scc

Simple C99 Compiler
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commit 606c7f4022fb99a23c906e1d2b23b68f620ca3dd
parent afa1694d36865e5f2d5858e641c573502edaef92
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sat, 18 Jul 2015 09:18:19 +0200

Avoid call to strlen in expand()

We know the size of the expanded string in all the cases,
so it is better to avoid the cll to strlen. We also know that
BUFSIZ is at least 509 bytes, so the calls to snprintf can be
substituted by sprintf

Diffstat:
cc1/cpp.c | 28+++++++++++-----------------
1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/cc1/cpp.c b/cc1/cpp.c @@ -139,10 +139,10 @@ parsepars(char *buffer, char **listp, int nargs) return 1; } -static void -copymacro(char *bp, char *s, size_t bufsiz, char *arglist[]) +static size_t +copymacro(char *buffer, char *s, size_t bufsiz, char *arglist[]) { - char prevc, c, *arg; + char prevc, c, *arg, *bp = buffer; for (prevc = '\0'; c = *s; prevc = c, ++s) { if (c != '@') { @@ -172,7 +172,7 @@ copymacro(char *bp, char *s, size_t bufsiz, char *arglist[]) } *bp = '\0'; - return; + return bp - buffer; expansion_too_long: error("expansion of macro \"%s\" is too long", macroname); @@ -183,22 +183,17 @@ bool expand(char *begin, Symbol *sym) { size_t total, elen, rlen, llen, ilen; - int n, r; + int n; char *s = sym->u.s; char *arglist[NR_MACROARG], arguments[INPUTSIZ], buffer[BUFSIZE]; if (sym == symfile) { - sprintf(buffer, "\"%s\"", input->fname); - goto print_subs; + elen = sprintf(buffer, "\"%s\"", input->fname); + goto substitute; } if (sym == symline) { - r = snprintf(buffer, sizeof(buffer), "%d", input->nline); - if(r == -1 || (size_t)r >= sizeof(buffer)) { - error("expansion of macro \"%s\" is too long", sym->name); - return 0; - } - fprintf(stderr, "Expansion of line '%s'\n", buffer); - goto print_subs; + elen = sprintf(buffer, "%d", input->nline); + goto substitute; } macroname = sym->name; @@ -207,11 +202,10 @@ expand(char *begin, Symbol *sym) for (n = 0; n < atoi(s); ++n) fprintf(stderr, "PAR%d:%s\n", n, arglist[n]); - copymacro(buffer, s+3, INPUTSIZ-1, arglist); + elen = copymacro(buffer, s+3, INPUTSIZ-1, arglist); -print_subs: +substitute: fprintf(stderr, "macro '%s' expanded to :'%s'\n", macroname, buffer); - elen = strlen(buffer); /* expansion lentgh */ rlen = strlen(input->p); /* rigth length */ llen = begin - input->line; /* left length */ ilen = input->p - begin; /* invocation length */