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Reduce size of backend scanner's tables.

Browse Source 
Previously, the core scanner's yy_transition[] array had 37045 elements.
Since that number is larger than INT16_MAX, Flex generated the array to
contain 32-bit integers.  By reimplementing some of the bulkier scanner
rules, this patch reduces the array to 20495 elements.  The much smaller
total length, combined with the consequent use of 16-bit integers for
the array elements reduces the binary size by over 200kB.  This was
accomplished in two ways:

1. Consolidate handling of quote continuations into a new start condition,
rather than duplicating that logic for five different string types.

2. Treat Unicode strings and identifiers followed by a UESCAPE sequence
as three separate tokens, rather than one.  The logic to de-escape
Unicode strings is moved to the filter code in parser.c, which already
had the ability to provide special processing for token sequences.
While we could have implemented the conversion in the grammar, that
approach was rejected for performance and maintainability reasons.

Performance in microbenchmarks of raw parsing seems equal or slightly
faster in most cases, and it's reasonable to expect that in real-world
usage (with more competition for the CPU cache) there will be a larger
win.  The exception is UESCAPE sequences; lexing those is about 10%
slower, primarily because the scanner now has to be called three times
rather than one.  This seems acceptable since that feature is very
rarely used.

The psql and epcg lexers are likewise modified, primarily because we
want to keep them all in sync.  Since those lexers don't use the
space-hogging -CF option, the space savings is much less, but it's
still good for perhaps 10kB apiece.

While at it, merge the ecpg lexer's handling of C-style comments used
in SQL and in C.  Those have different rules regarding nested comments,
but since we already have the ability to keep track of the previous
start condition, we can use that to handle both cases within a single
start condition.  This matches the core scanner more closely.

John Naylor

Discussion: https://postgr.es/m/CACPNZCvaoa3EgVWm5yZhcSTX6RAtaLgniCPcBVOCwm8h3xpWkw@mail.gmail.com
This commit is contained in:
Tom Lane
2020-01-13 15:04:31 -05:00
parent 259bbe1778
commit 7f380c59f8
19 changed files with 676 additions and 624 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
src/backend/parser/gram.y
View File

@ -598,10 +598,13 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
* the set of keywords. PL/pgSQL depends on this so that it can share the
* same lexer. If you add/change tokens here, fix PL/pgSQL to match!
*
* UIDENT and USCONST are reduced to IDENT and SCONST in parser.c, so that
* they need no productions here; but we must assign token codes to them.
*
* DOT_DOT is unused in the core SQL grammar, and so will always provoke
* parse errors. It is needed by PL/pgSQL.
*/
%token <str> IDENT FCONST SCONST BCONST XCONST Op
%token <str> IDENT UIDENT FCONST SCONST USCONST BCONST XCONST Op
%token <ival> ICONST PARAM
%token TYPECAST DOT_DOT COLON_EQUALS EQUALS_GREATER
%token LESS_EQUALS GREATER_EQUALS NOT_EQUALS
@ -691,8 +694,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
TREAT TRIGGER TRIM TRUE_P
TRUNCATE TRUSTED TYPE_P TYPES_P
UNBOUNDED UNCOMMITTED UNENCRYPTED UNION UNIQUE UNKNOWN UNLISTEN UNLOGGED
UNTIL UPDATE USER USING
UESCAPE UNBOUNDED UNCOMMITTED UNENCRYPTED UNION UNIQUE UNKNOWN
UNLISTEN UNLOGGED UNTIL UPDATE USER USING
VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
VERBOSE VERSION_P VIEW VIEWS VOLATILE
@ -15374,6 +15377,7 @@ unreserved_keyword:
| TRUSTED
| TYPE_P
| TYPES_P
| UESCAPE
| UNBOUNDED
| UNCOMMITTED
| UNENCRYPTED

282
src/backend/parser/parser.c
View File

@ -21,8 +21,14 @@
#include "postgres.h"
#include "mb/pg_wchar.h"
#include "parser/gramparse.h"
#include "parser/parser.h"
#include "parser/scansup.h"
static bool check_uescapechar(unsigned char escape);
static char *str_udeescape(const char *str, char escape,
int position, core_yyscan_t yyscanner);
/*
@ -75,6 +81,10 @@ raw_parser(const char *str)
* scanner backtrack, which would cost more performance than this filter
* layer does.
*
* We also use this filter to convert UIDENT and USCONST sequences into
* plain IDENT and SCONST tokens. While that could be handled by additional
* productions in the main grammar, it's more efficient to do it like this.
*
* The filter also provides a convenient place to translate between
* the core_YYSTYPE and YYSTYPE representations (which are really the
* same thing anyway, but notationally they're different).
@ -104,7 +114,7 @@ base_yylex(YYSTYPE *lvalp, YYLTYPE *llocp, core_yyscan_t yyscanner)
* If this token isn't one that requires lookahead, just return it. If it
* does, determine the token length. (We could get that via strlen(), but
* since we have such a small set of possibilities, hardwiring seems
* feasible and more efficient.)
* feasible and more efficient --- at least for the fixed-length cases.)
*/
switch (cur_token)
{
@ -117,6 +127,10 @@ base_yylex(YYSTYPE *lvalp, YYLTYPE *llocp, core_yyscan_t yyscanner)
case WITH:
cur_token_length = 4;
break;
case UIDENT:
case USCONST:
cur_token_length = strlen(yyextra->core_yy_extra.scanbuf + *llocp);
break;
default:
return cur_token;
}
@ -190,7 +204,273 @@ base_yylex(YYSTYPE *lvalp, YYLTYPE *llocp, core_yyscan_t yyscanner)
break;
}
break;
case UIDENT:
case USCONST:
/* Look ahead for UESCAPE */
if (next_token == UESCAPE)
{
/* Yup, so get third token, which had better be SCONST */
const char *escstr;
/* Again save and restore *llocp */
cur_yylloc = *llocp;
/* Un-truncate current token so errors point to third token */
*(yyextra->lookahead_end) = yyextra->lookahead_hold_char;
/* Get third token */
next_token = core_yylex(&(yyextra->lookahead_yylval),
llocp, yyscanner);
/* If we throw error here, it will point to third token */
if (next_token != SCONST)
scanner_yyerror("UESCAPE must be followed by a simple string literal",
yyscanner);
escstr = yyextra->lookahead_yylval.str;
if (strlen(escstr) != 1 || !check_uescapechar(escstr[0]))
scanner_yyerror("invalid Unicode escape character",
yyscanner);
/* Now restore *llocp; errors will point to first token */
*llocp = cur_yylloc;
/* Apply Unicode conversion */
lvalp->core_yystype.str =
str_udeescape(lvalp->core_yystype.str,
escstr[0],
*llocp,
yyscanner);
/*
* We don't need to revert the un-truncation of UESCAPE. What
* we do want to do is clear have_lookahead, thereby consuming
* all three tokens.
*/
yyextra->have_lookahead = false;
}
else
{
/* No UESCAPE, so convert using default escape character */
lvalp->core_yystype.str =
str_udeescape(lvalp->core_yystype.str,
'\\',
*llocp,
yyscanner);
}
if (cur_token == UIDENT)
{
/* It's an identifier, so truncate as appropriate */
truncate_identifier(lvalp->core_yystype.str,
strlen(lvalp->core_yystype.str),
true);
cur_token = IDENT;
}
else if (cur_token == USCONST)
{
cur_token = SCONST;
}
break;
}
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 in database's encoding? */
static void
check_unicode_value(pg_wchar c, int pos, core_yyscan_t yyscanner)
{
/* See also addunicode() in scan.l */
if (c == 0 || c > 0x10FFFF)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("invalid Unicode escape value"),
scanner_errposition(pos, yyscanner)));
if (c > 0x7F && GetDatabaseEncoding() != PG_UTF8)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8"),
scanner_errposition(pos, yyscanner)));
}
/* is 'escape' acceptable as Unicode escape character (UESCAPE syntax) ? */
static bool
check_uescapechar(unsigned char escape)
{
if (isxdigit(escape)
|| escape == '+'
|| escape == '\''
|| escape == '"'
|| scanner_isspace(escape))
return false;
else
return true;
}
/*
* Process Unicode escapes in "str", producing a palloc'd plain string
*
* escape: the escape character to use
* position: start position of U&'' or U&"" string token
* yyscanner: context information needed for error reports
*/
static char *
str_udeescape(const char *str, char escape,
int position, core_yyscan_t yyscanner)
{
const char *in;
char *new,
*out;
pg_wchar pair_first = 0;
/*
* This relies on the subtle assumption that a UTF-8 expansion cannot be
* longer than its escaped representation.
*/
new = palloc(strlen(str) + 1);
in = str;
out = new;
while (*in)
{
if (in[0] == escape)
{
if (in[1] == escape)
{
if (pair_first)
goto invalid_pair;
*out++ = escape;
in += 2;
}
else if (isxdigit((unsigned char) in[1]) &&
isxdigit((unsigned char) in[2]) &&
isxdigit((unsigned char) in[3]) &&
isxdigit((unsigned char) in[4]))
{
pg_wchar unicode;
unicode = (hexval(in[1]) << 12) +
(hexval(in[2]) << 8) +
(hexval(in[3]) << 4) +
hexval(in[4]);
check_unicode_value(unicode,
in - str + position + 3, /* 3 for U&" */
yyscanner);
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
{
unicode_to_utf8(unicode, (unsigned char *) out);
out += pg_mblen(out);
}
in += 5;
}
else if (in[1] == '+' &&
isxdigit((unsigned char) in[2]) &&
isxdigit((unsigned char) in[3]) &&
isxdigit((unsigned char) in[4]) &&
isxdigit((unsigned char) in[5]) &&
isxdigit((unsigned char) in[6]) &&
isxdigit((unsigned char) in[7]))
{
pg_wchar unicode;
unicode = (hexval(in[2]) << 20) +
(hexval(in[3]) << 16) +
(hexval(in[4]) << 12) +
(hexval(in[5]) << 8) +
(hexval(in[6]) << 4) +
hexval(in[7]);
check_unicode_value(unicode,
in - str + position + 3, /* 3 for U&" */
yyscanner);
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
{
unicode_to_utf8(unicode, (unsigned char *) out);
out += pg_mblen(out);
}
in += 8;
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("invalid Unicode escape value"),
scanner_errposition(in - str + position + 3, /* 3 for U&" */
yyscanner)));
}
else
{
if (pair_first)
goto invalid_pair;
*out++ = *in++;
}
}
/* unfinished surrogate pair? */
if (pair_first)
goto invalid_pair;
*out = '\0';
/*
* We could skip pg_verifymbstr if we didn't process any non-7-bit-ASCII
* codes; but it's probably not worth the trouble, since this isn't likely
* to be a performance-critical path.
*/
pg_verifymbstr(new, out - new, false);
return new;
invalid_pair:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("invalid Unicode surrogate pair"),
scanner_errposition(in - str + position + 3, /* 3 for U&" */
yyscanner)));
return NULL; /* keep compiler quiet */
}

416
src/backend/parser/scan.l
View File

@ -13,8 +13,8 @@
* in the sense that there is always a rule that can match the input
* consumed so far (the rule action may internally throw back some input
* with yyless(), however). As explained in the flex manual, this makes
* for a useful speed increase --- about a third faster than a plain -CF
* lexer, in simple testing. The extra complexity is mostly in the rules
* for a useful speed increase --- several percent faster when measuring
* raw parsing (Flex + Bison). The extra complexity is mostly in the rules
* for handling float numbers and continued string literals. If you change
* the lexical rules, verify that you haven't broken the no-backtrack
* property by running flex with the "-b" option and checking that the
@ -110,14 +110,9 @@ const uint16 ScanKeywordTokens[] = {
static void addlit(char *ytext, int yleng, core_yyscan_t yyscanner);
static void addlitchar(unsigned char ychar, core_yyscan_t yyscanner);
static char *litbufdup(core_yyscan_t yyscanner);
static char *litbuf_udeescape(unsigned char escape, core_yyscan_t yyscanner);
static unsigned char unescape_single_char(unsigned char c, core_yyscan_t yyscanner);
static int process_integer_literal(const char *token, YYSTYPE *lval);
static bool is_utf16_surrogate_first(pg_wchar c);
static bool is_utf16_surrogate_second(pg_wchar c);
static pg_wchar surrogate_pair_to_codepoint(pg_wchar first, pg_wchar second);
static void addunicode(pg_wchar c, yyscan_t yyscanner);
static bool check_uescapechar(unsigned char escape);
#define yyerror(msg) scanner_yyerror(msg, yyscanner)
@ -168,12 +163,11 @@ extern void core_yyset_column(int column_no, yyscan_t yyscanner);
* <xd> delimited identifiers (double-quoted identifiers)
* <xh> hexadecimal numeric string
* <xq> standard quoted strings
* <xqs> quote stop (detect continued strings)
* <xe> extended quoted strings (support backslash escape sequences)
* <xdolq> $foo$ quoted strings
* <xui> quoted identifier with Unicode escapes
* <xuiend> end of a quoted identifier with Unicode escapes, UESCAPE can follow
* <xus> quoted string with Unicode escapes
* <xusend> end of a quoted string with Unicode escapes, UESCAPE can follow
* <xeu> Unicode surrogate pair in extended quoted string
*
* Remember to add an <<EOF>> case whenever you add a new exclusive state!
@ -185,12 +179,11 @@ extern void core_yyset_column(int column_no, yyscan_t yyscanner);
%x xd
%x xh
%x xq
%x xqs
%x xe
%x xdolq
%x xui
%x xuiend
%x xus
%x xusend
%x xeu
/*
@ -231,19 +224,18 @@ special_whitespace ({space}+|{comment}{newline})
horiz_whitespace ({horiz_space}|{comment})
whitespace_with_newline ({horiz_whitespace}*{newline}{special_whitespace}*)
/*
* To ensure that {quotecontinue} can be scanned without having to back up
* if the full pattern isn't matched, we include trailing whitespace in
* {quotestop}. This matches all cases where {quotecontinue} fails to match,
* except for {quote} followed by whitespace and just one "-" (not two,
* which would start a {comment}). To cover that we have {quotefail}.
* The actions for {quotestop} and {quotefail} must throw back characters
* beyond the quote proper.
*/
quote '
quotestop {quote}{whitespace}*
quotecontinue {quote}{whitespace_with_newline}{quote}
quotefail {quote}{whitespace}*"-"
/* If we see {quote} then {quotecontinue}, the quoted string continues */
quotecontinue {whitespace_with_newline}{quote}
/*
* {quotecontinuefail} is needed to avoid lexer backup when we fail to match
* {quotecontinue}. It might seem that this could just be {whitespace}*,
* but if there's a dash after {whitespace_with_newline}, it must be consumed
* to see if there's another dash --- which would start a {comment} and thus
* allow continuation of the {quotecontinue} token.
*/
quotecontinuefail {whitespace}*"-"?
/* Bit string
* It is tempting to scan the string for only those characters
@ -304,21 +296,12 @@ xdstop {dquote}
xddouble {dquote}{dquote}
xdinside [^"]+
/* Unicode escapes */
uescape [uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']{quote}
/* error rule to avoid backup */
uescapefail [uU][eE][sS][cC][aA][pP][eE]{whitespace}*"-"|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*|[uU][eE][sS][cC][aA][pP]|[uU][eE][sS][cC][aA]|[uU][eE][sS][cC]|[uU][eE][sS]|[uU][eE]|[uU]
/* Quoted identifier with Unicode escapes */
xuistart [uU]&{dquote}
/* Quoted string with Unicode escapes */
xusstart [uU]&{quote}
/* Optional UESCAPE after a quoted string or identifier with Unicode escapes. */
xustop1 {uescapefail}?
xustop2 {uescape}
/* error rule to avoid backup */
xufailed [uU]&
@ -476,21 +459,10 @@ other .
startlit();
addlitchar('b', yyscanner);
}
<xb>{quotestop} |
<xb>{quotefail} {
yyless(1);
BEGIN(INITIAL);
yylval->str = litbufdup(yyscanner);
return BCONST;
}
<xh>{xhinside} |
<xb>{xbinside} {
addlit(yytext, yyleng, yyscanner);
}
<xh>{quotecontinue} |
<xb>{quotecontinue} {
/* ignore */
}
<xb><<EOF>> { yyerror("unterminated bit string literal"); }
{xhstart} {
@ -505,13 +477,6 @@ other .
startlit();
addlitchar('x', yyscanner);
}
<xh>{quotestop} |
<xh>{quotefail} {
yyless(1);
BEGIN(INITIAL);
yylval->str = litbufdup(yyscanner);
return XCONST;
}
<xh><<EOF>> { yyerror("unterminated hexadecimal string literal"); }
{xnstart} {
@ -568,53 +533,66 @@ other .
BEGIN(xus);
startlit();
}
<xq,xe>{quotestop} |
<xq,xe>{quotefail} {
yyless(1);
BEGIN(INITIAL);
<xb,xh,xq,xe,xus>{quote} {
/*
* check that the data remains valid if it might have been
* made invalid by unescaping any chars.
* When we are scanning a quoted string and see an end
* quote, we must look ahead for a possible continuation.
* If we don't see one, we know the end quote was in fact
* the end of the string. To reduce the lexer table size,
* we use a single "xqs" state to do the lookahead for all
* types of strings.
*/
if (yyextra->saw_non_ascii)
pg_verifymbstr(yyextra->literalbuf,
yyextra->literallen,
false);
yylval->str = litbufdup(yyscanner);
return SCONST;
yyextra->state_before_str_stop = YYSTATE;
BEGIN(xqs);
}
<xus>{quotestop} |
<xus>{quotefail} {
/* throw back all but the quote */
yyless(1);
/* xusend state looks for possible UESCAPE */
BEGIN(xusend);
<xqs>{quotecontinue} {
/*
* Found a quote continuation, so return to the in-quote
* state and continue scanning the literal. Nothing is
* added to the literal's contents.
*/
BEGIN(yyextra->state_before_str_stop);
}
<xusend>{whitespace} {
/* stay in xusend state over whitespace */
}
<xusend><<EOF>> |
<xusend>{other} |
<xusend>{xustop1} {
/* no UESCAPE after the quote, throw back everything */
<xqs>{quotecontinuefail} |
<xqs>{other} |
<xqs><<EOF>> {
/*
* Failed to see a quote continuation. Throw back
* everything after the end quote, and handle the string
* according to the state we were in previously.
*/
yyless(0);
BEGIN(INITIAL);
yylval->str = litbuf_udeescape('\\', yyscanner);
return SCONST;
}
<xusend>{xustop2} {
/* found UESCAPE after the end quote */
BEGIN(INITIAL);
if (!check_uescapechar(yytext[yyleng - 2]))
switch (yyextra->state_before_str_stop)
{
SET_YYLLOC();
ADVANCE_YYLLOC(yyleng - 2);
yyerror("invalid Unicode escape character");
case xb:
yylval->str = litbufdup(yyscanner);
return BCONST;
case xh:
yylval->str = litbufdup(yyscanner);
return XCONST;
case xq:
case xe:
/*
* Check that the data remains valid, if it might
* have been made invalid by unescaping any chars.
*/
if (yyextra->saw_non_ascii)
pg_verifymbstr(yyextra->literalbuf,
yyextra->literallen,
false);
yylval->str = litbufdup(yyscanner);
return SCONST;
case xus:
yylval->str = litbufdup(yyscanner);
return USCONST;
default:
yyerror("unhandled previous state in xqs");
}
yylval->str = litbuf_udeescape(yytext[yyleng - 2],
yyscanner);
return SCONST;
}
<xq,xe,xus>{xqdouble} {
addlitchar('\'', yyscanner);
}
@ -693,9 +671,6 @@ other .
if (c == '\0' || IS_HIGHBIT_SET(c))
yyextra->saw_non_ascii = true;
}
<xq,xe,xus>{quotecontinue} {
/* ignore */
}
<xe>. {
/* This is only needed for \ just before EOF */
addlitchar(yytext[0], yyscanner);
@ -769,53 +744,13 @@ other .
yylval->str = ident;
return IDENT;
}
<xui>{dquote} {
yyless(1);
/* xuiend state looks for possible UESCAPE */
BEGIN(xuiend);
}
<xuiend>{whitespace} {
/* stay in xuiend state over whitespace */
}
<xuiend><<EOF>> |
<xuiend>{other} |
<xuiend>{xustop1} {
/* no UESCAPE after the quote, throw back everything */
char *ident;
int identlen;
yyless(0);
<xui>{dquote} {
BEGIN(INITIAL);
if (yyextra->literallen == 0)
yyerror("zero-length delimited identifier");
ident = litbuf_udeescape('\\', yyscanner);
identlen = strlen(ident);
if (identlen >= NAMEDATALEN)
truncate_identifier(ident, identlen, true);
yylval->str = ident;
return IDENT;
}
<xuiend>{xustop2} {
/* found UESCAPE after the end quote */
char *ident;
int identlen;
BEGIN(INITIAL);
if (yyextra->literallen == 0)
yyerror("zero-length delimited identifier");
if (!check_uescapechar(yytext[yyleng - 2]))
{
SET_YYLLOC();
ADVANCE_YYLLOC(yyleng - 2);
yyerror("invalid Unicode escape character");
}
ident = litbuf_udeescape(yytext[yyleng - 2], yyscanner);
identlen = strlen(ident);
if (identlen >= NAMEDATALEN)
truncate_identifier(ident, identlen, true);
yylval->str = ident;
return IDENT;
/* can't truncate till after we de-escape the ident */
yylval->str = litbufdup(yyscanner);
return UIDENT;
}
<xd,xui>{xddouble} {
addlitchar('"', yyscanner);
@ -1288,55 +1223,12 @@ process_integer_literal(const char *token, YYSTYPE *lval)
return ICONST;
}
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 */
}
static void
check_unicode_value(pg_wchar c, char *loc, core_yyscan_t yyscanner)
{
if (GetDatabaseEncoding() == PG_UTF8)
return;
if (c > 0x7F)
{
ADVANCE_YYLLOC(loc - yyextra->literalbuf + 3); /* 3 for U&" */
yyerror("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8");
}
}
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 void
addunicode(pg_wchar c, core_yyscan_t yyscanner)
{
char buf[8];
/* See also check_unicode_value() in parser.c */
if (c == 0 || c > 0x10FFFF)
yyerror("invalid Unicode escape value");
if (c > 0x7F)
@ -1349,172 +1241,6 @@ addunicode(pg_wchar c, core_yyscan_t yyscanner)
addlit(buf, pg_mblen(buf), yyscanner);
}
/* is 'escape' acceptable as Unicode escape character (UESCAPE syntax) ? */
static bool
check_uescapechar(unsigned char escape)
{
if (isxdigit(escape)
|| escape == '+'
|| escape == '\''
|| escape == '"'
|| scanner_isspace(escape))
{
return false;
}
else
return true;
}
/* like litbufdup, but handle unicode escapes */
static char *
litbuf_udeescape(unsigned char escape, core_yyscan_t yyscanner)
{
char *new;
char *litbuf,
*in,
*out;
pg_wchar pair_first = 0;
/* Make literalbuf null-terminated to simplify the scanning loop */
litbuf = yyextra->literalbuf;
litbuf[yyextra->literallen] = '\0';
/*
* This relies on the subtle assumption that a UTF-8 expansion cannot be
* longer than its escaped representation.
*/
new = palloc(yyextra->literallen + 1);
in = litbuf;
out = new;
while (*in)
{
if (in[0] == escape)
{
if (in[1] == escape)
{
if (pair_first)
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
*out++ = escape;
in += 2;
}
else if (isxdigit((unsigned char) in[1]) &&
isxdigit((unsigned char) in[2]) &&
isxdigit((unsigned char) in[3]) &&
isxdigit((unsigned char) in[4]))
{
pg_wchar unicode;
unicode = (hexval(in[1]) << 12) +
(hexval(in[2]) << 8) +
(hexval(in[3]) << 4) +
hexval(in[4]);
check_unicode_value(unicode, in, yyscanner);
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");
}
}
else if (is_utf16_surrogate_second(unicode))
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;
}
else if (in[1] == '+' &&
isxdigit((unsigned char) in[2]) &&
isxdigit((unsigned char) in[3]) &&
isxdigit((unsigned char) in[4]) &&
isxdigit((unsigned char) in[5]) &&
isxdigit((unsigned char) in[6]) &&
isxdigit((unsigned char) in[7]))
{
pg_wchar unicode;
unicode = (hexval(in[2]) << 20) +
(hexval(in[3]) << 16) +
(hexval(in[4]) << 12) +
(hexval(in[5]) << 8) +
(hexval(in[6]) << 4) +
hexval(in[7]);
check_unicode_value(unicode, in, yyscanner);
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");
}
}
else if (is_utf16_surrogate_second(unicode))
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;
}
else
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode escape value");
}
}
else
{
if (pair_first)
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
*out++ = *in++;
}
}
/* unfinished surrogate pair? */
if (pair_first)
{
ADVANCE_YYLLOC(in - litbuf + 3); /* 3 for U&" */
yyerror("invalid Unicode surrogate pair");
}
*out = '\0';
/*
* We could skip pg_verifymbstr if we didn't process any non-7-bit-ASCII
* codes; but it's probably not worth the trouble, since this isn't likely
* to be a performance-critical path.
*/
pg_verifymbstr(new, out - new, false);
return new;
}
static unsigned char
unescape_single_char(unsigned char c, core_yyscan_t yyscanner)
{