From d4f99c8bac8b28f18c864a717d8833db6a1c872d Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Wed, 22 Mar 2023 12:04:33 -0400
Subject: Source map obfuscation  (#2717)

* #include an absolute path didn't work - because paths were taken to always be relative.

* WIP source map.

* Split out handling of RttiTypeFuncs to a map type.

* Make RttiTypeFuncsMap hold default impls.

* Slightly more sophisticated RttiTypeFuncsMap

* Source map decoding.

* Fix tabs.

* Fix asserts due to negative values.

* Use less obscure mechanisms in SourceMap.

* Source map decoding.
Simplifying SourceMap usage.

* First attempt at ouputting a source map as part of emit.

* Added support for -source-map option. SourceMap is added to the artifact.

* Small improvements around column calculation in SourceWriter.

* Source Loc obuscation WIP.

* Fix some issues around SourceMap obfuscation.

* Split out obfuscation into its own file.

* Keep obfuscated SourceMap even through serialization bottleneck.
---
 source/core/slang-char-encode.cpp | 34 ++++++++++++++++++++++++++++++++++
 source/core/slang-char-encode.h   | 10 ++++++++++
 source/core/slang-char-util.h     |  3 +++
 3 files changed, 47 insertions(+)

(limited to 'source/core')

diff --git a/source/core/slang-char-encode.cpp b/source/core/slang-char-encode.cpp
index d061e34ba..687040fa2 100644
--- a/source/core/slang-char-encode.cpp
+++ b/source/core/slang-char-encode.cpp
@@ -178,4 +178,38 @@ CharEncoding* CharEncoding::UTF16 = &_utf16Encoding;
 CharEncoding* CharEncoding::UTF16Reversed = &_utf16EncodingReversed;
 CharEncoding* CharEncoding::UTF32 = &_utf32Encoding;
 	
+/* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! UTF8Util !!!!!!!!!!!!!!!!!!!!!!!!! */
+
+/* static */Index UTF8Util::calcCodePointCount(const UnownedStringSlice& in)
+{
+    Index count = 0;
+
+    // Analyse with bytes...
+    const int8_t* cur = (const int8_t*)in.begin();
+    const int8_t*const end = (const int8_t*)in.end();
+
+    while (cur < end)
+    {
+        const auto c = *cur++;
+        
+        count++;
+
+        // If c < 0 it means the top bit is set... which means we have multiple bytes
+        if (c < 0)
+        {
+            // https://en.wikipedia.org/wiki/UTF-8
+            // All continuation bytes contain exactly six bits from the code point.So the next six bits of the code point 
+            /// are stored in the low order six bits of the next byte, and 10 is stored in the high order two bits to 
+            // mark it as a continuation byte(so 10000010).
+
+            while (cur < end && (*cur & 0xc0) == 0x80)
+            {
+                cur++;
+            }
+        }
+    }
+
+    return count;
+}
+
 } // namespace Slang
diff --git a/source/core/slang-char-encode.h b/source/core/slang-char-encode.h
index a778cc3c9..2bb4cba29 100644
--- a/source/core/slang-char-encode.h
+++ b/source/core/slang-char-encode.h
@@ -195,6 +195,16 @@ protected:
     static CharEncoding*const g_encoding[Index(CharEncodeType::CountOf)];
 };
 
+struct UTF8Util
+{
+        /// Given a slice calculate the number of code points (unicode chars)
+        ///
+        /// NOTE! This doesn't check the *validity* of code points/encoding. 
+        /// Non valid utf8 input or ending starting in partial characters, will produce 
+        /// undefined results without error.
+    static Index calcCodePointCount(const UnownedStringSlice& in);
+};
+
 }
 
 #endif
diff --git a/source/core/slang-char-util.h b/source/core/slang-char-util.h
index 40abee602..1ed8f7f73 100644
--- a/source/core/slang-char-util.h
+++ b/source/core/slang-char-util.h
@@ -47,6 +47,9 @@ struct CharUtil
         /// Given a character return the upper case equivalent
     SLANG_FORCE_INLINE static char toUpper(char c) { return (c >= 'a' && c <= 'z') ? (c -'a' + 'A') : c; }
 
+        /// Given a value between 0-15 inclusive returns the hex digit. Uses lower case hex.
+    SLANG_FORCE_INLINE static char getHexChar(Index i) { SLANG_ASSERT((i & ~Index(0xf)) == 0); return char(i >= 10 ? (i - 10 + 'a') : (i + '0')); }
+
         /// Returns the value if c interpretted as a hex digit
         /// If c is not a valid hex returns -1
     inline static int getHexDigitValue(char c);
-- 
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