s;
  if (
    *us < 65 ||
    (*us > 90 && *us < 97) ||
    (*us > 123 && *us < 128)
  )
  {
    *bytes = 1;
    return false;
  }

  // check for UTF-8 byte sequences
  else if (*us > 127)
  {
    // determine length
    unsigned char *it = us;
    for (; *it > 127; ++it)
      ++(*bytes);
    
    // Unicode punctuation marks
    // Based on http://www1.tip.nl/~t876506/utf8tbl.html
    return (
      *us == 226 && *(us + 1) == 128 ||
      *us == 194 ||
      *us == 203
    ) ? false : true;
  }
  else
  {
    *bytes = 1;
    return true;
  }
}