server/src/util/umlaut.c

/*
Copyright (c) 1998-2010, Enno Rehling <enno@eressea.de>
                         Katja Zedel <katze@felidae.kn-bremen.de
                         Christian Schlittchen <corwin@amber.kn-bremen.de>

Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
**/

#include <platform.h>
#include "umlaut.h"

#include "log.h"
#include "unicode.h"

#include <wctype.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

typedef struct tref {
  struct tref * nexthash;
  ucs4_t ucs;
  struct tnode * node;
} tref;

#define LEAF 1 /* leaf node for a word. always matches */
#define SHARED 2 /* at least two words share the node */

void
addtoken(tnode * root, const char * str, variant id)
{
  static const struct replace { /* STATIC_CONST: constant value */
    ucs4_t ucs;
    const char str[3];
  } replace[] = {
    /* match lower-case (!) umlauts and others to transcriptions */
    { 228, "AE"}, /* auml */
    { 246, "OE"}, /* ouml */
    { 252, "UE"}, /* uuml */
    { 223, "SS"}, /* szlig */
    { 230, "AE"}, /* norsk */
    { 248, "OE"}, /* norsk */
    { 229, "AA"}, /* norsk */
    { 0, "" }
  };

  if (!*str) {
    root->id = id;
    root->flags |= LEAF;
  } else {
    tref * next;
    int ret, index, i = 0;
    ucs4_t ucs, lcs;
    size_t len;

    ret = unicode_utf8_to_ucs4(&ucs, str, &len);
    assert(ret==0 || !"invalid utf8 string");
    lcs = ucs;

#if NODEHASHSIZE == 8
    index = ucs & 7;
#else
    index = ucs % NODEHASHSIZE;
#endif
    assert(index>=0);
    next = root->next[index];
    if (!(root->flags & LEAF)) root->id = id;
    while (next && next->ucs != ucs) next = next->nexthash;
    if (!next) {
      tref * ref;
      tnode * node = calloc(1, sizeof(tnode));

      if (ucs<'a' || ucs>'z') {
        lcs = towlower((wint_t)ucs);
      }
      if (ucs==lcs) {
        ucs = towupper((wint_t)ucs);
      }

      ref = malloc(sizeof(tref));
      ref->ucs = ucs;
      ref->node = node;
      ref->nexthash=root->next[index];
      root->next[index] = ref;

      /* try lower/upper casing the character, and try again */
      if (ucs!=lcs) {
#if NODEHASHSIZE == 8
        index = lcs & 7;
#else
        index = lcs % NODEHASHSIZE;
#endif
        ref = malloc(sizeof(tref));
        ref->ucs = lcs;
        ref->node = node;
        ref->nexthash = root->next[index];
        root->next[index] = ref;
      }
      next=ref;
    } else {
      next->node->flags |= SHARED;
      if ((next->node->flags & LEAF) == 0) next->node->id.v = NULL; /* why?*/
    }
    addtoken(next->node, str+len, id);
    while (replace[i].str[0]) {
      if (lcs==replace[i].ucs) {
        char zText[1024];
        memcpy(zText, replace[i].str, 3);
        strcpy(zText+2, (const char*)str+len);
        addtoken(root, zText, id);
        break;
      }
      ++i;
    }
  }
}

int
findtoken(const tnode * tk, const char * str, variant* result)
{
  if (!str || *str==0) return E_TOK_NOMATCH;

  do {
    int index;
    const tref * ref;
    ucs4_t ucs;
    size_t len;
    int ret = unicode_utf8_to_ucs4(&ucs, str, &len);

    if (ret!=0) {
      /* encoding is broken. youch */
      return E_TOK_NOMATCH;
    }
#if NODEHASHSIZE == 8
    index = ucs & 7;
#else
    index = ucs % NODEHASHSIZE;
#endif
    ref = tk->next[index];
    while (ref && ref->ucs!=ucs) ref = ref->nexthash;
    str+=len;
    if (!ref) return E_TOK_NOMATCH;
    tk = ref->node;
  } while (*str);
  if (tk) {
    *result = tk->id;
    return E_TOK_SUCCESS;
  }
  return E_TOK_NOMATCH;
}