+/* This file is part of the YAZ toolkit.
+ * Copyright (C) 1995-2013 Index Data
+ * See the file LICENSE for details.
+ */
+/**
+ * \file stemmer.c
+ * \brief Implements stemmer wrapper
+ */
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#if YAZ_HAVE_ICU
#include <yaz/stemmer.h>
+#include <yaz/xmalloc.h>
+
+#include <libstemmer.h>
+
#include <unicode/ustring.h> /* some more string fcns*/
#include <unicode/uchar.h> /* char names */
+enum stemmer_implementation {
+ yaz_no_operation,
+ yaz_snowball
+};
struct yaz_stemmer_t
{
int implementation;
- union {
- struct sb_stemmer *snowballer;
- };
+ // Required for cloning.
+ char *locale;
+ char *rule;
+ struct sb_stemmer *sb_stemmer;
};
+const char* yaz_stemmer_lookup_charenc(const char *charenc, const char *rule) {
+ return "UTF_8";
+}
+
+const char* yaz_stemmer_lookup_algorithm(const char *locale, const char *rule) {
+ return locale;
+}
+
+yaz_stemmer_p yaz_stemmer_snowball_create(const char *locale, const char *rule, UErrorCode *status) {
+ const char *charenc = yaz_stemmer_lookup_charenc(locale, rule);
+ const char *algorithm = yaz_stemmer_lookup_algorithm(locale,rule);
+ struct sb_stemmer *stemmer = sb_stemmer_new(algorithm, charenc);
+ yaz_stemmer_p yaz_stemmer;
+ if (stemmer == 0) {
+ *status = U_ILLEGAL_ARGUMENT_ERROR;
+ yaz_log(YLOG_FATAL, "yaz_stemmer: Failed to create snowball stemmer from locale %srule %s. Showball: charenc %s algorithm %s ",
+ locale, rule, charenc, algorithm);
+ return 0;
+ }
+ yaz_log(YLOG_DEBUG, "created snowball stemmer: algorithm %s charenc %s ", algorithm, charenc);
+ yaz_stemmer = xmalloc(sizeof(*yaz_stemmer));
+ yaz_stemmer->implementation = yaz_snowball;
+
+ yaz_stemmer->locale = xstrdup(locale);
+ yaz_stemmer->rule = xstrdup(rule);
+ yaz_stemmer->sb_stemmer = stemmer;
+ yaz_log(YLOG_DEBUG, "created snowball stemmer: algorithm %s charenc %s ", algorithm, charenc);
+ return yaz_stemmer;
+}
+
yaz_stemmer_p yaz_stemmer_create(const char *locale, const char *rule, UErrorCode *status) {
- return 0;
+ *status = U_ZERO_ERROR;
+ // dispatch logic required if more algorithms is implemented.
+ yaz_log(YLOG_DEBUG, "create stemmer: locale %s rule %s ", locale, rule);
+ return yaz_stemmer_snowball_create(locale, rule, status);
}
yaz_stemmer_p yaz_stemmer_clone(yaz_stemmer_p stemmer) {
- return 0;
+ UErrorCode error = U_ZERO_ERROR;
+ if (stemmer == 0)
+ return 0;
+ return yaz_stemmer_create(stemmer->locale, stemmer->rule, &error);
}
-void yaz_stemmer_stem(yaz_stemmer_p stemmer, struct icu_buf_utf16 *dst, struct icu_buf_utf16* src, UErrorCode *status) {
+void yaz_stemmer_stem(yaz_stemmer_p stemmer, struct icu_buf_utf16 *dst, struct icu_buf_utf16* src, UErrorCode *status)
+{
+ switch(stemmer->implementation) {
+ case yaz_snowball: {
+ struct icu_buf_utf8 *utf8_buf = icu_buf_utf8_create(0);
+ icu_utf16_to_utf8(utf8_buf, src, status);
+ if (*status == U_ZERO_ERROR) {
+ const sb_symbol *cstr = (const sb_symbol*) icu_buf_utf8_to_cstr(utf8_buf);
+ const sb_symbol *sb_symbol = sb_stemmer_stem(stemmer->sb_stemmer, cstr, utf8_buf->utf8_len);
+ if (sb_symbol == 0) {
+ icu_buf_utf16_copy(dst, src);
+ }
+ else {
+ const char *cstr2 = (const char *) sb_symbol;
+ icu_utf16_from_utf8_cstr(dst, cstr2 , status);
+#if 0
+ yaz_log(YLOG_DEBUG, "stemming %s to %s ", cstr, cstr2);
+#endif
+ }
+ }
+ icu_buf_utf8_destroy(utf8_buf);
+ return ;
+ break;
+ }
+ case yaz_no_operation:
+ yaz_log(YLOG_DEBUG, "Stemmer (No operation) called");
+ default: {
+ // Default return the same as given.
+ icu_buf_utf16_copy(dst, src);
+ }
+ }
}
-void yaz_stemmer_destroy(yaz_stemmer_p stemmer) {
-
+void yaz_stemmer_destroy(yaz_stemmer_p stemmer)
+{
+ /* Handle no stemmer correctly */
+ if (stemmer == 0)
+ return ;
+ switch (stemmer->implementation) {
+ case yaz_snowball:
+ sb_stemmer_delete(stemmer->sb_stemmer);
+ break;
+ }
+ xfree(stemmer->locale);
+ xfree(stemmer->rule);
+ xfree(stemmer);
}
+#endif /* YAZ_HAVE_ICU */