codeview: inline binary annot format and decode helpers

src/codeview/codeview.c

@@ -165,6 +165,74 @@ cv_f64_from_numeric(CV_NumericParsed *num){
   return(result);
 }
 
+////////////////////////////////
+//~ Inline Binary Annotation Helpers
+
+internal U64
+cv_decode_inline_annot_u32(String8 data, U64 offset, U32 *out_value)
+{
+  U32 value;
+
+  U64 cursor = offset;
+
+  U8 header = 0;
+  cursor += str8_deserial_read_struct(data, cursor, &header);
+
+  // 1 byte
+  if((header & 0x80) == 0)
+  {
+    value = header;
+  }
+  // 2 bytes
+  else if((header & 0xC0) == 0x80)
+  {
+    Assert(cursor + sizeof(U8) * 2 <= data.size);
+    U8 second_byte;
+    cursor += str8_deserial_read_struct(data, cursor, &second_byte);
+    value = ((header & 0x3F) << 8) | second_byte;
+  }
+  // 4 bytes
+  else if((header & 0xE0) == 0xC0)
+  {
+    Assert(cursor + sizeof(U8) * 3 <= data.size);
+    U8 second_byte, third_byte, fourth_byte;
+    cursor += str8_deserial_read_struct(data, cursor, &second_byte);
+    cursor += str8_deserial_read_struct(data, cursor, &third_byte);
+    cursor += str8_deserial_read_struct(data, cursor, &fourth_byte);
+    value = (((U32)header & 0x1F) << 24) | ((U32)second_byte << 16) | ((U32)third_byte << 8) | (U32)fourth_byte;
+  }
+  // bad encode
+  else if((header & 0xE0) == 0xE0)
+  {
+    value = max_U32;
+  }
+
+  *out_value = value;
+
+  U64 read_size = cursor - offset;
+  return read_size;
+}
+
+internal U64
+cv_decode_inline_annot_s32(String8 data, U64 offset, S32 *out_value)
+{
+  U32 value;
+
+  U64 read_size = cv_decode_inline_annot_u32(data, offset, &value);
+
+  if(value & 1)
+  {
+    value = -(value >> 1);
+  }
+  else
+  {
+    value = value >> 1;
+  }
+
+  *out_value = (S32)value;
+
+  return read_size;
+}
 
 ////////////////////////////////
 //~ CodeView Sym Parser Functions