feat: improve the performance of `strtolower` functions

src/client/src/tscAsync.c

@@ -347,7 +347,6 @@ bool tscSupportAutoBatch(SSqlObj* pSql) {
   SSqlCmd* pCmd = &pSql->cmd;
   SQueryInfo *pQueryInfo = tscGetQueryInfo(pCmd);
   
-  
   // only support insert statement.
   if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_INSERT)) {
     return false;

src/util/src/tutil.c

@@ -225,66 +225,61 @@ char *tstrstr(char *src, char *dst, bool ignoreInEsc) {
 }
 
 char* strtolower(char *dst, const char *src) {
-  int esc = 0;
-  char quote = 0, *p = dst, c;
-
-  assert(dst != NULL);
-
-  for (c = *src++; c; c = *src++) {
-    if (esc) {
-      esc = 0;
-    } else if (quote) {
-      if (c == '\\') {
-        esc = 1;
-      } else if (c == quote) {
-        quote = 0;
+  if (src == NULL || dst == NULL) {
+    return dst;
+  }
+  char* const ret = dst;
+  while (*src) {
+    char ch = *(src++);
+    ch += (ch >= 'A' && ch <= 'Z') ? 'a' - 'A' : 0;
+    *(dst++) = ch;
+         
+    if (ch == '\'' || ch == '"') {
+      char prev = ch;
+      while (*src) {
+        const char next = *(src++);
+        *(dst++) = next;
+        if (prev != '\\' && next == ch) break;
+        prev = next;
+      }
+    } else if (ch == '`') {
+      while (*src) {
+        const char next = *(src++);
+        *(dst++) = next;
+        if (next == ch) break;
       }
-    } else if (c >= 'A' && c <= 'Z') {
-      c -= 'A' - 'a';
-    } else if (c == '\'' || c == '"') {
-      quote = c;
     }
-    *p++ = c;
   }
-
-  *p = 0;
-  return dst;
+  *(dst) = 0;
+  return ret;
 }
 
 char* strntolower(char *dst, const char *src, int32_t n) {
-  int esc = 0, inEsc = 0;
-  char quote = 0, *p = dst, c;
-
   assert(dst != NULL);
-  if (n == 0) {
-    *p = 0;
-    return dst;
-  }
-  for (c = *src++; n-- > 0; c = *src++) {
-    if (esc) {
-      esc = 0;
-    } else if (quote) {
-      if (c == '\\') {
-        esc = 1;
-      } else if (c == quote) {
-        quote = 0;
+  char* const end = dst + n;
+  while (dst != end) {
+    char ch = *(src++);
+    ch += (ch >= 'A' && ch <= 'Z') ? 'a' - 'A' : 0;
+    *(dst++) = ch;
+         
+    if (ch == '\'' || ch == '"') {
+      char prev = ch;
+      while (dst != end) {
+        const char next = *(src++);
+        *(dst++) = next;
+        if (prev != '\\' && next == ch) break;
+        prev = next;
       }
-    } else if (inEsc) {
-      if (c == '`') {
-        inEsc = 0;
+    } else if (ch == '`') {
+      while (dst != end) {
+        const char next = *(src++);
+        *(dst++) = next;
+        if (next == ch) break;
       }
-    } else if (c >= 'A' && c <= 'Z') {
-      c -= 'A' - 'a';
-    } else if (inEsc == 0 && (c == '\'' || c == '"')) {
-      quote = c;
-    } else if (c == '`' && quote == 0) {
-      inEsc = 1;
     }
-    *p++ = c;
   }
-
-  *p = 0;
-  return dst;
+  *(dst) = 0;
+  return dst - n;
 }
 
 char* strntolower_s(char *dst, const char *src, int32_t n) {