faster escape

2% int'ов сидят в Escape. pepe watafa.
<https://nda.ya.ru/t/AJC4zGq27VFEkb>

Тут играясь с блоками получилось на реальном cgi из прода \~33% срезать. Мелочь, а приятно. На самом деле, хотелось бы узнать как правильно делать "некрасивую, но ускоряющую" гадость в library/cpp. Все тесты работают, но тем не менее =)

До: <https://nda.ya.ru/t/Iv6Y0jQf7VFEkc>

После: <https://nda.ya.ru/t/KO_Rgvi87VFEke>

Тут, к сожалению не на прогрузе, но уже видно.
commit_hash:671028887e7d9320c8e9a393a0abb203207eb883

1 files changed, 52 insertions, 13 deletions

diff --git a/library/cpp/string_utils/quote/quote.cpp b/library/cpp/string_utils/quote/quote.cpp
index 9559132ae6f..91e31da1102 100644
--- a/library/cpp/string_utils/quote/quote.cpp
+++ b/library/cpp/string_utils/quote/quote.cpp
@@ -62,10 +62,6 @@ namespace {
     };
 }
 
-static inline char d2x(unsigned x) {
-    return (char)((x < 10) ? ('0' + x) : ('A' + x - 10));
-}
-
 static inline const char* FixZero(const char* s) noexcept {
     return s ? s : "";
 }
@@ -101,22 +97,65 @@ static const bool chars_to_url_escape[256] = {
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, //F
 };
 
+static const char d2x[16] = {
+    '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
+};
+
+template <class It1>
+static inline void EscapeHelper(It1& to, unsigned char c, const bool* escape_map) {
+    if (!escape_map[c]) {
+        *to++ = (c == ' ') ? '+' : c;
+    } else {
+        *to++ = '%';
+        *to++ = d2x[c >> 4];
+        *to++ = d2x[c & 0xF];
+    }
+}
+
 template <class It1, class It2, class It3>
 static inline It1 Escape(It1 to, It2 from, It3 end, const bool* escape_map = chars_to_url_escape) {
     while (from != end) {
-        if (escape_map[(unsigned char)*from]) {
-            *to++ = '%';
-            *to++ = d2x((unsigned char)*from >> 4);
-            *to++ = d2x((unsigned char)*from & 0xF);
+        EscapeHelper(to, *from++, escape_map);
+    }
+
+    *to = 0;
+
+    return to;
+}
+
+static inline char* Escape(char* to, const char* from, const char* end, const bool* escape_map = chars_to_url_escape) {
+    constexpr size_t BLOCK = 16;
+
+    while (from + BLOCK <= end) {
+        uint32_t escape_count = 0;
+        for (size_t i = 0; i < BLOCK; ++i) {
+            escape_count |= escape_map[(unsigned char)from[i]];
+        }
+
+        if (escape_count == 0) {
+            unsigned char src[BLOCK];
+            for (size_t i = 0; i < BLOCK; ++i) {
+                src[i] = from[i];
+            }
+            for (size_t i = 0; i < BLOCK; ++i) {
+                unsigned char c = src[i];
+                to[i] = (c == ' ') ? '+' : c;
+            }
+            to += BLOCK;
         } else {
-            *to++ = (*from == ' ' ? '+' : *from);
+            for (size_t i = 0; i < BLOCK; ++i) {
+                unsigned char c = from[i];
+                EscapeHelper(to, c, escape_map);
+            }
         }
+        from += BLOCK;
+    }
 
-        ++from;
+    while (from != end) {
+        EscapeHelper(to, *from++, escape_map);
     }
 
     *to = 0;
-
     return to;
 }
 
@@ -282,8 +321,8 @@ char* UrlEscape(char* to, TStringBuf src, bool forceEscape) {
 
         if (escapePercent || (unsigned char)*from <= ' ' || (unsigned char)*from > '~') {
             *to++ = '%';
-            *to++ = d2x((unsigned char)*from >> 4);
-            *to++ = d2x((unsigned char)*from & 0xF);
+            *to++ = d2x[(unsigned char)*from >> 4];
+            *to++ = d2x[(unsigned char)*from & 0xF];
         } else
             *to++ = *from;
     }