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Surrogate pair support for U& string and identifier syntax 

This is mainly to make the functionality consistent with the proposed \u
escape syntax.
This commit is contained in:
Peter Eisentraut 2009-09-21 22:22:07 +00:00
parent c6bc0feb00
commit 02faeb4ac8
2 changed files with 81 additions and 6 deletions
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10
doc/src/sgml/syntax.sgml
View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.134 2009/08/27 20:08:02 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.135 2009/09/21 22:22:07 petere Exp $ -->
<chapter id="sql-syntax">
<title>SQL Syntax</title>
@ -238,6 +238,10 @@ U&amp;"d!0061t!+000061" UESCAPE '!'
The Unicode escape syntax works only when the server encoding is
UTF8. When other server encodings are used, only code points in
the ASCII range (up to <literal>\007F</literal>) can be specified.
Both the 4-digit and the 6-digit form can be used to specify
UTF-16 surrogate pairs to compose characters with code points
larger than <literal>\FFFF</literal> (although the availability of
the 6-digit form technically makes this unnecessary).
</para>
<para>
@ -497,6 +501,10 @@ U&amp;'d!0061t!+000061' UESCAPE '!'
UTF8. When other server encodings are used, only code points in
the ASCII range (up to <literal>\007F</literal>) can be
specified.
Both the 4-digit and the 6-digit form can be used to specify
UTF-16 surrogate pairs to compose characters with code points
larger than <literal>\FFFF</literal> (although the availability
of the 6-digit form technically makes this unnecessary).
</para>
<para>

77
src/backend/parser/scan.l
View File

@ -24,7 +24,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.157 2009/07/14 20:24:10 tgl Exp $
* $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.158 2009/09/21 22:22:07 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -1097,11 +1097,30 @@ check_unicode_value(pg_wchar c, char *loc, base_yyscan_t yyscanner)
}
}
static bool
is_utf16_surrogate_first(pg_wchar c)
{
return (c >= 0xD800 && c <= 0xDBFF);
}
static bool
is_utf16_surrogate_second(pg_wchar c)
{
return (c >= 0xDC00 && c <= 0xDFFF);
}
static pg_wchar
surrogate_pair_to_codepoint(pg_wchar first, pg_wchar second)
{
return ((first & 0x3FF) << 10) + 0x10000 + (second & 0x3FF);
}
static char *
litbuf_udeescape(unsigned char escape, base_yyscan_t yyscanner)
{
char *new;
char *litbuf, *in, *out;
pg_wchar pair_first = 0;
if (isxdigit(escape)
|| escape == '+'
@ -1131,6 +1150,11 @@ litbuf_udeescape(unsigned char escape, base_yyscan_t yyscanner)
{
if (in[1] == escape)
{
if (pair_first)
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
*out++ = escape;
in += 2;
}
@ -1138,9 +1162,27 @@ litbuf_udeescape(unsigned char escape, base_yyscan_t yyscanner)
{
pg_wchar unicode = hexval(in[1]) * 16*16*16 + hexval(in[2]) * 16*16 + hexval(in[3]) * 16 + hexval(in[4]);
check_unicode_value(unicode, in, yyscanner);
unicode_to_utf8(unicode, (unsigned char *) out);
if (pair_first)
{
if (is_utf16_surrogate_second(unicode))
{
unicode = surrogate_pair_to_codepoint(pair_first, unicode);
pair_first = 0;
}
else
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
}
if (is_utf16_surrogate_first(unicode))
pair_first = unicode;
else
{
unicode_to_utf8(unicode, (unsigned char *) out);
out += pg_mblen(out);
}
in += 5;
out += pg_mblen(out);
}
else if (in[1] == '+'
&& isxdigit(in[2]) && isxdigit(in[3])
@ -1150,9 +1192,27 @@ litbuf_udeescape(unsigned char escape, base_yyscan_t yyscanner)
pg_wchar unicode = hexval(in[2]) * 16*16*16*16*16 + hexval(in[3]) * 16*16*16*16 + hexval(in[4]) * 16*16*16
+ hexval(in[5]) * 16*16 + hexval(in[6]) * 16 + hexval(in[7]);
check_unicode_value(unicode, in, yyscanner);
unicode_to_utf8(unicode, (unsigned char *) out);
if (pair_first)
{
if (is_utf16_surrogate_second(unicode))
{
unicode = surrogate_pair_to_codepoint(pair_first, unicode);
pair_first = 0;
}
else
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
}
if (is_utf16_surrogate_first(unicode))
pair_first = unicode;
else
{
unicode_to_utf8(unicode, (unsigned char *) out);
out += pg_mblen(out);
}
in += 8;
out += pg_mblen(out);
}
else
{
@ -1161,7 +1221,14 @@ litbuf_udeescape(unsigned char escape, base_yyscan_t yyscanner)
}
}
else
{
if (pair_first)
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
*out++ = *in++;
}
}
*out = '\0';