sh: Optimize variable code by storing the length of the name.
authorPeter Avalos <pavalos@dragonflybsd.org>
Sun, 3 Jul 2011 07:29:43 +0000 (21:29 -1000)
committerPeter Avalos <pavalos@dragonflybsd.org>
Sun, 21 Aug 2011 20:49:02 +0000 (13:49 -0700)
Obtained-from:   FreeBSD SVN rev 221668

bin/sh/var.c
bin/sh/var.h

index 717fd85..6b60b48 100644 (file)
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  * @(#)var.c   8.3 (Berkeley) 5/4/95
- * $FreeBSD: src/bin/sh/var.c,v 1.57 2011/05/06 22:31:27 jilles Exp $
+ * $FreeBSD: src/bin/sh/var.c,v 1.58 2011/05/08 16:15:50 jilles Exp $
  */
 
 #include <unistd.h>
@@ -135,8 +135,8 @@ static const int locale_categories[7] = {
        LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
 };
 
-static struct var **hashvar(const char *);
 static int varequal(const char *, const char *);
+static struct var *find_var(const char *, struct var ***, int *);
 static int localevar(const char *);
 
 /*
@@ -173,20 +173,18 @@ initvar(void)
        struct var **vpp;
 
        for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
-               if ((vp->flags & VEXPORT) == 0) {
-                       vpp = hashvar(ip->text);
-                       vp->next = *vpp;
-                       *vpp = vp;
-                       vp->text = __DECONST(char *, ip->text);
-                       vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
-                       vp->func = ip->func;
-               }
+               if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
+                       continue;
+               vp->next = *vpp;
+               *vpp = vp;
+               vp->text = __DECONST(char *, ip->text);
+               vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
+               vp->func = ip->func;
        }
        /*
         * PS1 depends on uid
         */
-       if ((vps1.flags & VEXPORT) == 0) {
-               vpp = hashvar("PS1=");
+       if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
                vps1.next = *vpp;
                *vpp = &vps1;
                vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
@@ -320,50 +318,46 @@ void
 setvareq(char *s, int flags)
 {
        struct var *vp, **vpp;
-       int len;
+       int nlen;
 
        if (aflag)
                flags |= VEXPORT;
-       vpp = hashvar(s);
-       for (vp = *vpp ; vp ; vp = vp->next) {
-               if (varequal(s, vp->text)) {
-                       if (vp->flags & VREADONLY) {
-                               len = strchr(s, '=') - s;
-                               error("%.*s: is read only", len, s);
-                       }
-                       if (flags & VNOSET)
-                               return;
-                       INTOFF;
-
-                       if (vp->func && (flags & VNOFUNC) == 0)
-                               (*vp->func)(strchr(s, '=') + 1);
-
-                       if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
-                               ckfree(vp->text);
-
-                       vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
-                       vp->flags |= flags;
-                       vp->text = s;
-
-                       /*
-                        * We could roll this to a function, to handle it as
-                        * a regular variable function callback, but why bother?
-                        *
-                        * Note: this assumes iflag is not set to 1 initially.
-                        * As part of init(), this is called before arguments
-                        * are looked at.
-                        */
-                       if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
-                           iflag == 1)
-                               chkmail(1);
-                       if ((vp->flags & VEXPORT) && localevar(s)) {
-                               change_env(s, 1);
-                               setlocale(LC_ALL, "");
-                               updatecharset();
-                       }
-                       INTON;
+       vp = find_var(s, &vpp, &nlen);
+       if (vp != NULL) {
+               if (vp->flags & VREADONLY)
+                       error("%.*s: is read only", vp->name_len, s);
+               if (flags & VNOSET)
                        return;
+               INTOFF;
+
+               if (vp->func && (flags & VNOFUNC) == 0)
+                       (*vp->func)(s + vp->name_len + 1);
+
+               if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+                       ckfree(vp->text);
+
+               vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
+               vp->flags |= flags;
+               vp->text = s;
+
+               /*
+                * We could roll this to a function, to handle it as
+                * a regular variable function callback, but why bother?
+                *
+                * Note: this assumes iflag is not set to 1 initially.
+                * As part of init(), this is called before arguments
+                * are looked at.
+                */
+               if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
+                   iflag == 1)
+                       chkmail(1);
+               if ((vp->flags & VEXPORT) && localevar(s)) {
+                       change_env(s, 1);
+                       setlocale(LC_ALL, "");
+                       updatecharset();
                }
+               INTON;
+               return;
        }
        /* not found */
        if (flags & VNOSET)
@@ -371,6 +365,7 @@ setvareq(char *s, int flags)
        vp = ckmalloc(sizeof (*vp));
        vp->flags = flags;
        vp->text = s;
+       vp->name_len = nlen;
        vp->next = *vpp;
        vp->func = NULL;
        INTOFF;
@@ -412,14 +407,10 @@ lookupvar(const char *name)
 {
        struct var *v;
 
-       for (v = *hashvar(name) ; v ; v = v->next) {
-               if (varequal(v->text, name)) {
-                       if (v->flags & VUNSET)
-                               return NULL;
-                       return strchr(v->text, '=') + 1;
-               }
-       }
-       return NULL;
+       v = find_var(name, NULL, NULL);
+       if (v == NULL || v->flags & VUNSET)
+               return NULL;
+       return v->text + v->name_len + 1;
 }
 
 
@@ -444,15 +435,12 @@ bltinlookup(const char *name, int doall)
        }
        if (result != NULL)
                return result;
-       for (v = *hashvar(name) ; v ; v = v->next) {
-               if (varequal(v->text, name)) {
-                       if ((v->flags & VUNSET)
-                        || (!doall && (v->flags & VEXPORT) == 0))
-                               return NULL;
-                       return strchr(v->text, '=') + 1;
-               }
-       }
-       return NULL;
+
+       v = find_var(name, NULL, NULL);
+       if (v == NULL || v->flags & VUNSET ||
+           (!doall && (v->flags & VEXPORT) == 0))
+               return NULL;
+       return v->text + v->name_len + 1;
 }
 
 
@@ -662,22 +650,18 @@ exportcmd(int argc, char **argv)
                        if ((p = strchr(name, '=')) != NULL) {
                                p++;
                        } else {
-                               vpp = hashvar(name);
-                               for (vp = *vpp ; vp ; vp = vp->next) {
-                                       if (varequal(vp->text, name)) {
-
-                                               vp->flags |= flag;
-                                               if ((vp->flags & VEXPORT) && localevar(vp->text)) {
-                                                       change_env(vp->text, 1);
-                                                       setlocale(LC_ALL, "");
-                                                       updatecharset();
-                                               }
-                                               goto found;
+                               vp = find_var(name, NULL, NULL);
+                               if (vp != NULL) {
+                                       vp->flags |= flag;
+                                       if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+                                               change_env(vp->text, 1);
+                                               setlocale(LC_ALL, "");
+                                               updatecharset();
                                        }
+                                       continue;
                                }
                        }
                        setvar(name, p, flag);
-found:;
                }
        } else {
                for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
@@ -744,8 +728,7 @@ mklocal(char *name)
                memcpy(lvp->text, optlist, sizeof optlist);
                vp = NULL;
        } else {
-               vpp = hashvar(name);
-               for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
+               vp = find_var(name, &vpp, NULL);
                if (vp == NULL) {
                        if (strchr(name, '='))
                                setvareq(savestr(name), VSTRFIXED);
@@ -758,7 +741,7 @@ mklocal(char *name)
                        lvp->text = vp->text;
                        lvp->flags = vp->flags;
                        vp->flags |= VSTRFIXED|VTEXTFIXED;
-                       if (strchr(name, '='))
+                       if (name[vp->name_len] == '=')
                                setvareq(savestr(name), 0);
                }
        }
@@ -854,53 +837,33 @@ unsetvar(const char *s)
        struct var **vpp;
        struct var *vp;
 
-       vpp = hashvar(s);
-       for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
-               if (varequal(vp->text, s)) {
-                       if (vp->flags & VREADONLY)
-                               return (1);
-                       INTOFF;
-                       if (*(strchr(vp->text, '=') + 1) != '\0')
-                               setvar(s, nullstr, 0);
-                       if ((vp->flags & VEXPORT) && localevar(vp->text)) {
-                               change_env(__DECONST(char *, s), 0);
-                               setlocale(LC_ALL, "");
-                               updatecharset();
-                       }
-                       vp->flags &= ~VEXPORT;
-                       vp->flags |= VUNSET;
-                       if ((vp->flags & VSTRFIXED) == 0) {
-                               if ((vp->flags & VTEXTFIXED) == 0)
-                                       ckfree(vp->text);
-                               *vpp = vp->next;
-                               ckfree(vp);
-                       }
-                       INTON;
-                       return (0);
-               }
+       vp = find_var(s, &vpp, NULL);
+       if (vp == NULL)
+               return (0);
+       if (vp->flags & VREADONLY)
+               return (1);
+       INTOFF;
+       if (vp->text[vp->name_len + 1] != '\0')
+               setvar(s, nullstr, 0);
+       if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+               change_env(__DECONST(char *, s), 0);
+               setlocale(LC_ALL, "");
+               updatecharset();
+       }
+       vp->flags &= ~VEXPORT;
+       vp->flags |= VUNSET;
+       if ((vp->flags & VSTRFIXED) == 0) {
+               if ((vp->flags & VTEXTFIXED) == 0)
+                       ckfree(vp->text);
+               *vpp = vp->next;
+               ckfree(vp);
        }
+       INTON;
        return (0);
 }
 
 
 
-/*
- * Find the appropriate entry in the hash table from the name.
- */
-
-static struct var **
-hashvar(const char *p)
-{
-       unsigned int hashval;
-
-       hashval = ((unsigned char) *p) << 4;
-       while (*p && *p != '=')
-               hashval += (unsigned char) *p++;
-       return &vartab[hashval % VTABSIZE];
-}
-
-
-
 /*
  * Returns true if the two strings specify the same varable.  The first
  * variable name is terminated by '='; the second may be terminated by
@@ -918,3 +881,41 @@ varequal(const char *p, const char *q)
                return 1;
        return 0;
 }
+
+/*
+ * Search for a variable.
+ * 'name' may be terminated by '=' or a NUL.
+ * vppp is set to the pointer to vp, or the list head if vp isn't found
+ * lenp is set to the number of charactets in 'name'
+ */
+
+static struct var *
+find_var(const char *name, struct var ***vppp, int *lenp)
+{
+       unsigned int hashval;
+       int len;
+       struct var *vp, **vpp;
+       const char *p = name;
+
+       hashval = 0;
+       while (*p && *p != '=')
+               hashval = 2 * hashval + (unsigned char)*p++;
+       len = p - name;
+
+       if (lenp)
+               *lenp = len;
+       vpp = &vartab[hashval % VTABSIZE];
+       if (vppp)
+               *vppp = vpp;
+
+       for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
+               if (vp->name_len != len)
+                       continue;
+               if (memcmp(vp->text, name, len) != 0)
+                       continue;
+               if (vppp)
+                       *vppp = vpp;
+               return vp;
+       }
+       return NULL;
+}
index 4d62501..b9b4a84 100644 (file)
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *     @(#)var.h       8.2 (Berkeley) 5/4/95
- * $FreeBSD: src/bin/sh/var.h,v 1.20 2011/05/06 22:31:27 jilles Exp $
+ * $FreeBSD: src/bin/sh/var.h,v 1.21 2011/05/08 16:15:50 jilles Exp $
  */
 
 /*
@@ -55,6 +55,7 @@
 struct var {
        struct var *next;               /* next entry in hash list */
        int flags;                      /* flags are defined above */
+       int name_len;                   /* length of name */
        char *text;                     /* name=value */
        void (*func)(const char *);
                                        /* function to be called when  */