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libexpr: Pre-reserve space in string in unescapeStr()

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Avoids some malloc() traffic.
This commit is contained in:
Tuomas Tynkkynen 2018-02-13 01:32:29 +02:00
parent 3a5a241b32
commit f67a7007a2
1 changed files with 4 additions and 3 deletions
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7
src/libexpr/lexer.l
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@ -49,9 +49,10 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
} }
static Expr * unescapeStr(SymbolTable & symbols, const char * s) static Expr * unescapeStr(SymbolTable & symbols, const char * s, size_t length)
{ {
string t; string t;
t.reserve(length);
char c; char c;
while ((c = *s++)) { while ((c = *s++)) {
if (c == '\\') { if (c == '\\') {
@ -150,7 +151,7 @@ or { return OR_KW; }
/* It is impossible to match strings ending with '$' with one /* It is impossible to match strings ending with '$' with one
regex because trailing contexts are only valid at the end regex because trailing contexts are only valid at the end
of a rule. (A sane but undocumented limitation.) */ of a rule. (A sane but undocumented limitation.) */
yylval->e = unescapeStr(data->symbols, yytext); yylval->e = unescapeStr(data->symbols, yytext, yyleng);
return STR; return STR;
} }
<STRING>\$\{ { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; } <STRING>\$\{ { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; }
@ -178,7 +179,7 @@ or { return OR_KW; }
return IND_STR; return IND_STR;
} }
<IND_STRING>\'\'\\. { <IND_STRING>\'\'\\. {
yylval->e = unescapeStr(data->symbols, yytext + 2); yylval->e = unescapeStr(data->symbols, yytext + 2, yyleng - 2);
return IND_STR; return IND_STR;
} }
<IND_STRING>\$\{ { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; } <IND_STRING>\$\{ { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; }