diff options
Diffstat (limited to 'contrib/dict_xsyn/dict_xsyn.c')
| -rw-r--r-- | contrib/dict_xsyn/dict_xsyn.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/contrib/dict_xsyn/dict_xsyn.c b/contrib/dict_xsyn/dict_xsyn.c new file mode 100644 index 0000000..1065d64 --- /dev/null +++ b/contrib/dict_xsyn/dict_xsyn.c @@ -0,0 +1,259 @@ +/*------------------------------------------------------------------------- + * + * dict_xsyn.c + * Extended synonym dictionary + * + * Copyright (c) 2007-2020, PostgreSQL Global Development Group + * + * IDENTIFICATION + * contrib/dict_xsyn/dict_xsyn.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include <ctype.h> + +#include "commands/defrem.h" +#include "tsearch/ts_locale.h" +#include "tsearch/ts_utils.h" + +PG_MODULE_MAGIC; + +typedef struct +{ + char *key; /* Word */ + char *value; /* Unparsed list of synonyms, including the + * word itself */ +} Syn; + +typedef struct +{ + int len; + Syn *syn; + + bool matchorig; + bool keeporig; + bool matchsynonyms; + bool keepsynonyms; +} DictSyn; + + +PG_FUNCTION_INFO_V1(dxsyn_init); +PG_FUNCTION_INFO_V1(dxsyn_lexize); + +static char * +find_word(char *in, char **end) +{ + char *start; + + *end = NULL; + while (*in && t_isspace(in)) + in += pg_mblen(in); + + if (!*in || *in == '#') + return NULL; + start = in; + + while (*in && !t_isspace(in)) + in += pg_mblen(in); + + *end = in; + + return start; +} + +static int +compare_syn(const void *a, const void *b) +{ + return strcmp(((const Syn *) a)->key, ((const Syn *) b)->key); +} + +static void +read_dictionary(DictSyn *d, const char *filename) +{ + char *real_filename = get_tsearch_config_filename(filename, "rules"); + tsearch_readline_state trst; + char *line; + int cur = 0; + + if (!tsearch_readline_begin(&trst, real_filename)) + ereport(ERROR, + (errcode(ERRCODE_CONFIG_FILE_ERROR), + errmsg("could not open synonym file \"%s\": %m", + real_filename))); + + while ((line = tsearch_readline(&trst)) != NULL) + { + char *value; + char *key; + char *pos; + char *end; + + if (*line == '\0') + continue; + + value = lowerstr(line); + pfree(line); + + pos = value; + while ((key = find_word(pos, &end)) != NULL) + { + /* Enlarge syn structure if full */ + if (cur == d->len) + { + d->len = (d->len > 0) ? 2 * d->len : 16; + if (d->syn) + d->syn = (Syn *) repalloc(d->syn, sizeof(Syn) * d->len); + else + d->syn = (Syn *) palloc(sizeof(Syn) * d->len); + } + + /* Save first word only if we will match it */ + if (pos != value || d->matchorig) + { + d->syn[cur].key = pnstrdup(key, end - key); + d->syn[cur].value = pstrdup(value); + + cur++; + } + + pos = end; + + /* Don't bother scanning synonyms if we will not match them */ + if (!d->matchsynonyms) + break; + } + + pfree(value); + } + + tsearch_readline_end(&trst); + + d->len = cur; + if (cur > 1) + qsort(d->syn, d->len, sizeof(Syn), compare_syn); + + pfree(real_filename); +} + +Datum +dxsyn_init(PG_FUNCTION_ARGS) +{ + List *dictoptions = (List *) PG_GETARG_POINTER(0); + DictSyn *d; + ListCell *l; + char *filename = NULL; + + d = (DictSyn *) palloc0(sizeof(DictSyn)); + d->len = 0; + d->syn = NULL; + d->matchorig = true; + d->keeporig = true; + d->matchsynonyms = false; + d->keepsynonyms = true; + + foreach(l, dictoptions) + { + DefElem *defel = (DefElem *) lfirst(l); + + if (strcmp(defel->defname, "matchorig") == 0) + { + d->matchorig = defGetBoolean(defel); + } + else if (strcmp(defel->defname, "keeporig") == 0) + { + d->keeporig = defGetBoolean(defel); + } + else if (strcmp(defel->defname, "matchsynonyms") == 0) + { + d->matchsynonyms = defGetBoolean(defel); + } + else if (strcmp(defel->defname, "keepsynonyms") == 0) + { + d->keepsynonyms = defGetBoolean(defel); + } + else if (strcmp(defel->defname, "rules") == 0) + { + /* we can't read the rules before parsing all options! */ + filename = defGetString(defel); + } + else + { + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("unrecognized xsyn parameter: \"%s\"", + defel->defname))); + } + } + + if (filename) + read_dictionary(d, filename); + + PG_RETURN_POINTER(d); +} + +Datum +dxsyn_lexize(PG_FUNCTION_ARGS) +{ + DictSyn *d = (DictSyn *) PG_GETARG_POINTER(0); + char *in = (char *) PG_GETARG_POINTER(1); + int length = PG_GETARG_INT32(2); + Syn word; + Syn *found; + TSLexeme *res = NULL; + + if (!length || d->len == 0) + PG_RETURN_POINTER(NULL); + + /* Create search pattern */ + { + char *temp = pnstrdup(in, length); + + word.key = lowerstr(temp); + pfree(temp); + word.value = NULL; + } + + /* Look for matching syn */ + found = (Syn *) bsearch(&word, d->syn, d->len, sizeof(Syn), compare_syn); + pfree(word.key); + + if (!found) + PG_RETURN_POINTER(NULL); + + /* Parse string of synonyms and return array of words */ + { + char *value = found->value; + char *syn; + char *pos; + char *end; + int nsyns = 0; + + res = palloc(sizeof(TSLexeme)); + + pos = value; + while ((syn = find_word(pos, &end)) != NULL) + { + res = repalloc(res, sizeof(TSLexeme) * (nsyns + 2)); + + /* The first word is output only if keeporig=true */ + if (pos != value || d->keeporig) + { + res[nsyns].lexeme = pnstrdup(syn, end - syn); + res[nsyns].nvariant = 0; + res[nsyns].flags = 0; + nsyns++; + } + + pos = end; + + /* Stop if we are not to output the synonyms */ + if (!d->keepsynonyms) + break; + } + res[nsyns].lexeme = NULL; + } + + PG_RETURN_POINTER(res); +} |