st 2. 12. 2020 v 11:37 odesílatel Pavel Stehule <[email protected]>
napsal:
>
>
> st 2. 12. 2020 v 9:23 odesílatel Peter Eisentraut <
> [email protected]> napsal:
>
>> On 2020-11-30 22:15, Pavel Stehule wrote:
>> > I would like some supporting documentation on this. So far we only
>> > have
>> > one stackoverflow question, and then this implementation, and they
>> are
>> > not even the same format. My worry is that if there is not precise
>> > specification, then people are going to want to add things in the
>> > future, and there will be no way to analyze such requests in a
>> > principled way.
>> >
>> >
>> > I checked this and it is "prefix backslash-u hex" used by Java,
>> > JavaScript or RTF -
>> > https://billposer.org/Software/ListOfRepresentations.html
>>
>> Heh. The fact that there is a table of two dozen possible
>> representations kind of proves my point that we should be deliberate in
>> picking one.
>>
>> I do see Oracle unistr() on that list, which appears to be very similar
>> to what you are trying to do here. Maybe look into aligning with that.
>>
>
> unistr is a primitive form of proposed function. But it can be used as a
> base. The format is compatible with our "4.1.2.3. String Constants with
> Unicode Escapes".
>
> What do you think about the following proposal?
>
> 1. unistr(text) .. compatible with Postgres unicode escapes - it is
> enhanced against Oracle, because Oracle's unistr doesn't support 6 digits
> unicodes.
>
> 2. there can be optional parameter "prefix" with default "\". But with
> "\u" it can be compatible with Java or Python.
>
> What do you think about it?
>
I thought about it a little bit more, and the prefix specification has not
too much sense (more if we implement this functionality as function
"unistr"). I removed the optional argument and renamed the function to
"unistr". The functionality is the same. Now it supports Oracle convention,
Java and Python (for Python UXXXXXXXX) and \+XXXXXX. These formats was
already supported. The compatibility witth Oracle is nice.
postgres=# select
'Arabic : ' || unistr( '\0627\0644\0639\0631\0628\064A\0629' ) ||
'
Chinese : ' || unistr( '\4E2D\6587' ) ||
'
English : ' || unistr( 'English' ) ||
'
French : ' || unistr( 'Fran\00E7ais' ) ||
'
German : ' || unistr( 'Deutsch' ) ||
'
Greek : ' || unistr( '\0395\03BB\03BB\03B7\03BD\03B9\03BA\03AC' ) ||
'
Hebrew : ' || unistr( '\05E2\05D1\05E8\05D9\05EA' ) ||
'
Japanese : ' || unistr( '\65E5\672C\8A9E' ) ||
'
Korean : ' || unistr( '\D55C\AD6D\C5B4' ) ||
'
Portuguese : ' || unistr( 'Portugu\00EAs' ) ||
'
Russian : ' || unistr( '\0420\0443\0441\0441\043A\0438\0439' ) ||
'
Spanish : ' || unistr( 'Espa\00F1ol' ) ||
'
Thai : ' || unistr( '\0E44\0E17\0E22' )
as unicode_test_string;
┌──────────────────────────┐
│ unicode_test_string │
╞══════════════════════════╡
│ Arabic : العربية ↵│
│ Chinese : 中文 ↵│
│ English : English ↵│
│ French : Français ↵│
│ German : Deutsch ↵│
│ Greek : Ελληνικά ↵│
│ Hebrew : עברית ↵│
│ Japanese : 日本語 ↵│
│ Korean : 한국어 ↵│
│ Portuguese : Português↵│
│ Russian : Русский ↵│
│ Spanish : Español ↵│
│ Thai : ไทย │
└──────────────────────────┘
(1 row)
postgres=# SELECT UNISTR('Odpov\u011Bdn\u00E1 osoba');
┌─────────────────┐
│ unistr │
╞═════════════════╡
│ Odpovědná osoba │
└─────────────────┘
(1 row)
New patch attached
Regards
Pavel
> Pavel
>
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index df29af6371..6ad8136523 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -3553,6 +3553,34 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>unistr</primary>
+ </indexterm>
+ <function>unistr</function> ( <parameter>string</parameter> <type>text</type> )
+ <returnvalue>text</returnvalue>
+ </para>
+ <para>
+ Evaluate escaped unicode chars (4 or 6 digits) without prefix or
+ with prefix <literal>u</literal> (4 digits) or with prefix
+ <literal>U</literal> (8 digits) to chars or with prefix
+ <literal>+</literal> (6 digits).
+ </para>
+ <para>
+ <literal>unistr('\0441\043B\043E\043D')</literal>
+ <returnvalue>слон</returnvalue>
+ </para>
+ <para>
+ <literal>unistr('d\0061t\+000061')</literal>
+ <returnvalue>data</returnvalue>
+ </para>
+ <para>
+ <literal>unistr('d\u0061t\U00000061')</literal>
+ <returnvalue>data</returnvalue>
+ </para></entry>
+ </row>
+
</tbody>
</tgroup>
</table>
diff --git a/src/backend/parser/parser.c b/src/backend/parser/parser.c
index be86eb37fe..cbddb61396 100644
--- a/src/backend/parser/parser.c
+++ b/src/backend/parser/parser.c
@@ -278,30 +278,6 @@ base_yylex(YYSTYPE *lvalp, YYLTYPE *llocp, core_yyscan_t yyscanner)
return cur_token;
}
-/* convert hex digit (caller should have verified that) to value */
-static unsigned int
-hexval(unsigned char c)
-{
- if (c >= '0' && c <= '9')
- return c - '0';
- if (c >= 'a' && c <= 'f')
- return c - 'a' + 0xA;
- if (c >= 'A' && c <= 'F')
- return c - 'A' + 0xA;
- elog(ERROR, "invalid hexadecimal digit");
- return 0; /* not reached */
-}
-
-/* is Unicode code point acceptable? */
-static void
-check_unicode_value(pg_wchar c)
-{
- if (!is_valid_unicode_codepoint(c))
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("invalid Unicode escape value")));
-}
-
/* is 'escape' acceptable as Unicode escape character (UESCAPE syntax) ? */
static bool
check_uescapechar(unsigned char escape)
diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index d07cbafcee..b39dde12bd 100644
--- a/src/backend/parser/scansup.c
+++ b/src/backend/parser/scansup.c
@@ -125,3 +125,27 @@ scanner_isspace(char ch)
return true;
return false;
}
+
+/* convert hex digit (caller should have verified that) to value */
+unsigned int
+hexval(unsigned char c)
+{
+ if (c >= '0' && c <= '9')
+ return c - '0';
+ if (c >= 'a' && c <= 'f')
+ return c - 'a' + 0xA;
+ if (c >= 'A' && c <= 'F')
+ return c - 'A' + 0xA;
+ elog(ERROR, "invalid hexadecimal digit");
+ return 0; /* not reached */
+}
+
+/* is Unicode code point acceptable? */
+void
+check_unicode_value(pg_wchar c)
+{
+ if (!is_valid_unicode_codepoint(c))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("invalid Unicode escape value")));
+}
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index ff9bf238f3..e16f0875d6 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -6290,3 +6290,202 @@ unicode_is_normalized(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(result);
}
+
+/*
+ * First four chars should be hexnum digits
+ */
+static bool
+isxdigit_four(const char *instr)
+{
+ return isxdigit((unsigned char) instr[0]) &&
+ isxdigit((unsigned char) instr[1]) &&
+ isxdigit((unsigned char) instr[2]) &&
+ isxdigit((unsigned char) instr[3]);
+}
+
+/*
+ * Translate string with hexadecimal digits to number
+ */
+static long int
+hexval_four(const char *instr)
+{
+ return (hexval(instr[0]) << 12) +
+ (hexval(instr[1]) << 8) +
+ (hexval(instr[2]) << 4) +
+ hexval(instr[3]);
+}
+
+/*
+ * Replaces unicode escape sequences by unicode chars
+ */
+Datum
+unistr(PG_FUNCTION_ARGS)
+{
+ StringInfoData str;
+ text *input_text;
+ text *result;
+ pg_wchar pair_first = 0;
+ char cbuf[MAX_UNICODE_EQUIVALENT_STRING + 1];
+ char *instr;
+ int len;
+
+ /* when input string is NULL, then result is NULL too */
+ if (PG_ARGISNULL(0))
+ PG_RETURN_NULL();
+
+ input_text = PG_GETARG_TEXT_PP(0);
+ instr = VARDATA_ANY(input_text);
+ len = VARSIZE_ANY_EXHDR(input_text);
+
+ initStringInfo(&str);
+
+ while (len > 0)
+ {
+ if (instr[0] == '\\')
+ {
+ if (len >= 2 &&
+ instr[1] == '\\')
+ {
+ if (pair_first)
+ goto invalid_pair;
+ appendStringInfoChar(&str, '\\');
+ instr += 2;
+ len -= 2;
+ }
+ else if ((len >= 5 && isxdigit_four(&instr[1])) ||
+ (len >= 6 && instr[1] == 'u' && isxdigit_four(&instr[2])))
+ {
+ pg_wchar unicode;
+ int offset = instr[1] == 'u' ? 2 : 1;
+
+ unicode = hexval_four(instr + offset);
+
+ check_unicode_value(unicode);
+
+ if (pair_first)
+ {
+ if (is_utf16_surrogate_second(unicode))
+ {
+ unicode = surrogate_pair_to_codepoint(pair_first, unicode);
+ pair_first = 0;
+ }
+ else
+ goto invalid_pair;
+ }
+ else if (is_utf16_surrogate_second(unicode))
+ goto invalid_pair;
+
+ if (is_utf16_surrogate_first(unicode))
+ pair_first = unicode;
+ else
+ {
+ pg_unicode_to_server(unicode, (unsigned char *) cbuf);
+ appendStringInfoString(&str, cbuf);
+ }
+
+ instr += 4 + offset;
+ len -= 4 + offset;
+ }
+ else if (len >= 8 &&
+ instr[1] == '+' &&
+ isxdigit_four(&instr[2]) &&
+ isxdigit((unsigned char) instr[6]) &&
+ isxdigit((unsigned char) instr[7]))
+ {
+ pg_wchar unicode;
+
+ unicode = (hexval_four(&instr[2]) << 8) +
+ (hexval(instr[6]) << 4) +
+ hexval(instr[7]);
+
+ check_unicode_value(unicode);
+
+ if (pair_first)
+ {
+ if (is_utf16_surrogate_second(unicode))
+ {
+ unicode = surrogate_pair_to_codepoint(pair_first, unicode);
+ pair_first = 0;
+ }
+ else
+ goto invalid_pair;
+ }
+ else if (is_utf16_surrogate_second(unicode))
+ goto invalid_pair;
+
+ if (is_utf16_surrogate_first(unicode))
+ pair_first = unicode;
+ else
+ {
+ pg_unicode_to_server(unicode, (unsigned char *) cbuf);
+ appendStringInfoString(&str, cbuf);
+ }
+
+ instr += 8;
+ len -= 8;
+ }
+ else if (len >= 10 &&
+ instr[1] == 'U' &&
+ isxdigit_four(&instr[2]) &&
+ isxdigit_four(&instr[6]))
+ {
+ pg_wchar unicode;
+
+ unicode = (hexval_four(&instr[2]) << 16) + hexval_four(&instr[6]);
+
+ check_unicode_value(unicode);
+
+ if (pair_first)
+ {
+ if (is_utf16_surrogate_second(unicode))
+ {
+ unicode = surrogate_pair_to_codepoint(pair_first, unicode);
+ pair_first = 0;
+ }
+ else
+ goto invalid_pair;
+ }
+ else if (is_utf16_surrogate_second(unicode))
+ goto invalid_pair;
+
+ if (is_utf16_surrogate_first(unicode))
+ pair_first = unicode;
+ else
+ {
+ pg_unicode_to_server(unicode, (unsigned char *) cbuf);
+ appendStringInfoString(&str, cbuf);
+ }
+
+ instr += 10;
+ len -= 10;
+ }
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("invalid Unicode escape"),
+ errhint("Unicode escapes must be \\XXXX, \\+XXXXXX, \\uXXXX or \\UXXXXXXXX.")));
+ }
+ else
+ {
+ if (pair_first)
+ goto invalid_pair;
+
+ appendStringInfoChar(&str, *instr++);
+ len--;
+ }
+ }
+
+ /* unfinished surrogate pair? */
+ if (pair_first)
+ goto invalid_pair;
+
+ result = cstring_to_text_with_len(str.data, str.len);
+ pfree(str.data);
+
+ PG_RETURN_TEXT_P(result);
+
+invalid_pair:
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("invalid Unicode surrogate pair")));
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fc2202b843..92149b9cc2 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -11010,4 +11010,7 @@
proname => 'is_normalized', prorettype => 'bool', proargtypes => 'text text',
prosrc => 'unicode_is_normalized' },
+{ oid => '9822', descr => 'unescape Unicode chars in strings',
+ proname => 'unistr', prorettype => 'text', proargtypes => 'text',
+ proisstrict => 't', prosrc => 'unistr' }
]
diff --git a/src/include/parser/scansup.h b/src/include/parser/scansup.h
index 5bc426660d..1481c1da01 100644
--- a/src/include/parser/scansup.h
+++ b/src/include/parser/scansup.h
@@ -14,6 +14,8 @@
#ifndef SCANSUP_H
#define SCANSUP_H
+#include "mb/pg_wchar.h"
+
extern char *downcase_truncate_identifier(const char *ident, int len,
bool warn);
@@ -24,4 +26,8 @@ extern void truncate_identifier(char *ident, int len, bool warn);
extern bool scanner_isspace(char ch);
+extern unsigned int hexval(unsigned char c);
+
+extern void check_unicode_value(pg_wchar c);
+
#endif /* SCANSUP_H */
diff --git a/src/test/regress/expected/unicode.out b/src/test/regress/expected/unicode.out
index 2a1e903696..778ef6e696 100644
--- a/src/test/regress/expected/unicode.out
+++ b/src/test/regress/expected/unicode.out
@@ -79,3 +79,30 @@ ORDER BY num;
SELECT is_normalized('abc', 'def'); -- run-time error
ERROR: invalid normalization form: def
+SELECT unistr('\0441\043B\043E\043D');
+ unistr
+--------
+ слон
+(1 row)
+
+SELECT unistr('d\u0061t\U00000061');
+ unistr
+--------
+ data
+(1 row)
+
+-- run-time error
+SELECT unistr('wrong: \db99');
+ERROR: invalid Unicode surrogate pair
+SELECT unistr('wrong: \db99\0061');
+ERROR: invalid Unicode surrogate pair
+SELECT unistr('wrong: \+00db99\+000061');
+ERROR: invalid Unicode surrogate pair
+SELECT unistr('wrong: \+2FFFFF');
+ERROR: invalid Unicode escape value
+SELECT unistr('wrong: \udb99\u0061');
+ERROR: invalid Unicode surrogate pair
+SELECT unistr('wrong: \U0000db99\U00000061');
+ERROR: invalid Unicode surrogate pair
+SELECT unistr('wrong: \U002FFFFF');
+ERROR: invalid Unicode escape value
diff --git a/src/test/regress/sql/unicode.sql b/src/test/regress/sql/unicode.sql
index ccfc6fa77a..546e85f8cd 100644
--- a/src/test/regress/sql/unicode.sql
+++ b/src/test/regress/sql/unicode.sql
@@ -30,3 +30,15 @@ FROM
ORDER BY num;
SELECT is_normalized('abc', 'def'); -- run-time error
+
+SELECT unistr('\0441\043B\043E\043D');
+SELECT unistr('d\u0061t\U00000061');
+
+-- run-time error
+SELECT unistr('wrong: \db99');
+SELECT unistr('wrong: \db99\0061');
+SELECT unistr('wrong: \+00db99\+000061');
+SELECT unistr('wrong: \+2FFFFF');
+SELECT unistr('wrong: \udb99\u0061');
+SELECT unistr('wrong: \U0000db99\U00000061');
+SELECT unistr('wrong: \U002FFFFF');
