From fe19a47a2ad03a8ae34a044753645dec8dc0b625 Mon Sep 17 00:00:00 2001
From: Reece Wilson <code@reece.sx>
Date: Sat, 13 Aug 2022 06:01:41 +0100
Subject: [PATCH] [+] Missing external class if iterative/codepoint length
 locale apis [+] (internal) UTF8::IterateUTF8

---
 Include/Aurora/Locale/Encoding/Encoding.hpp | 10 +++-
 Source/Locale/Encoding/Encoding.cpp         | 52 +++++++++++++++++++++
 Source/Locale/Encoding/UTFn/AuUTF8.hpp      | 48 +++++++++++++++++++
 3 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/Include/Aurora/Locale/Encoding/Encoding.hpp b/Include/Aurora/Locale/Encoding/Encoding.hpp
index 71d43d97..af38d2b8 100644
--- a/Include/Aurora/Locale/Encoding/Encoding.hpp
+++ b/Include/Aurora/Locale/Encoding/Encoding.hpp
@@ -40,6 +40,14 @@ namespace Aurora::Locale::Encoding
     AUKN_SYM AuUInt32 CountSJISLength   (const Memory::MemoryViewRead &sjis, bool bytes = false); // codepoint = one character
     AUKN_SYM AuUInt32 CountGBK16Length  (const Memory::MemoryViewRead &gbk, bool bytes = false); // codepoint = at most; one GBK byte pair
 
-
     AUKN_SYM AuUInt32 CountEncodedStringLength(ECodePage page, const Memory::MemoryViewRead &view, bool bytes = false);
+    
+    AUKN_SYM AuUInt32 IterateUTF32  (const Memory::MemoryViewRead &utf32);
+    AUKN_SYM AuUInt32 IterateUTF16  (const Memory::MemoryViewRead &utf16);
+    AUKN_SYM AuUInt32 IterateUTF16BE(const Memory::MemoryViewRead &utf16);
+    AUKN_SYM AuUInt32 IterateUTF8   (const Memory::MemoryViewRead &utf8);
+    AUKN_SYM AuUInt32 IterateSJIS   (const Memory::MemoryViewRead &sjis);
+    AUKN_SYM AuUInt32 IterateGBK16  (const Memory::MemoryViewRead &gbk);
+
+    AUKN_SYM AuUInt32 IterateEncodedString(ECodePage page, const Memory::MemoryViewRead &view);
 }
\ No newline at end of file
diff --git a/Source/Locale/Encoding/Encoding.cpp b/Source/Locale/Encoding/Encoding.cpp
index 6f23255e..a0f5f435 100644
--- a/Source/Locale/Encoding/Encoding.cpp
+++ b/Source/Locale/Encoding/Encoding.cpp
@@ -132,4 +132,56 @@ namespace Aurora::Locale::Encoding
             return {};
         }
     }
+
+    AUKN_SYM AuUInt32 IterateUTF32(const Memory::MemoryViewRead &utf32)
+    {
+        return utf32.length < 4 ? 0 : 4;
+    }
+
+    AUKN_SYM AuUInt32 IterateUTF16(const Memory::MemoryViewRead &utf16)
+    {
+        return UTF16::GetLenUC2CodePointLE(utf16.ToPointer(), utf16.length);
+    }
+
+    AUKN_SYM AuUInt32 IterateUTF16BE(const Memory::MemoryViewRead &utf16)
+    {
+        return UTF16::GetLenUC2CodePointBE(utf16.ToPointer(), utf16.length);
+    }
+
+    AUKN_SYM AuUInt32 IterateUTF8(const Memory::MemoryViewRead &utf8)
+    {
+        return UTF8::IterateUTF8(utf8);
+    }
+
+    AUKN_SYM AuUInt32 IterateSJIS(const Memory::MemoryViewRead &sjis)
+    {
+        return SJIS::GetLenSJISCodePoint(sjis.ToPointer(), sjis.length);
+    }
+
+    AUKN_SYM AuUInt32 IterateGBK16(const Memory::MemoryViewRead &gbk)
+    {
+        return GBK::GetLenGBKCodePoint(gbk.ToPointer(), gbk.length);
+    }
+
+    AUKN_SYM AuUInt32 IterateEncodedString(ECodePage page, const Memory::MemoryViewRead &view)
+    {
+        switch (page)
+        {
+        case ECodePage::eGBK:
+            return IterateGBK16(view);
+        case ECodePage::eUTF8:
+            return IterateUTF8(view);
+        case ECodePage::eSJIS:
+            return IterateSJIS(view);
+        case ECodePage::eUTF32:
+        case ECodePage::eUTF32BE:
+            return IterateUTF16(view);
+        case ECodePage::eUTF16:
+            return IterateUTF16(view);
+        case ECodePage::eUTF16BE:
+            return IterateUTF16BE(view);
+        default:
+            return {};
+        }
+    }
 }
\ No newline at end of file
diff --git a/Source/Locale/Encoding/UTFn/AuUTF8.hpp b/Source/Locale/Encoding/UTFn/AuUTF8.hpp
index c97bc636..bf19a491 100644
--- a/Source/Locale/Encoding/UTFn/AuUTF8.hpp
+++ b/Source/Locale/Encoding/UTFn/AuUTF8.hpp
@@ -170,4 +170,52 @@ namespace Aurora::Locale::Encoding::UTF8
         else
             return 0; // I've seen 7 char support in some libs, i thought we should only go up to 6? i haven't seen a coeffient of 0x80000000 x 200h [-1] used in any of them
     }
+
+    static AuUInt32 IterateUTF8(const Memory::MemoryViewRead &utf8)
+    {
+        const char *pItr = utf8.Begin<char>();
+        AuUInt32    nby = 0;
+
+        auto ch = *pItr;
+        unsigned int result = (ch & 0xF0);
+
+        if ((ch & 0x80) == 0)
+        {
+            nby = 1;
+        }
+        else if ((ch & 0xE0) == 0xC0)
+        {
+            nby = 2;
+        }
+        else if (result == 0xE0)
+        {
+            nby = 3;
+        }
+        else if (result == 0xF0)
+        {
+            if ((ch & 0x08) == 0x08)
+            {
+                nby = 5;
+            }
+            else if ((ch & 0x0c) == 0x0c)
+            {
+                nby = 6;
+            }
+            else
+            {
+                nby = 4;
+            }
+        }
+        else
+        {
+            return 0;
+        }
+
+        if (nby > utf8.length)
+        {
+            return 0;
+        }
+
+        return nby;
+    }
 }
\ No newline at end of file