start work on webconsole with templates

Signed-off-by: R4SAS <r4sas@i2pmail.org>

libi2pd_webconsole/inja/utils.hpp

@@ -0,0 +1,70 @@
+#ifndef INCLUDE_INJA_UTILS_HPP_
+#define INCLUDE_INJA_UTILS_HPP_
+
+#include <algorithm>
+#include <fstream>
+#include <string>
+#include <string_view>
+#include <utility>
+
+#include "exceptions.hpp"
+
+namespace inja {
+
+namespace string_view {
+inline std::string_view slice(std::string_view view, size_t start, size_t end) {
+  start = std::min(start, view.size());
+  end = std::min(std::max(start, end), view.size());
+  return view.substr(start, end - start);
+}
+
+inline std::pair<std::string_view, std::string_view> split(std::string_view view, char Separator) {
+  size_t idx = view.find(Separator);
+  if (idx == std::string_view::npos) {
+    return std::make_pair(view, std::string_view());
+  }
+  return std::make_pair(slice(view, 0, idx), slice(view, idx + 1, std::string_view::npos));
+}
+
+inline bool starts_with(std::string_view view, std::string_view prefix) {
+  return (view.size() >= prefix.size() && view.compare(0, prefix.size(), prefix) == 0);
+}
+} // namespace string_view
+
+inline SourceLocation get_source_location(std::string_view content, size_t pos) {
+  // Get line and offset position (starts at 1:1)
+  auto sliced = string_view::slice(content, 0, pos);
+  std::size_t last_newline = sliced.rfind("\n");
+
+  if (last_newline == std::string_view::npos) {
+    return {1, sliced.length() + 1};
+  }
+
+  // Count newlines
+  size_t count_lines = 0;
+  size_t search_start = 0;
+  while (search_start <= sliced.size()) {
+    search_start = sliced.find("\n", search_start) + 1;
+    if (search_start == 0) {
+      break;
+    }
+    count_lines += 1;
+  }
+
+  return {count_lines + 1, sliced.length() - last_newline};
+}
+
+inline void replace_substring(std::string& s, const std::string& f, const std::string& t) {
+  if (f.empty()) {
+    return;
+  }
+  for (auto pos = s.find(f);            // find first occurrence of f
+       pos != std::string::npos;        // make sure f was found
+       s.replace(pos, f.size(), t),     // replace with t, and
+       pos = s.find(f, pos + t.size())) // find next occurrence of f
+  {}
+}
+
+} // namespace inja
+
+#endif // INCLUDE_INJA_UTILS_HPP_