diff options
| -rw-r--r-- | src/libexpr/lexer.l | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l index 70e99d2d2..a0e7a1877 100644 --- a/src/libexpr/lexer.l +++ b/src/libexpr/lexer.l @@ -64,29 +64,32 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len) } -// FIXME: optimize -static Expr * unescapeStr(SymbolTable & symbols, const char * s, size_t length) +// we make use of the fact that the parser receives a private copy of the input +// string and can munge around in it. +static Expr * unescapeStr(SymbolTable & symbols, char * s, size_t length) { - string t; - t.reserve(length); + char * result = s; + char * t = s; char c; + // the input string is terminated with *two* NULs, so we can safely take + // *one* character after the one being checked against. while ((c = *s++)) { if (c == '\\') { - assert(*s); c = *s++; - if (c == 'n') t += '\n'; - else if (c == 'r') t += '\r'; - else if (c == 't') t += '\t'; - else t += c; + if (c == 'n') *t = '\n'; + else if (c == 'r') *t = '\r'; + else if (c == 't') *t = '\t'; + else *t = c; } else if (c == '\r') { /* Normalise CR and CR/LF into LF. */ - t += '\n'; + *t = '\n'; if (*s == '\n') s++; /* cr/lf */ } - else t += c; + else *t = c; + t++; } - return new ExprString(symbols.create(t)); + return new ExprString(symbols.create({result, size_t(t - result)})); } |