remove micro-optimizations in HTML lexer

This code was attempting to avoid an expensive call to strcasecmp when the first
byte already indicates a mismatch. Modern compilers can perform this
optimization themselves, including inlining strcasecmp and unrolling and
vectorizing its loop. Manually comparing the first byte actually impedes the
compiler because it's harder for it to see your intent. Related to #1913.

diff --git a/lib/common/htmllex.c b/lib/common/htmllex.c
index 8c71cbcb90b84f0d1a40dc8743787e0a531f8e32..a008fa9a032eeb753d8f556e7acf8cf33db71368 100644 (file)
--- a/lib/common/htmllex.c
+++ b/lib/common/htmllex.c
@@ -164,19 +164,11 @@ static int portfn(htmldata_t * p, char *v)
 static int stylefn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c;
     char* tk;
     char* buf = strdup (v);
     for (tk = strtok (buf, DELIM); tk; tk = strtok (NULL, DELIM)) {
-       c = (char) toupper(*tk);
-       if (c == 'R') {
-           if (!strcasecmp(tk + 1, "OUNDED")) p->style |= ROUNDED;
-           else if (!strcasecmp(tk + 1, "ADIAL")) p->style |= RADIAL;
-           else {
-               agerr(AGWARN, "Illegal value %s for STYLE - ignored\n", tk);
-               rv = 1;
-           }
-       }
+       if (!strcasecmp(tk, "ROUNDED")) p->style |= ROUNDED;
+       else if (!strcasecmp(tk, "RADIAL")) p->style |= RADIAL;
        else if(!strcasecmp(tk,"SOLID")) p->style &= ~(DOTTED|DASHED);
        else if(!strcasecmp(tk,"INVISIBLE") || !strcasecmp(tk,"INVIS")) p->style |= INVISIBLE;
        else if(!strcasecmp(tk,"DOTTED")) p->style |= DOTTED;
@@ -307,10 +299,9 @@ static int rowsfn(htmltbl_t * p, char *v)
 static int fixedsizefn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c = (char) toupper(*(unsigned char *) v);
-    if ((c == 'T') && !strcasecmp(v + 1, "RUE"))
+    if (!strcasecmp(v, "TRUE"))
        p->flags |= FIXED_FLAG;
-    else if ((c != 'F') || strcasecmp(v + 1, "ALSE")) {
+    else if (strcasecmp(v, "FALSE")) {
        agerr(AGWARN, "Illegal value %s for FIXEDSIZE - ignored\n", v);
        rv = 1;
     }
@@ -320,12 +311,11 @@ static int fixedsizefn(htmldata_t * p, char *v)
 static int valignfn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c = (char) toupper(*v);
-    if ((c == 'B') && !strcasecmp(v + 1, "OTTOM"))
+    if (!strcasecmp(v, "BOTTOM"))
        p->flags |= VALIGN_BOTTOM;
-    else if ((c == 'T') && !strcasecmp(v + 1, "OP"))
+    else if (!strcasecmp(v, "TOP"))
        p->flags |= VALIGN_TOP;
-    else if ((c != 'M') || strcasecmp(v + 1, "IDDLE")) {
+    else if (strcasecmp(v, "MIDDLE")) {
        agerr(AGWARN, "Illegal value %s for VALIGN - ignored\n", v);
        rv = 1;
     }
@@ -335,12 +325,11 @@ static int valignfn(htmldata_t * p, char *v)
 static int halignfn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c = (char) toupper(*v);
-    if ((c == 'L') && !strcasecmp(v + 1, "EFT"))
+    if (!strcasecmp(v, "LEFT"))
        p->flags |= HALIGN_LEFT;
-    else if ((c == 'R') && !strcasecmp(v + 1, "IGHT"))
+    else if (!strcasecmp(v, "RIGHT"))
        p->flags |= HALIGN_RIGHT;
-    else if ((c != 'C') || strcasecmp(v + 1, "ENTER")) {
+    else if (strcasecmp(v, "CENTER")) {
        agerr(AGWARN, "Illegal value %s for ALIGN - ignored\n", v);
        rv = 1;
     }
@@ -350,14 +339,13 @@ static int halignfn(htmldata_t * p, char *v)
 static int cell_halignfn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c = (char) toupper(*v);
-    if ((c == 'L') && !strcasecmp(v + 1, "EFT"))
+    if (!strcasecmp(v, "LEFT"))
        p->flags |= HALIGN_LEFT;
-    else if ((c == 'R') && !strcasecmp(v + 1, "IGHT"))
+    else if (!strcasecmp(v, "RIGHT"))
        p->flags |= HALIGN_RIGHT;
-    else if ((c == 'T') && !strcasecmp(v + 1, "EXT"))
+    else if (!strcasecmp(v, "TEXT"))
        p->flags |= HALIGN_TEXT;
-    else if ((c != 'C') || strcasecmp(v + 1, "ENTER"))
+    else if (strcasecmp(v, "CENTER"))
        rv = 1;
     if (rv)
        agerr(AGWARN, "Illegal value %s for ALIGN in TD - ignored\n", v);
@@ -367,12 +355,11 @@ static int cell_halignfn(htmldata_t * p, char *v)
 static int balignfn(htmldata_t * p, char *v)
 {
     int rv = 0;
-    char c = (char) toupper(*v);
-    if ((c == 'L') && !strcasecmp(v + 1, "EFT"))
+    if (!strcasecmp(v, "LEFT"))
        p->flags |= BALIGN_LEFT;
-    else if ((c == 'R') && !strcasecmp(v + 1, "IGHT"))
+    else if (!strcasecmp(v, "RIGHT"))
        p->flags |= BALIGN_RIGHT;
-    else if ((c != 'C') || strcasecmp(v + 1, "ENTER"))
+    else if (strcasecmp(v, "CENTER"))
        rv = 1;
     if (rv)
        agerr(AGWARN, "Illegal value %s for BALIGN in TD - ignored\n", v);
@@ -840,7 +827,7 @@ static char *findNext(char *s, agxbuf* xb)
     char c;
 
     if (*s == '<') {
-       if ((*t == '!') && !strncmp(t + 1, "--", 2))
+       if (!strncmp(t, "!--", 3))
            t = eatComment(t + 3);
        else
            while (*t && (*t != '>'))