From 5d6f1f42eec48ae1671e54cdd127f39318416498 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Sun, 10 May 2026 17:54:45 +0100
Subject: Generate renderer functions using TH

These take (and project from) a data type instead of hash maps, _and_
use text-builder-linear, _and_ have the full template inlined. The
result is that this is the fastest renderer yet.
---
 escapexml/EscapeXML.hs | 37 +++++++++++++++++++++++++++++++++++++
 escapexml/escapexml.c  | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 escapexml/EscapeXML.hs
 create mode 100644 escapexml/escapexml.c

(limited to 'escapexml')

diff --git a/escapexml/EscapeXML.hs b/escapexml/EscapeXML.hs
new file mode 100644
index 0000000..662d2ed
--- /dev/null
+++ b/escapexml/EscapeXML.hs
@@ -0,0 +1,37 @@
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE UnboxedTuples #-}
+{-# LANGUAGE UnliftedFFITypes #-}
+module EscapeXML (escapeXML) where
+
+import Data.Array.Byte
+import Data.Text.Internal
+import Foreign.C.Types
+import GHC.Exts
+import GHC.IO (IO(IO))
+import System.IO.Unsafe (unsafePerformIO)
+
+
+foreign import ccall unsafe "tirclogv_escapexml_len"
+  c_escapexml_len :: ByteArray# -> CSize -> CSize -> IO CSize
+
+foreign import ccall unsafe "tirclogv_escapexml"
+  c_escapexml :: MutableByteArray# RealWorld -> ByteArray# -> CSize -> CSize -> IO ()
+
+{-# NOINLINE escapeXML #-}
+escapeXML :: Text -> Text
+escapeXML (Text (ByteArray src#) off len) = unsafePerformIO $ do
+  let offCS = fromIntegral @Int @CSize off
+      lenCS = fromIntegral @Int @CSize len
+
+  reslen <- c_escapexml_len src# offCS lenCS
+  let !reslenI@(I# reslen#) = fromIntegral @CSize @Int reslen
+
+  MutableByteArray dst# <-
+    IO $ \s -> case newByteArray# reslen# s of
+                 (# s', mba# #) -> (# s', MutableByteArray mba# #)
+  c_escapexml dst# src# offCS lenCS
+  ba <- IO $ \s -> case unsafeFreezeByteArray# dst# s of
+                     (# s', ba# #) -> (# s', ByteArray ba# #)
+
+  return (Text ba 0 reslenI)
diff --git a/escapexml/escapexml.c b/escapexml/escapexml.c
new file mode 100644
index 0000000..6eb366d
--- /dev/null
+++ b/escapexml/escapexml.c
@@ -0,0 +1,49 @@
+#include <string.h>
+#include <stdint.h>
+
+// https://hackage-content.haskell.org/package/mustache-2.4.3.1/src/src/Text/Mustache/Internal.hs
+//
+// escapeXML :: String -> String
+// escapeXML = concatMap $ \x -> IntMap.findWithDefault [x] (ord x) mp
+//     where mp = IntMap.fromList [(ord b, "&"++a++";") | (a,[b]) <- xmlEntities]
+//
+// xmlEntities :: [(String, String)]
+// xmlEntities =
+//   [ ("quot", "\"")
+//   , ("#39", "'")
+//   , ("amp" , "&")
+//   , ("lt"  , "<")
+//   , ("gt"  , ">")
+//   ]
+
+#define ENTITIES_XLIST \
+  X('"', 6, "&quot;") \
+  X('\'', 5, "&#39;") \
+  X('&', 5, "&amp;") \
+  X('<', 4, "&lt;") \
+  X('>', 4, "&gt;")
+
+size_t tirclogv_escapexml_len(const uint8_t *src, size_t src_off, size_t src_len) {
+  size_t reslen = 0;
+  for (size_t i = 0; i < src_len; i++) {
+    switch (src[src_off + i]) {
+#define X(ch, len, _str) case ch: reslen += len; break;
+      ENTITIES_XLIST
+#undef X
+      default: reslen += 1; break;
+    }
+  }
+  return reslen;
+}
+
+void tirclogv_escapexml(uint8_t *dst, const uint8_t *src, size_t src_off, size_t src_len) {
+  for (size_t i = 0, j = 0; i < src_len; i++) {
+    const uint8_t c = src[src_off + i];
+    switch (c) {
+#define X(ch, len, str) case ch: memcpy(&dst[j], str, len); j += len; break;
+      ENTITIES_XLIST
+#undef X
+      default: dst[j++] = c; break;
+    }
+  }
+}
-- 
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