*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.151 2006/10/04 00:30:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.152 2006/10/07 00:11:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
typedef struct varlena unknown;
+typedef struct
+{
+ bool use_wchar; /* T if multibyte encoding */
+ char *str1; /* use these if not use_wchar */
+ char *str2; /* note: these point to original texts */
+ pg_wchar *wstr1; /* use these if use_wchar */
+ pg_wchar *wstr2; /* note: these are palloc'd */
+ int len1; /* string lengths in logical characters */
+ int len2;
+} TextPositionState;
+
#define DatumGetUnknownP(X) ((unknown *) PG_DETOAST_DATUM(X))
#define DatumGetUnknownPCopy(X) ((unknown *) PG_DETOAST_DATUM_COPY(X))
#define PG_GETARG_UNKNOWN_P(n) DatumGetUnknownP(PG_GETARG_DATUM(n))
DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(str_)))
#define TEXTLEN(textp) \
text_length(PointerGetDatum(textp))
-#define TEXTPOS(buf_text, from_sub_text) \
- text_position(buf_text, from_sub_text, 1)
-#define LEFT(buf_text, from_sub_text) \
- text_substring(PointerGetDatum(buf_text), \
- 1, \
- TEXTPOS(buf_text, from_sub_text) - 1, false)
static int text_cmp(text *arg1, text *arg2);
static int32 text_length(Datum str);
-static int32 text_position(text *t1, text *t2, int matchnum);
+static int text_position(text *t1, text *t2);
+static void text_position_setup(text *t1, text *t2, TextPositionState *state);
+static int text_position_next(int start_pos, TextPositionState *state);
+static void text_position_cleanup(TextPositionState *state);
static text *text_substring(Datum str,
int32 start,
int32 length,
text *str = PG_GETARG_TEXT_P(0);
text *search_str = PG_GETARG_TEXT_P(1);
- PG_RETURN_INT32(text_position(str, search_str, 1));
+ PG_RETURN_INT32((int32) text_position(str, search_str));
}
/*
* Inputs:
* t1 - string to be searched
* t2 - pattern to match within t1
- * matchnum - number of the match to be found (1 is the first match)
* Result:
* Character index of the first matched char, starting from 1,
* or 0 if no match.
* This is broken out so it can be called directly by other string processing
* functions.
*/
-static int32
-text_position(text *t1, text *t2, int matchnum)
+static int
+text_position(text *t1, text *t2)
{
- int match = 0,
- pos = 0,
- p,
- px,
- len1,
- len2;
+ TextPositionState state;
+ int result;
- if (matchnum <= 0)
- return 0; /* result for 0th match */
+ text_position_setup(t1, t2, &state);
+ result = text_position_next(1, &state);
+ text_position_cleanup(&state);
+ return result;
+}
- if (VARSIZE(t2) <= VARHDRSZ)
- return 1; /* result for empty pattern */
+/*
+ * text_position_setup, text_position_next, text_position_cleanup -
+ * Component steps of text_position()
+ *
+ * These are broken out so that a string can be efficiently searched for
+ * multiple occurrences of the same pattern. text_position_next may be
+ * called multiple times with increasing values of start_pos, which is
+ * the 1-based character position to start the search from. The "state"
+ * variable is normally just a local variable in the caller.
+ */
- len1 = VARSIZE(t1) - VARHDRSZ;
- len2 = VARSIZE(t2) - VARHDRSZ;
+static void
+text_position_setup(text *t1, text *t2, TextPositionState *state)
+{
+ int len1 = VARSIZE(t1) - VARHDRSZ;
+ int len2 = VARSIZE(t2) - VARHDRSZ;
if (pg_database_encoding_max_length() == 1)
{
/* simple case - single byte encoding */
- char *p1,
+ state->use_wchar = false;
+ state->str1 = VARDATA(t1);
+ state->str2 = VARDATA(t2);
+ state->len1 = len1;
+ state->len2 = len2;
+ }
+ else
+ {
+ /* not as simple - multibyte encoding */
+ pg_wchar *p1,
*p2;
- p1 = VARDATA(t1);
- p2 = VARDATA(t2);
+ p1 = (pg_wchar *) palloc((len1 + 1) * sizeof(pg_wchar));
+ len1 = pg_mb2wchar_with_len(VARDATA(t1), p1, len1);
+ p2 = (pg_wchar *) palloc((len2 + 1) * sizeof(pg_wchar));
+ len2 = pg_mb2wchar_with_len(VARDATA(t2), p2, len2);
+
+ state->use_wchar = true;
+ state->wstr1 = p1;
+ state->wstr2 = p2;
+ state->len1 = len1;
+ state->len2 = len2;
+ }
+}
+
+static int
+text_position_next(int start_pos, TextPositionState *state)
+{
+ int pos = 0,
+ p,
+ px;
+
+ Assert(start_pos > 0); /* else caller error */
+
+ if (state->len2 <= 0)
+ return start_pos; /* result for empty pattern */
+
+ if (!state->use_wchar)
+ {
+ /* simple case - single byte encoding */
+ char *p1 = state->str1;
+ char *p2 = state->str2;
/* no use in searching str past point where search_str will fit */
- px = (len1 - len2);
+ px = (state->len1 - state->len2);
+
+ p1 += start_pos - 1;
- for (p = 0; p <= px; p++)
+ for (p = start_pos - 1; p <= px; p++)
{
- if ((*p1 == *p2) && (strncmp(p1, p2, len2) == 0))
+ if ((*p1 == *p2) && (strncmp(p1, p2, state->len2) == 0))
{
- if (++match == matchnum)
- {
- pos = p + 1;
- break;
- }
+ pos = p + 1;
+ break;
}
p1++;
}
else
{
/* not as simple - multibyte encoding */
- pg_wchar *p1,
- *p2,
- *ps1,
- *ps2;
-
- ps1 = p1 = (pg_wchar *) palloc((len1 + 1) * sizeof(pg_wchar));
- (void) pg_mb2wchar_with_len(VARDATA(t1), p1, len1);
- len1 = pg_wchar_strlen(p1);
- ps2 = p2 = (pg_wchar *) palloc((len2 + 1) * sizeof(pg_wchar));
- (void) pg_mb2wchar_with_len(VARDATA(t2), p2, len2);
- len2 = pg_wchar_strlen(p2);
+ pg_wchar *p1 = state->wstr1;
+ pg_wchar *p2 = state->wstr2;
/* no use in searching str past point where search_str will fit */
- px = (len1 - len2);
+ px = (state->len1 - state->len2);
- for (p = 0; p <= px; p++)
+ p1 += start_pos - 1;
+
+ for (p = start_pos - 1; p <= px; p++)
{
- if ((*p1 == *p2) && (pg_wchar_strncmp(p1, p2, len2) == 0))
+ if ((*p1 == *p2) && (pg_wchar_strncmp(p1, p2, state->len2) == 0))
{
- if (++match == matchnum)
- {
- pos = p + 1;
- break;
- }
+ pos = p + 1;
+ break;
}
p1++;
}
-
- pfree(ps1);
- pfree(ps2);
}
return pos;
}
+static void
+text_position_cleanup(TextPositionState *state)
+{
+ if (state->use_wchar)
+ {
+ pfree(state->wstr1);
+ pfree(state->wstr2);
+ }
+}
+
/* varstr_cmp()
* Comparison function for text strings with given lengths.
* Includes locale support, but must copy strings to temporary memory
#define PG_STR_GET_BYTEA(str_) \
DatumGetByteaP(DirectFunctionCall1(byteain, CStringGetDatum(str_)))
+
/*
* bytea_substr()
* Return a substring starting at the specified position.
text *to_sub_text = PG_GETARG_TEXT_P(2);
int src_text_len = TEXTLEN(src_text);
int from_sub_text_len = TEXTLEN(from_sub_text);
- text *left_text;
- text *right_text;
- text *buf_text;
+ TextPositionState state;
+ text *chunk_text;
text *ret_text;
+ int start_posn;
int curr_posn;
StringInfoData str;
if (src_text_len == 0 || from_sub_text_len == 0)
PG_RETURN_TEXT_P(src_text);
- curr_posn = TEXTPOS(src_text, from_sub_text);
+ text_position_setup(src_text, from_sub_text, &state);
+
+ start_posn = 1;
+ curr_posn = text_position_next(1, &state);
/* When the from_sub_text is not found, there is nothing to do. */
if (curr_posn == 0)
+ {
+ text_position_cleanup(&state);
PG_RETURN_TEXT_P(src_text);
+ }
initStringInfo(&str);
- buf_text = src_text;
- while (curr_posn > 0)
+ do
{
- left_text = text_substring(PointerGetDatum(buf_text),
- 1, curr_posn - 1, false);
- right_text = text_substring(PointerGetDatum(buf_text),
- curr_posn + from_sub_text_len, -1, true);
+ chunk_text = text_substring(PointerGetDatum(src_text),
+ start_posn,
+ curr_posn - start_posn,
+ false);
+ appendStringInfoText(&str, chunk_text);
+ pfree(chunk_text);
- appendStringInfoText(&str, left_text);
appendStringInfoText(&str, to_sub_text);
- if (buf_text != src_text)
- pfree(buf_text);
- pfree(left_text);
- buf_text = right_text;
- curr_posn = TEXTPOS(buf_text, from_sub_text);
+ start_posn = curr_posn + from_sub_text_len;
+ curr_posn = text_position_next(start_posn, &state);
}
+ while (curr_posn > 0);
+
+ /* copy trailing chunk */
+ chunk_text = text_substring(PointerGetDatum(src_text),
+ start_posn,
+ -1,
+ true);
+ appendStringInfoText(&str, chunk_text);
+ pfree(chunk_text);
- appendStringInfoText(&str, buf_text);
- if (buf_text != src_text)
- pfree(buf_text);
+ text_position_cleanup(&state);
ret_text = PG_STR_GET_TEXT(str.data);
pfree(str.data);
int fldnum = PG_GETARG_INT32(2);
int inputstring_len = TEXTLEN(inputstring);
int fldsep_len = TEXTLEN(fldsep);
+ TextPositionState state;
int start_posn;
int end_posn;
text *result_text;
PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
}
- start_posn = text_position(inputstring, fldsep, fldnum - 1);
- end_posn = text_position(inputstring, fldsep, fldnum);
+ text_position_setup(inputstring, fldsep, &state);
- if ((start_posn == 0) && (end_posn == 0)) /* fldsep not found */
+ /* identify bounds of first field */
+ start_posn = 1;
+ end_posn = text_position_next(1, &state);
+
+ /* special case if fldsep not found at all */
+ if (end_posn == 0)
{
- /* if first field, return input string, else empty string */
+ text_position_cleanup(&state);
+ /* if field 1 requested, return input string, else empty string */
if (fldnum == 1)
PG_RETURN_TEXT_P(inputstring);
else
PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
}
- else if (start_posn == 0)
+
+ while (end_posn > 0 && --fldnum > 0)
{
- /* first field requested */
- result_text = LEFT(inputstring, fldsep);
- PG_RETURN_TEXT_P(result_text);
+ /* identify bounds of next field */
+ start_posn = end_posn + fldsep_len;
+ end_posn = text_position_next(start_posn, &state);
}
- else if (end_posn == 0)
+
+ text_position_cleanup(&state);
+
+ if (fldnum > 0)
{
- /* last field requested */
- result_text = text_substring(PointerGetDatum(inputstring),
- start_posn + fldsep_len,
- -1, true);
- PG_RETURN_TEXT_P(result_text);
+ /* N'th field separator not found */
+ /* if last field requested, return it, else empty string */
+ if (fldnum == 1)
+ result_text = text_substring(PointerGetDatum(inputstring),
+ start_posn,
+ -1,
+ true);
+ else
+ result_text = PG_STR_GET_TEXT("");
}
else
{
- /* interior field requested */
+ /* non-last field requested */
result_text = text_substring(PointerGetDatum(inputstring),
- start_posn + fldsep_len,
- end_posn - start_posn - fldsep_len,
+ start_posn,
+ end_posn - start_posn,
false);
- PG_RETURN_TEXT_P(result_text);
}
+
+ PG_RETURN_TEXT_P(result_text);
}
/*
text *fldsep = PG_GETARG_TEXT_P(1);
int inputstring_len = TEXTLEN(inputstring);
int fldsep_len = TEXTLEN(fldsep);
+ TextPositionState state;
int fldnum;
int start_posn;
int end_posn;
*/
if (fldsep_len < 1)
PG_RETURN_ARRAYTYPE_P(create_singleton_array(fcinfo, TEXTOID,
- CStringGetDatum(inputstring), 1));
+ PointerGetDatum(inputstring), 1));
- /* start with end position holding the initial start position */
- end_posn = 0;
+ text_position_setup(inputstring, fldsep, &state);
+
+ start_posn = 1;
for (fldnum = 1;; fldnum++) /* field number is 1 based */
{
- Datum dvalue;
- bool disnull = false;
-
- start_posn = end_posn;
- end_posn = text_position(inputstring, fldsep, fldnum);
+ end_posn = text_position_next(start_posn, &state);
- if ((start_posn == 0) && (end_posn == 0)) /* fldsep not found */
+ if (end_posn == 0)
{
- if (fldnum == 1)
- {
- /*
- * first element return one element, 1D, array using the input
- * string
- */
- PG_RETURN_ARRAYTYPE_P(create_singleton_array(fcinfo, TEXTOID,
- CStringGetDatum(inputstring), 1));
- }
- else
- {
- /* otherwise create array and exit */
- PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate,
- CurrentMemoryContext));
- }
- }
- else if (start_posn == 0)
- {
- /* first field requested */
- result_text = LEFT(inputstring, fldsep);
- }
- else if (end_posn == 0)
- {
- /* last field requested */
+ /* fetch last field */
result_text = text_substring(PointerGetDatum(inputstring),
- start_posn + fldsep_len,
- -1, true);
+ start_posn,
+ -1,
+ true);
}
else
{
- /* interior field requested */
+ /* fetch non-last field */
result_text = text_substring(PointerGetDatum(inputstring),
- start_posn + fldsep_len,
- end_posn - start_posn - fldsep_len,
+ start_posn,
+ end_posn - start_posn,
false);
}
- /* stash away current value */
- dvalue = PointerGetDatum(result_text);
- astate = accumArrayResult(astate, dvalue,
- disnull, TEXTOID,
+ /* stash away this field */
+ astate = accumArrayResult(astate,
+ PointerGetDatum(result_text),
+ false,
+ TEXTOID,
CurrentMemoryContext);
+
+ if (end_posn == 0)
+ break;
+ start_posn = end_posn + fldsep_len;
}
- /* never reached -- keep compiler quiet */
- PG_RETURN_NULL();
+ text_position_cleanup(&state);
+
+ PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate,
+ CurrentMemoryContext));
}
/*
projects / thirdparty / postgresql.git / commitdiff
