commit 067f761739f4cfa29384dca8b35c532978d0f372
parent 7978a8d8b22b9f9d0e3d5689910be7fb3a4a02fc
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Fri, 15 Jul 2011 09:30:17 -0300
better code for numerical escapes
Diffstat:
M | llex.c | | | 47 | +++++++++++++++++++---------------------------- |
1 file changed, 19 insertions(+), 28 deletions(-)
diff --git a/llex.c b/llex.c
@@ -1,5 +1,5 @@
/*
-** $Id: llex.c,v 2.52 2011/07/08 19:17:30 roberto Exp roberto $
+** $Id: llex.c,v 2.53 2011/07/08 20:01:38 roberto Exp roberto $
** Lexical Analyzer
** See Copyright Notice in lua.h
*/
@@ -297,39 +297,30 @@ static void escerror (LexState *ls, int *c, int n, const char *msg) {
static int readhexaesc (LexState *ls) {
- int c[3]; /* keep input for error message */
- int i = 2; /* at least 'x?' will go to error message */
- c[0] = 'x';
- c[1] = next(ls); /* first hexa digit */
- if (lisxdigit(c[1])) {
- c[i++] = next(ls); /* second hexa digit */
- if (lisxdigit(c[2]))
- return (luaO_hexavalue(c[1]) << 4) + luaO_hexavalue(c[2]);
- /* else go through to error */
+ int c[3], i; /* keep input for error message */
+ int r = 0; /* result accumulator */
+ c[0] = 'x'; /* for error message */
+ for (i = 1; i < 3; i++) { /* read two hexa digits */
+ c[i] = next(ls);
+ if (!lisxdigit(c[i]))
+ escerror(ls, c, i + 1, "hexadecimal digit expected");
+ r = (r << 4) + luaO_hexavalue(c[i]);
}
- escerror(ls, c, i, "hexadecimal digit expected");
- return 0; /* to avoid warnings */
+ return r;
}
static int readdecesc (LexState *ls) {
- int c[3], r;
- int i = 2; /* at least two chars will be read */
- c[0] = ls->current; /* first char must be a digit */
- c[1] = next(ls); /* read second char */
- r = c[0] - '0'; /* partial result */
- if (lisdigit(c[1])) {
- c[i++] = next(ls); /* read third char */
- r = 10*r + c[1] - '0'; /* update result */
- if (lisdigit(c[2])) {
- r = 10*r + c[2] - '0'; /* update result */
- if (r > UCHAR_MAX)
- escerror(ls, c, i, "decimal escape too large");
- return r;
- }
+ int c[3], i;
+ int r = 0; /* result accumulator */
+ for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */
+ c[i] = ls->current;
+ r = 10*r + c[i] - '0';
+ next(ls);
}
- /* else, has read one character that was not a digit */
- zungetc(ls->z); /* return it to input stream */
+ if (r > UCHAR_MAX)
+ escerror(ls, c, i, "decimal escape too large");
+ zungetc(ls->z);
return r;
}