signal.c (trap_handler): cleanup to use RSTRING_GETMEM + memcmp

strncmp is unnecessary since the switch/case statement already
checks length of the string; so use memcmp.

This makes for a small reduction in binary size on 32-bit x86:

   text	   data	    bss	    dec	    hex	filename
2847473	  12360	  30632	2890465	 2c1ae1	ruby.before
2847313	  12328	  30632	2890273	 2c1a21	ruby.after

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51287 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 7 deletions

diff --git a/signal.c b/signal.c
index 40caaa660c..5d5cb6b2b6 100644
--- a/signal.c
+++ b/signal.c
@@ -1086,40 +1086,43 @@ trap_handler(VALUE *cmd, int sig)
 	    if (!command) rb_raise(rb_eArgError, "bad handler");
 	}
 	if (!NIL_P(command)) {
+	    const char *cptr;
+	    long len;
 	    SafeStringValue(command);	/* taint check */
 	    *cmd = command;
-	    switch (RSTRING_LEN(command)) {
+	    RSTRING_GETMEM(command, cptr, len);
+	    switch (len) {
 	      case 0:
                 goto sig_ign;
 		break;
               case 14:
-		if (strncmp(RSTRING_PTR(command), "SYSTEM_DEFAULT", 14) == 0) {
+		if (memcmp(cptr, "SYSTEM_DEFAULT", 14) == 0) {
                     func = SIG_DFL;
                     *cmd = 0;
 		}
                 break;
 	      case 7:
-		if (strncmp(RSTRING_PTR(command), "SIG_IGN", 7) == 0) {
+		if (memcmp(cptr, "SIG_IGN", 7) == 0) {
 sig_ign:
                     func = SIG_IGN;
                     *cmd = Qtrue;
 		}
-		else if (strncmp(RSTRING_PTR(command), "SIG_DFL", 7) == 0) {
+		else if (memcmp(cptr, "SIG_DFL", 7) == 0) {
 sig_dfl:
                     func = default_handler(sig);
                     *cmd = 0;
 		}
-		else if (strncmp(RSTRING_PTR(command), "DEFAULT", 7) == 0) {
+		else if (memcmp(cptr, "DEFAULT", 7) == 0) {
                     goto sig_dfl;
 		}
 		break;
 	      case 6:
-		if (strncmp(RSTRING_PTR(command), "IGNORE", 6) == 0) {
+		if (memcmp(cptr, "IGNORE", 6) == 0) {
                     goto sig_ign;
 		}
 		break;
 	      case 4:
-		if (strncmp(RSTRING_PTR(command), "EXIT", 4) == 0) {
+		if (memcmp(cptr, "EXIT", 4) == 0) {
 		    *cmd = Qundef;
 		}
 		break;