1 files changed, 59 insertions, 0 deletions
diff --git a/src/htmlutil.cc b/src/htmlutil.cc
new file mode 100644
index 0000000..42abc4c
--- /dev/null
+++ b/src/htmlutil.cc
@@ -0,0 +1,59 @@
+#include "common.hh"
+
+#include "htmlutil.hh"
+
+namespace html {
+
+namespace {
+
+constexpr const std::string_view kBodyChars = "&<>";
+constexpr const std::string_view kAttributeChars = "&<>\"'";
+
+}  // namespace
+
+std::string escape(std::string_view in, EscapeTarget target) {
+  std::string out;
+  escape(in, &out, target);
+  return out;
+}
+
+void escape(std::string_view in, std::string* out, EscapeTarget target) {
+  std::string_view chars;
+  switch (target) {
+  case EscapeTarget::BODY:
+    chars = kBodyChars;
+    break;
+  case EscapeTarget::ATTRIBUTE:
+    chars = kAttributeChars;
+    break;
+  }
+  size_t last = 0;
+  while (true) {
+    auto next = in.find_first_of(chars, last);
+    if (next == std::string::npos) {
+      out->append(in, last);
+      break;
+    }
+    out->append(in, last, next - last);
+    switch (in[next]) {
+    case '&':
+      out->append("&amp;");
+      break;
+    case '<':
+      out->append("&lt;");
+      break;
+    case '>':
+      out->append("&gt;");
+      break;
+    case '"':
+      out->append("&quot;");
+      break;
+    case '\'':
+      out->append("&apos;");
+      break;
+    }
+    last = next + 1;
+  }
+}
+
+}  // namespace html