Is this way of storing typed objects in memory good?
- by Pindatjuh
This is an "is this okay, or can it be done better" question.
Topic: Storing typed objects in memory.
Background information: I'm building a compiler for the x86-32 platform for my language. My goal includes typed objects.
Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy.
Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries.
The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical possition when going to the right, and check nearest column header for meaning of switch):
Primitive? Array? Type-Meta 1 Byte? || Size (1 byte)
1 1 [...] 1 [...] done
0 2 Bytes? || Size (2 bytes)
1 [...] done
|| Size (4 bytes)
0 [...] done
Integer? 1 Byte? 2 Bytes?
0 1 0 1 done
1 done 0 done
Boolean? Byte?
0 1 0 done
1 done
More-Primitives
0 ....
Class-Stuff (Huge)
0 ...
(After reaching done the data is inserted. || = byte alignement. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.)
For an array of 32 booleans containing all true values, the memory for this type would be (read top-down):
1 Primitive
1 Array
1 ArrayType: Primitive
0 Not-Array
0 Not-Integer
1 Boolean
0 Not-Byte (thus bit)
1 Integer Size: 1 Byte
00100000 Array size
11111111 11111111 11111111 11111111 Data
Thus, 8 bytes represent 32 booleans in an array:
11100101 00100000 11111111 11111111 11111111 11111111
Is this okay, or can it be done better?
