1 files changed, 183 insertions, 0 deletions
diff --git a/libs/tdlib/td/tdutils/td/utils/Parser.h b/libs/tdlib/td/tdutils/td/utils/Parser.h
new file mode 100644
index 0000000000..06e95bf807
--- /dev/null
+++ b/libs/tdlib/td/tdutils/td/utils/Parser.h
@@ -0,0 +1,183 @@
+//
+// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+#pragma once
+
+#include "td/utils/format.h"
+#include "td/utils/logging.h"
+#include "td/utils/Slice.h"
+#include "td/utils/Status.h"
+
+#include <cstring>
+#include <utility>
+
+namespace td {
+
+class Parser {
+ public:
+  explicit Parser(MutableSlice data) : ptr_(data.begin()), end_(data.end()), status_() {
+  }
+  Parser(Parser &&other) : ptr_(other.ptr_), end_(other.end_), status_(std::move(other.status_)) {
+    other.clear();
+  }
+  Parser &operator=(Parser &&other) {
+    if (&other == this) {
+      return *this;
+    }
+    ptr_ = other.ptr_;
+    end_ = other.end_;
+    status_ = std::move(other.status_);
+    other.clear();
+    return *this;
+  }
+  Parser(const Parser &) = delete;
+  Parser &operator=(const Parser &) = delete;
+  ~Parser() = default;
+
+  bool empty() const {
+    return ptr_ == end_;
+  }
+  void clear() {
+    ptr_ = nullptr;
+    end_ = ptr_;
+    status_ = Status::OK();
+  }
+
+  MutableSlice read_till_nofail(char c) {
+    if (status_.is_error()) {
+      return MutableSlice();
+    }
+    char *till = reinterpret_cast<char *>(std::memchr(ptr_, c, end_ - ptr_));
+    if (till == nullptr) {
+      till = end_;
+    }
+    MutableSlice result(ptr_, till);
+    ptr_ = till;
+    return result;
+  }
+
+  MutableSlice read_till_nofail(Slice str) {
+    if (status_.is_error()) {
+      return MutableSlice();
+    }
+    char *best_till = end_;
+    for (auto c : str) {
+      char *till = reinterpret_cast<char *>(std::memchr(ptr_, c, end_ - ptr_));
+      if (till != nullptr && till < best_till) {
+        best_till = till;
+      }
+    }
+    MutableSlice result(ptr_, best_till);
+    ptr_ = best_till;
+    return result;
+  }
+
+  template <class F>
+  MutableSlice read_while(const F &f) {
+    auto save_ptr = ptr_;
+    while (ptr_ != end_ && f(*ptr_)) {
+      ptr_++;
+    }
+    return MutableSlice(save_ptr, ptr_);
+  }
+  MutableSlice read_all() {
+    auto save_ptr = ptr_;
+    ptr_ = end_;
+    return MutableSlice(save_ptr, ptr_);
+  }
+
+  MutableSlice read_till(char c) {
+    if (status_.is_error()) {
+      return MutableSlice();
+    }
+    MutableSlice res = read_till_nofail(c);
+    if (ptr_ == end_ || ptr_[0] != c) {
+      status_ = Status::Error(PSLICE() << "Read till " << tag("char", c) << " failed");
+      return MutableSlice();
+    }
+    return res;
+  }
+
+  char peek_char() {
+    if (ptr_ == end_) {
+      return 0;
+    }
+    return *ptr_;
+  }
+
+  char *ptr() {
+    return ptr_;
+  }
+
+  void skip_nofail(char c) {
+    if (ptr_ != end_ && ptr_[0] == c) {
+      ptr_++;
+    }
+  }
+  void skip(char c) {
+    if (status_.is_error()) {
+      return;
+    }
+    if (ptr_ == end_ || ptr_[0] != c) {
+      status_ = Status::Error(PSLICE() << "Skip " << tag("char", c) << " failed");
+      return;
+    }
+    ptr_++;
+  }
+  bool try_skip(char c) {
+    if (ptr_ != end_ && ptr_[0] == c) {
+      ptr_++;
+      return true;
+    }
+    return false;
+  }
+
+  void skip_till_not(Slice str) {
+    while (ptr_ != end_) {
+      if (std::memchr(str.data(), *ptr_, str.size()) == nullptr) {
+        break;
+      }
+      ptr_++;
+    }
+  }
+  void skip_whitespaces() {
+    skip_till_not(" \t\r\n");
+  }
+
+  MutableSlice data() const {
+    return MutableSlice(ptr_, end_);
+  }
+
+  Status &status() {
+    return status_;
+  }
+
+  bool start_with(Slice prefix) {
+    if (prefix.size() + ptr_ > end_) {
+      return false;
+    }
+    return std::memcmp(prefix.begin(), ptr_, prefix.size()) == 0;
+  }
+
+  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_);
+  }
+
+ private:
+  char *ptr_;
+  char *end_;
+  Status status_;
+};
+}  // namespace td