When in TU_CS_MODE_SUB_STREAM, tu_cs_begin_sub_stream (or
tu_cs_end_sub_stream) should be called instead of tu_cs_begin (or
tu_cs_end). It gives the caller a TU_CS_MODE_EXTERNAL cs to emit
commands to.
Add tu_cs_mode and TU_CS_MODE_EXTERNAL. When in
TU_CS_MODE_EXTERNAL, tu_cs wraps an external buffer and can not
grow.
This also moves tu_cs* up in tu_private.h, such that other structs
can embed tu_cs_entry.
Error checking tu_cs_begin/tu_cs_end is too tedious for the callers.
Move tu_cs_add_bo and tu_cs_reserve_entry to tu_cs_reserve_space
such that tu_cs_begin/tu_cs_end never fails.
They are used like
tu_cs_reserve_space(...);
tu_cs_emit(...);
...;
tu_cs_reserve_space_assert();
to make sure we reserved enough space at the beginning.
Chia-I Wu
Bas Nieuwenhuizen