Simplify parser.start_with usage.

GitOrigin-RevId: 465e51bba514259ebe15976d2612e1a46754a841

td/telegram/files/FileGenerateManager.cpp

@@ -376,7 +376,7 @@ static Status check_mtime(std::string &conversion, CSlice original_path) {
     return Status::OK();
   }
   ConstParser parser(conversion);
-  if (!parser.skip_start_with("#mtime#")) {
+  if (!parser.try_skip("#mtime#")) {
     return Status::OK();
   }
   auto mtime_str = parser.read_till('#');

tdutils/td/utils/HttpUrl.cpp

@@ -46,8 +46,7 @@ Result<HttpUrl> parse_url(Slice url, HttpUrl::Protocol default_protocol) {
   string protocol_str = to_lower(parser.read_till_nofail(":/?#@[]"));
 
   HttpUrl::Protocol protocol;
-  if (parser.start_with("://")) {
-    parser.advance(3);
+  if (parser.try_skip("://")) {
     if (protocol_str == "http") {
       protocol = HttpUrl::Protocol::Http;
     } else if (protocol_str == "https") {

tdutils/td/utils/JsonBuilder.cpp

@@ -343,17 +343,17 @@ Result<JsonValue> do_json_decode(Parser &parser, int32 max_depth) {
   parser.skip_whitespaces();
   switch (parser.peek_char()) {
     case 'f':
-      if (parser.skip_start_with("false")) {
+      if (parser.try_skip("false")) {
         return JsonValue::create_boolean(false);
       }
       return Status::Error("Token starts with 'f' -- false expected");
     case 't':
-      if (parser.skip_start_with("true")) {
+      if (parser.try_skip("true")) {
         return JsonValue::create_boolean(true);
       }
       return Status::Error("Token starts with 't' -- true expected");
     case 'n':
-      if (parser.skip_start_with("null")) {
+      if (parser.try_skip("null")) {
         return JsonValue();
       }
       return Status::Error("Token starts with 'n' -- null expected");
@@ -463,17 +463,17 @@ Status do_json_skip(Parser &parser, int32 max_depth) {
   parser.skip_whitespaces();
   switch (parser.peek_char()) {
     case 'f':
-      if (parser.skip_start_with("false")) {
+      if (parser.try_skip("false")) {
         return Status::OK();
       }
       return Status::Error("Starts with 'f' -- false expected");
     case 't':
-      if (parser.skip_start_with("true")) {
+      if (parser.try_skip("true")) {
         return Status::OK();
       }
       return Status::Error("Starts with 't' -- true expected");
     case 'n':
-      if (parser.skip_start_with("null")) {
+      if (parser.try_skip("null")) {
         return Status::OK();
       }
       return Status::Error("Starts with 'n' -- null expected");

tdutils/td/utils/Parser.h

@@ -139,6 +139,14 @@ class ParserImpl {
     return false;
   }
 
+  bool try_skip(Slice prefix) {
+    if (prefix.size() > static_cast<size_t>(end_ - ptr_) || prefix != Slice(ptr_, prefix.size())) {
+      return false;
+    }
+    advance(prefix.size());
+    return true;
+  }
+
   void skip_till_not(Slice str) {
     while (ptr_ != end_) {
       if (std::memchr(str.data(), *ptr_, str.size()) == nullptr) {
@@ -163,21 +171,6 @@ class ParserImpl {
     return status_;
   }
 
-  bool start_with(Slice prefix) const {
-    if (prefix.size() > static_cast<size_t>(end_ - ptr_)) {
-      return false;
-    }
-    return prefix == Slice(ptr_, prefix.size());
-  }
-
-  bool skip_start_with(Slice prefix) {
-    if (start_with(prefix)) {
-      advance(prefix.size());
-      return true;
-    }
-    return false;
-  }
-
   void advance(size_t diff) {
     ptr_ += diff;
     CHECK(ptr_ <= end_);