[core] light_isupper(), light_islower()

more efficient char checks
(replace one comparision and one branch with one subtraction)

src/array.c

@@ -101,8 +101,8 @@ static int array_caseless_compare(const char * const a, const char * const b, co
         if (ca == cb) continue;
 
         /* always lowercase for transitive results */
-        if (ca >= 'A' && ca <= 'Z') ca |= 32;
-        if (cb >= 'A' && cb <= 'Z') cb |= 32;
+        if (light_isupper(ca)) ca |= 0x20;
+        if (light_isupper(cb)) cb |= 0x20;
 
         if (ca == cb) continue;
         return (int)(ca - cb);

src/buffer.c

@@ -327,9 +327,9 @@ int buffer_eq_icase_ssn(const char * const a, const char * const b, const size_t
         if (ca != cb) {
             ca |= 0x20;
             cb |= 0x20;
-            if (ca       !=       cb) return 0;
-            if (ca < 'a' || 'z' < ca) return 0;
-            if (cb < 'a' || 'z' < cb) return 0;
+            if (ca != cb) return 0;
+            if (!light_islower(ca)) return 0;
+            if (!light_islower(cb)) return 0;
         }
     }
     return 1;
@@ -921,19 +921,17 @@ void buffer_path_simplify(buffer *dest, buffer *src)
 }
 
 void buffer_to_lower(buffer * const b) {
-    char * const s = b->ptr;
+    unsigned char * const restrict s = (unsigned char *)b->ptr;
     for (uint32_t i = 0; i < b->used; ++i) {
-        char c = s[i];
-        if (c >= 'A' && c <= 'Z') s[i] |= 0x20;
+        if (light_isupper(s[i])) s[i] |= 0x20;
     }
 }
 
 
 void buffer_to_upper(buffer * const b) {
-    char * const s = b->ptr;
+    unsigned char * const restrict s = (unsigned char *)b->ptr;
     for (uint32_t i = 0; i < b->used; ++i) {
-        char c = s[i];
-        if (c >= 'a' && c <= 'z') s[i] &= ~0x20;
+        if (light_islower(s[i])) s[i] &= 0xdf;
     }
 }
 

src/buffer.h

@@ -193,19 +193,19 @@ char int2hex(char i);
 __attribute_pure__
 static inline int light_isdigit(int c);
 static inline int light_isdigit(int c) {
-	return (c >= '0' && c <= '9');
+	return ((uint32_t)c-'0' <= '9'-'0');
 }
 
 __attribute_pure__
 static inline int light_isxdigit(int c);
 static inline int light_isxdigit(int c) {
-	return light_isdigit(c) || (c |= 32, c >= 'a' && c <= 'f');
+	return light_isdigit(c) || (((uint32_t)c | 0x20)-'a' <= 'f'-'a');
 }
 
 __attribute_pure__
 static inline int light_isalpha(int c);
 static inline int light_isalpha(int c) {
-	return (c |= 32, c >= 'a' && c <= 'z');
+	return (((uint32_t)c | 0x20)-'a' <= 'z'-'a');
 }
 
 __attribute_pure__
@@ -214,6 +214,9 @@ static inline int light_isalnum(int c) {
 	return light_isdigit(c) || light_isalpha(c);
 }
 
+#define light_isupper(c) ((uint32_t)(c)-'A' <= 'Z'-'A')
+#define light_islower(c) ((uint32_t)(c)-'a' <= 'z'-'a')
+
 
 __attribute_pure__
 static inline uint32_t buffer_string_length(const buffer *b); /* buffer string length without terminating 0 */

src/burl.c

@@ -463,7 +463,7 @@ static void burl_offset_tolower (buffer * const b, const size_t off)
 {
     /*(skips over all percent-encodings, including encoding of alpha chars)*/
     for (char *p = b->ptr+off; p[0]; ++p) {
-        if (p[0] >= 'A' && p[0] <= 'Z') p[0] |= 0x20;
+        if (light_isupper(p[0])) p[0] |= 0x20;
         else if (p[0]=='%' && light_isxdigit(p[1]) && light_isxdigit(p[2]))
             p+=2;
     }
@@ -474,7 +474,7 @@ static void burl_offset_toupper (buffer * const b, const size_t off)
 {
     /*(skips over all percent-encodings, including encoding of alpha chars)*/
     for (char *p = b->ptr+off; p[0]; ++p) {
-        if (p[0] >= 'a' && p[0] <= 'z') p[0] &= 0xdf;
+        if (light_islower(p[0])) p[0] &= 0xdf;
         else if (p[0]=='%' && light_isxdigit(p[1]) && light_isxdigit(p[2]))
             p+=2;
     }

src/h2.c

@@ -1644,7 +1644,7 @@ h2_send_headers (request_st * const r, connection * const con)
          * end of value buffer */
         char * const v = buffer_string_prepare_append(&ds->value, klen);
         for (uint32_t j = 0; j < klen; ++j)
-            v[j] = (k[j] < 'A' || k[j] > 'Z') ? k[j] : (k[j] | 0x20);
+            v[j] = !light_isupper(k[j]) ? k[j] : (k[j] | 0x20);
         /*buffer_commit(&ds->value, klen);*//*(not necessary; truncated below)*/
 
         uint32_t voff = 0;
@@ -1908,7 +1908,7 @@ h2_send_end_stream_trailers (request_st * const r, connection * const con, const
         const char * const colon = memchr(k, ':', ptr+hoff[i+1]-k);
         if (NULL == colon) continue;
         do {
-            if (*k >= 'A' && *k <= 'Z') *k |= 0x20;
+            if (light_isupper(*k)) *k |= 0x20;
         } while (++k != colon);
     }
 

src/http_auth.c

@@ -192,10 +192,10 @@ int http_auth_digest_hex2bin (const char *hexstr, size_t len, unsigned char *bin
         int hi = hexstr[i];
         int lo = hexstr[i+1];
         if ('0' <= hi && hi <= '9')                    hi -= '0';
-        else if ((hi |= 0x20), 'a' <= hi && hi <= 'f') hi += -'a' + 10;
+        else if ((uint32_t)(hi |= 0x20)-'a' <= 'f'-'a')hi += -'a' + 10;
         else                                           return -1;
         if ('0' <= lo && lo <= '9')                    lo -= '0';
-        else if ((lo |= 0x20), 'a' <= lo && lo <= 'f') lo += -'a' + 10;
+        else if ((uint32_t)(lo |= 0x20)-'a' <= 'f'-'a')lo += -'a' + 10;
         else                                           return -1;
         bin[(i >> 1)] = (unsigned char)((hi << 4) | lo);
     }
@@ -209,9 +209,9 @@ int http_auth_md5_hex2lc (char *md5hex)
     int i;
     for (i = 0; md5hex[i]; ++i) {
         int c = md5hex[i];
-        if ('0' <= c && c <= '9')                   continue;
-        else if ((c |= 0x20), 'a' <= c && c <= 'f') md5hex[i] = c;
-        else                                        return -1;
+        if ('0' <= c && c <= '9')                      continue;
+        else if ((uint32_t)(c |= 0x20)-'a' <= 'f'-'a') md5hex[i] = c;
+        else                                           return -1;
     }
     return (32 == i) ? 0 : -1; /*(Note: char *md5hex must be a 32-char string)*/
 }

src/http_header.c

@@ -195,7 +195,7 @@ void http_header_response_insert(request_st * const r, enum http_header_e id, co
             r->resp_header_repeated = 1;
             char * const h = buffer_string_prepare_append(vb, klen + vlen + 2);
             for (uint32_t i = 0; i < klen; ++i)
-                h[i] = (k[i] < 'A' || k[i] > 'Z') ? k[i] : (k[i] | 0x20);
+                h[i] = !light_isupper(k[i]) ? k[i] : (k[i] | 0x20);
             buffer_commit(vb, klen);
         }
         else

src/mod_secdownload.c

@@ -477,12 +477,8 @@ static int is_hex_len(const char *str, size_t len) {
 
 	for (i = 0; i < len && *str; i++, str++) {
 		/* illegal characters */
-		if (!((*str >= '0' && *str <= '9') ||
-		      (*str >= 'a' && *str <= 'f') ||
-		      (*str >= 'A' && *str <= 'F'))
-		    ) {
+		if (!light_isxdigit(*str))
 			return 0;
-		}
 	}
 
 	return i == len;
@@ -502,13 +498,8 @@ static int is_base64_len(const char *str, size_t len) {
 
 	for (i = 0; i < len && *str; i++, str++) {
 		/* illegal characters */
-		if (!((*str >= '0' && *str <= '9') ||
-		      (*str >= 'a' && *str <= 'z') ||
-		      (*str >= 'A' && *str <= 'Z') ||
-		      (*str == '-') || (*str == '_'))
-		    ) {
+		if (!(light_isalnum(*str) || *str == '-' || *str == '_'))
 			return 0;
-		}
 	}
 
 	return i == len;

src/mod_userdir.c

@@ -179,7 +179,7 @@ static handler_t mod_userdir_docroot_construct(request_st * const r, plugin_data
 
         if (r->conf.force_lowercase_filenames) {
             for (size_t i = 0; i < ulen; ++i) {
-                if (u[i] >= 'A' && u[i] <= 'Z') u[i] |= 0x20;
+                if (light_isupper(u[i])) u[i] |= 0x20;
             }
         }
 

src/request.c

@@ -784,9 +784,9 @@ http_request_parse_header (request_st * const restrict r, http_header_parse_ctx
               (hpctx->http_parseopts & HTTP_PARSEOPT_HEADER_STRICT);
 
             for (uint32_t j = 0; j < klen; ++j) {
-                if ((k[j] >= 'a' && k[j] <= 'z') || k[j] == '-')
+                if (light_islower(k[j]) || k[j] == '-')
                     continue; /*(common cases)*/
-                if (k[j] >= 'A' && k[j] <= 'Z')
+                if (light_isupper(k[j]))
                     return 400;
                 if (0 != http_request_parse_header_other(r, k+j, klen-j,
                                                          http_header_strict))