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Code review for regexp_replace patch. Improve documentation and comments,

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fix problems with replacement-string backslashes that aren't followed by
one of the expected characters, avoid giving the impression that
replace_text_regexp() is meant to be called directly as a SQL function,
etc.
This commit is contained in:
Tom Lane
2005-10-18 20:38:58 +00:00
parent 800af89004
commit 220f2a7d15
4 changed files with 146 additions and 112 deletions
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132
src/backend/utils/adt/varlena.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.137 2005/10/17 16:24:19 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.138 2005/10/18 20:38:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -24,11 +24,11 @@
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "parser/scansup.h"
#include "regex/regex.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/pg_locale.h"
#include "regex/regex.h"
typedef struct varlena unknown;
@ -2066,7 +2066,8 @@ replace_text(PG_FUNCTION_ARGS)
/*
* check_replace_text_has_escape_char
* check whether replace_text has escape char.
*
* check whether replace_text contains escape char.
*/
static bool
check_replace_text_has_escape_char(const text *replace_text)
@ -2077,14 +2078,18 @@ check_replace_text_has_escape_char(const text *replace_text)
if (pg_database_encoding_max_length() == 1)
{
for (; p < p_end; p++)
{
if (*p == '\\')
return true;
}
}
else
{
for (; p < p_end; p += pg_mblen(p))
{
if (*p == '\\')
return true;
}
}
return false;
@ -2092,7 +2097,9 @@ check_replace_text_has_escape_char(const text *replace_text)
/*
* appendStringInfoRegexpSubstr
* append string by using back references of regexp.
*
* Append replace_text to str, substituting regexp back references for
* \n escapes.
*/
static void
appendStringInfoRegexpSubstr(StringInfo str, text *replace_text,
@ -2100,50 +2107,41 @@ appendStringInfoRegexpSubstr(StringInfo str, text *replace_text,
{
const char *p = VARDATA(replace_text);
const char *p_end = p + (VARSIZE(replace_text) - VARHDRSZ);
int eml = pg_database_encoding_max_length();
int substr_start = 1;
int ch_cnt;
int so;
int eo;
while (1)
for (;;)
{
/* Find escape char. */
ch_cnt = 0;
const char *chunk_start = p;
int so;
int eo;
/* Find next escape char. */
if (eml == 1)
{
for (; p < p_end && *p != '\\'; p++)
ch_cnt++;
/* nothing */ ;
}
else
{
for (; p < p_end && *p != '\\'; p += pg_mblen(p))
ch_cnt++;
/* nothing */ ;
}
/*
* Copy the text when there is a text in the left of escape char or
* escape char is not found.
*/
if (ch_cnt)
{
text *append_text = text_substring(PointerGetDatum(replace_text),
substr_start, ch_cnt, false);
/* Copy the text we just scanned over, if any. */
if (p > chunk_start)
appendBinaryStringInfo(str, chunk_start, p - chunk_start);
appendStringInfoText(str, append_text);
pfree(append_text);
}
substr_start += ch_cnt + 1;
if (p >= p_end) /* When escape char is not found. */
/* Done if at end of string, else advance over escape char. */
if (p >= p_end)
break;
/* See the next character of escape char. */
p++;
so = eo = -1;
if (p >= p_end)
{
/* Escape at very end of input. Treat same as unexpected char */
appendStringInfoChar(str, '\\');
break;
}
if (*p >= '1' && *p <= '9')
{
@ -2153,7 +2151,6 @@ appendStringInfoRegexpSubstr(StringInfo str, text *replace_text,
so = pmatch[idx].rm_so;
eo = pmatch[idx].rm_eo;
p++;
substr_start++;
}
else if (*p == '&')
{
@ -2161,15 +2158,36 @@ appendStringInfoRegexpSubstr(StringInfo str, text *replace_text,
so = pmatch[0].rm_so;
eo = pmatch[0].rm_eo;
p++;
substr_start++;
}
else if (*p == '\\')
{
/* \\ means transfer one \ to output. */
appendStringInfoChar(str, '\\');
p++;
continue;
}
else
{
/*
* If escape char is not followed by any expected char,
* just treat it as ordinary data to copy. (XXX would it be
* better to throw an error?)
*/
appendStringInfoChar(str, '\\');
continue;
}
if (so != -1 && eo != -1)
{
/* Copy the text that is back reference of regexp. */
text *append_text = text_substring(PointerGetDatum(src_text),
so + 1, (eo - so), false);
/*
* Copy the text that is back reference of regexp. Because so and
* eo are counted in characters not bytes, it's easiest to use
* text_substring to pull out the correct chunk of text.
*/
text *append_text;
append_text = text_substring(PointerGetDatum(src_text),
so + 1, (eo - so), false);
appendStringInfoText(str, append_text);
pfree(append_text);
}
@ -2180,17 +2198,19 @@ appendStringInfoRegexpSubstr(StringInfo str, text *replace_text,
/*
* replace_text_regexp
*
* replace text that matches to regexp in src_text to replace_text.
*
* Note: to avoid having to include regex.h in builtins.h, we declare
* the regexp argument as void *, but really it's regex_t *.
*/
Datum
replace_text_regexp(PG_FUNCTION_ARGS)
text *
replace_text_regexp(text *src_text, void *regexp,
text *replace_text, bool glob)
{
text *ret_text;
text *src_text = PG_GETARG_TEXT_P(0);
regex_t *re = (regex_t *) regexp;
int src_text_len = VARSIZE(src_text) - VARHDRSZ;
regex_t *re = (regex_t *) PG_GETARG_POINTER(1);
text *replace_text = PG_GETARG_TEXT_P(2);
bool global = PG_GETARG_BOOL(3);
StringInfo str = makeStringInfo();
int regexec_result;
regmatch_t pmatch[REGEXP_REPLACE_BACKREF_CNT];
@ -2233,14 +2253,18 @@ replace_text_regexp(PG_FUNCTION_ARGS)
break;
/*
* Copy the text when there is a text in the left of matched position.
* Copy the text to the left of the match position. Because we
* are working with character not byte indexes, it's easiest to
* use text_substring to pull out the needed data.
*/
if (pmatch[0].rm_so - data_pos > 0)
{
text *left_text = text_substring(PointerGetDatum(src_text),
data_pos + 1,
pmatch[0].rm_so - data_pos, false);
text *left_text;
left_text = text_substring(PointerGetDatum(src_text),
data_pos + 1,
pmatch[0].rm_so - data_pos,
false);
appendStringInfoText(str, left_text);
pfree(left_text);
}
@ -2259,7 +2283,7 @@ replace_text_regexp(PG_FUNCTION_ARGS)
/*
* When global option is off, replace the first instance only.
*/
if (!global)
if (!glob)
break;
/*
@ -2270,14 +2294,14 @@ replace_text_regexp(PG_FUNCTION_ARGS)
}
/*
* Copy the text when there is a text at the right of last matched or
* regexp is not matched.
* Copy the text to the right of the last match.
*/
if (data_pos < data_len)
{
text *right_text = text_substring(PointerGetDatum(src_text),
data_pos + 1, -1, true);
text *right_text;
right_text = text_substring(PointerGetDatum(src_text),
data_pos + 1, -1, true);
appendStringInfoText(str, right_text);
pfree(right_text);
}
@ -2287,7 +2311,7 @@ replace_text_regexp(PG_FUNCTION_ARGS)
pfree(str);
pfree(data);
PG_RETURN_TEXT_P(ret_text);
return ret_text;
}
/*