better utf8 enum

all.h

@@ -351,6 +351,7 @@ typedef struct StringUTF16Const {
 } StringUTF16Const;
 
 typedef enum Utf8Character {
+  Utf8CharacterInvalid = 0,
   Utf8CharacterAscii,
   Utf8CharacterTwoByte,
   Utf8CharacterThreeByte,

string.c

@@ -38,7 +38,7 @@ fn Utf8Character utf8CharacterClassify(u8 c) {
     return Utf8CharacterFourByte;
   } else {
     assert(false && "Not a valid utf8 starting byte");
-    return Utf8Character_Count;
+    return Utf8CharacterInvalid;
   }
 }
 
@@ -55,7 +55,7 @@ fn Utf8Character utf8CharacterClassifyUnsafe(u8 c) {
   } else if (c >= 240) {
     return Utf8CharacterFourByte;
   } else {
-    return Utf8Character_Count;
+    return Utf8CharacterInvalid;
   }
 }
 
@@ -115,29 +115,27 @@ fn bool codepointIsWhitespace(Codepoint c) {
 fn Codepoint codepointFromBytes(ptr bytes, u32 offset) {
   Codepoint result = {0};
   result.type = utf8CharacterClassify(bytes[offset]);
+  result.size = result.type;
   switch (result.type) {
     case Utf8CharacterAscii: {
-      result.size = 1;
       result.code = bytes[offset];
     } break;
     case Utf8CharacterTwoByte: {
-      result.size = 2;
       result.code = (
         bytes[offset] << 8 | bytes[offset+1]
       );
     } break;
     case Utf8CharacterThreeByte: {
-      result.size = 3;
       result.code = (
         bytes[offset] << 16 | bytes[offset+1] << 8 | bytes[offset+2]
       );
     } break;
     case Utf8CharacterFourByte: {
-      result.size = 4;
       result.code = (
         bytes[offset] << 24 | bytes[offset+1] << 16 | bytes[offset+2] << 8 | bytes[offset+3]
       );
     } break;
+    case Utf8CharacterInvalid:
     case Utf8Character_Count: {
       printf("unabled to classify utf8 codepoint %d\n", bytes[offset]);
       assert(false);
@@ -148,36 +146,34 @@ fn Codepoint codepointFromBytes(ptr bytes, u32 offset) {
 
 fn Codepoint codepointFromBytesBefore(ptr bytes, u32 offset) {
   assert(offset > 0);
-  Codepoint result = { .type = Utf8Character_Count };
+  Codepoint result = { .type = Utf8CharacterInvalid };
   u32 i = 0;
-  while (result.type == Utf8Character_Count && i <= 4) {
+  while (result.type == Utf8CharacterInvalid && i <= 4) {
     i++;
     offset -= 1;
     result.type = utf8CharacterClassifyUnsafe(bytes[offset]);
   }
+  result.size = result.type;
   switch (result.type) {
     case Utf8CharacterAscii: {
-      result.size = 1;
       result.code = bytes[offset];
     } break;
     case Utf8CharacterTwoByte: {
-      result.size = 2;
       result.code = (
         bytes[offset] << 8 | bytes[offset+1]
       );
     } break;
     case Utf8CharacterThreeByte: {
-      result.size = 3;
       result.code = (
         bytes[offset] << 16 | bytes[offset+1] << 8 | bytes[offset+2]
       );
     } break;
     case Utf8CharacterFourByte: {
-      result.size = 4;
       result.code = (
         bytes[offset] << 24 | bytes[offset+1] << 16 | bytes[offset+2] << 8 | bytes[offset+3]
       );
     } break;
+    case Utf8CharacterInvalid:
     case Utf8Character_Count: {
       printf("unabled to classify utf8 codepoint %d\n", bytes[offset]);
       assert(false);
@@ -224,6 +220,7 @@ fn void codepointFillBuf(Codepoint cp, ptr buf) {
       buf[2] = (cp.code & 0xFF00) >> 8;
       buf[3] = cp.code & 0xFF;
     } break;
+    case Utf8CharacterInvalid:
     case Utf8Character_Count: {
       assert(false);
     } break;
@@ -233,15 +230,9 @@ fn void codepointFillBuf(Codepoint cp, ptr buf) {
 fn String stringFromRawCodepoint(Arena* a, u32 c) {
   String result = {0};
   Codepoint codepoint = codepointFromRawInt(c);
-  switch (codepoint.type) {
+  assert(codepoint.type != Utf8Character_Count);
-    case Utf8CharacterAscii:      result.capacity = 1; break;
+  assert(codepoint.type != Utf8CharacterInvalid);
-    case Utf8CharacterTwoByte:    result.capacity = 2; break;
+  result.capacity = codepoint.size;
-    case Utf8CharacterThreeByte:  result.capacity = 3; break;
-    case Utf8CharacterFourByte:   result.capacity = 4; break;
-    case Utf8Character_Count: {
-      assert(false);
-    } break;
-  }
   result.length = result.capacity;
   result.bytes = arenaAlloc(a, result.length);
   codepointFillBuf(codepoint, result.bytes);