Make minor performance improvement to HTTP parser

redbean's message parser now takes 300 nanoseconds to parse a standard
request sent by chrome, whereas it previous took 600 nanoseconds.

libc/fmt/itoa64radix10.greg.c

@@ -30,8 +30,11 @@ noinline size_t uint64toarray_radix10(uint64_t i, char a[hasatleast 21]) {
   size_t j;
   j = 0;
   do {
-    a[j++] = i % 10 + '0';
-    i /= 10;
+    struct {
+      uint64_t q, r;
+    } x = {i / 10, i % 10};
+    a[j++] = x.r + '0';
+    i = x.q;
   } while (i > 0);
   a[j] = '\0';
   reverse(a, j);

net/http/gethttpheader.inc

@@ -1,6 +1,7 @@
 /* ANSI-C code produced by gperf version 3.1 */
 /* Command-line: gperf gethttpheader.gperf  */
 /* Computed positions: -k'3-4,10' */
+/* clang-format off */
 
 #if !((' ' == 32) && ('!' == 33) && ('"' == 34) && ('#' == 35) \
       && ('%' == 37) && ('&' == 38) && ('\'' == 39) && ('(' == 40) \
@@ -152,7 +153,7 @@ hash (register const char *str, register size_t len)
   return hval;
 }
 
-const struct HttpHeaderSlot *
+static const struct HttpHeaderSlot *
 LookupHttpHeader (register const char *str, register size_t len)
 {
   static const struct HttpHeaderSlot wordlist[] =

net/http/parsehttprequest.c

@@ -42,7 +42,11 @@ void InitHttpRequest(struct HttpRequest *r) {
  * Destroys HTTP request parser.
  */
 void DestroyHttpRequest(struct HttpRequest *r) {
+  if (r->xheaders.p) {
     free(r->xheaders.p);
+    r->xheaders.p = NULL;
+    r->xheaders.n = 0;
+  }
 }
 
 /**
@@ -57,6 +61,8 @@ void DestroyHttpRequest(struct HttpRequest *r) {
  * All other things are permissive to the greatest extent possible.
  * Further functions are provided for the interpretation, validation,
  * and sanitization of various fields.
+ *
+ * @note we assume p points to a buffer that has >=SHRT_MAX bytes
  */
 int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
   int c, h, i;
@@ -72,6 +78,7 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
         r->t = METHOD;
         /* fallthrough */
       case METHOD:
+        for (;;) {
           if (c == ' ') {
             if ((r->method = GetHttpMethod(p + r->a, r->i - r->a)) != -1) {
               r->uri.a = r->i + 1;
@@ -79,9 +86,14 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
             } else {
               return ebadmsg();
             }
+            break;
+          }
+          if (++r->i == n) break;
+          c = p[r->i] & 0xff;
         }
         break;
       case URI:
+        for (;;) {
           if (c == ' ' || c == '\r' || c == '\n') {
             if (r->i == r->uri.a) return ebadmsg();
             r->uri.b = r->i;
@@ -93,6 +105,10 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
             } else {
               r->t = LF1;
             }
+            break;
+          }
+          if (++r->i == n) break;
+          c = p[r->i] & 0xff;
         }
         break;
       case VERSION:
@@ -120,9 +136,14 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
         r->t = HKEY;
         break;
       case HKEY:
+        for (;;) {
           if (c == ':') {
             r->k.b = r->i;
             r->t = HSEP;
+            break;
+          }
+          if (++r->i == n) break;
+          c = p[r->i] & 0xff;
         }
         break;
       case HSEP:
@@ -131,14 +152,16 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
         r->t = HVAL;
         /* fallthrough */
       case HVAL:
+        for (;;) {
           if (c == '\r' || c == '\n') {
             i = r->i;
             while (i > r->a && (p[i - 1] == ' ' || p[i - 1] == '\t')) --i;
             if ((h = GetHttpHeader(p + r->k.a, r->k.b - r->k.a)) != -1) {
               r->headers[h].a = r->a;
               r->headers[h].b = i;
-          } else if ((x = realloc(r->xheaders.p, (r->xheaders.n + 1) *
-                                                     sizeof(*r->xheaders.p)))) {
+            } else if ((x = realloc(
+                            r->xheaders.p,
+                            (r->xheaders.n + 1) * sizeof(*r->xheaders.p)))) {
               x[r->xheaders.n].k = r->k;
               x[r->xheaders.n].v.a = r->a;
               x[r->xheaders.n].v.b = i;
@@ -146,6 +169,10 @@ int ParseHttpRequest(struct HttpRequest *r, const char *p, size_t n) {
               ++r->xheaders.n;
             }
             r->t = c == '\r' ? CR1 : LF1;
+            break;
+          }
+          if (++r->i == n) break;
+          c = p[r->i] & 0xff;
         }
         break;
       case LF2:

test/libc/fmt/itoa64radix10_test.c

@@ -19,6 +19,7 @@
 #include "libc/fmt/conv.h"
 #include "libc/fmt/itoa.h"
 #include "libc/limits.h"
+#include "libc/testlib/ezbench.h"
 #include "libc/testlib/testlib.h"
 
 TEST(int64toarray_radix10, test) {
@@ -64,3 +65,8 @@ TEST(uint128toarray_radix10, test) {
   EXPECT_EQ(39, uint128toarray_radix10(INT128_MIN, buf));
   EXPECT_STREQ("170141183460469231731687303715884105728", buf);
 }
+
+BENCH(itoa64radix10, bench) {
+  char b[21];
+  EZBENCH2("itoa64radix10", donothing, uint64toarray_radix10(UINT64_MAX, b));
+}

test/net/http/parsehttprequest_test.c

@@ -18,10 +18,12 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/bits/bits.h"
 #include "libc/errno.h"
+#include "libc/log/check.h"
 #include "libc/mem/mem.h"
 #include "libc/runtime/gc.internal.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/testlib/ezbench.h"
 #include "libc/testlib/testlib.h"
 #include "libc/x/x.h"
 #include "net/http/http.h"
@@ -199,3 +201,63 @@ User-Agent:  \t hi there \t \r\n\
   EXPECT_EQ(strlen(m), ParseHttpRequest(req, m, strlen(m)));
   EXPECT_STREQ("hi there", gc(slice(m, req->headers[kHttpUserAgent])));
 }
+
+void DoTiniestHttpRequest(void) {
+  static const char m[] = "\
+GET /\r\n\
+\r\n";
+  InitHttpRequest(req);
+  ParseHttpRequest(req, m, sizeof(m));
+  DestroyHttpRequest(req);
+}
+
+void DoTinyHttpRequest(void) {
+  static const char m[] = "\
+GET /\r\n\
+Accept-Encoding: gzip\r\n\
+\r\n";
+  InitHttpRequest(req);
+  ParseHttpRequest(req, m, sizeof(m));
+  DestroyHttpRequest(req);
+}
+
+void DoStandardChromeRequest(void) {
+  static const char m[] = "\
+GET /tool/net/redbean.png HTTP/1.1\r\n\
+Host: 10.10.10.124:8080\r\n\
+Connection: keep-alive\r\n\
+User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36\r\n\
+DNT:  \t1   \r\n\
+Accept: image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8\r\n\
+Referer: http://10.10.10.124:8080/\r\n\
+Accept-Encoding: gzip, deflate\r\n\
+Accept-Language: en-US,en;q=0.9\r\n\
+\r\n";
+  InitHttpRequest(req);
+  CHECK_EQ(sizeof(m) - 1, ParseHttpRequest(req, m, sizeof(m)));
+  DestroyHttpRequest(req);
+}
+
+void DoUnstandardChromeRequest(void) {
+  static const char m[] = "\
+GET /tool/net/redbean.png HTTP/1.1\r\n\
+X-Host: 10.10.10.124:8080\r\n\
+X-Connection: keep-alive\r\n\
+X-User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36\r\n\
+X-DNT:  \t1   \r\n\
+X-Accept: image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8\r\n\
+X-Referer: http://10.10.10.124:8080/\r\n\
+X-Accept-Encoding: gzip, deflate\r\n\
+X-Accept-Language: en-US,en;q=0.9\r\n\
+\r\n";
+  InitHttpRequest(req);
+  CHECK_EQ(sizeof(m) - 1, ParseHttpRequest(req, m, sizeof(m)));
+  DestroyHttpRequest(req);
+}
+
+BENCH(ParseHttpRequest, bench) {
+  EZBENCH2("DoTiniestHttpRequest", donothing, DoTiniestHttpRequest());
+  EZBENCH2("DoTinyHttpRequest", donothing, DoTinyHttpRequest());
+  EZBENCH2("DoStandardChromeRequest", donothing, DoStandardChromeRequest());
+  EZBENCH2("DoUnstandardChromeRequest", donothing, DoUnstandardChromeRequest());
+}

tool/net/redbean.c

@@ -885,24 +885,22 @@ static struct Asset *LocateAssetZip(const char *path, size_t pathlen) {
 }
 
 static struct Asset *LocateAssetFile(const char *path, size_t pathlen) {
+  char *p;
   size_t i;
-  char *path2;
   struct Asset *a;
   if (stagedirs.n) {
     a = FreeLater(xcalloc(1, sizeof(struct Asset)));
     a->file = FreeLater(xmalloc(sizeof(struct File)));
     for (i = 0; i < stagedirs.n; ++i) {
-      if (stat((a->file->path = FreeLater(xasprintf(
+      if (stat((a->file->path = p = FreeLater(xasprintf(
                     "%s%.*s", stagedirs.p[i], request.path.n, request.path.p))),
                &a->file->st) != -1 &&
           (S_ISREG(a->file->st.st_mode) ||
            (S_ISDIR(a->file->st.st_mode) &&
-            ((stat((a->file->path = FreeLater(
-                        xasprintf("%s%s", a->file->path, "index.lua"))),
+            ((stat((a->file->path = FreeLater(xjoinpaths(p, "index.lua"))),
                    &a->file->st) != -1 &&
               S_ISREG(a->file->st.st_mode)) ||
-             (stat((a->file->path = FreeLater(
-                        xasprintf("%s%s", a->file->path, "index.html"))),
+             (stat((a->file->path = FreeLater(xjoinpaths(p, "index.html"))),
                    &a->file->st) != -1 &&
               S_ISREG(a->file->st.st_mode)))))) {
         a->lastmodifiedstr = FormatUnixHttpDateTime(