some headers were not including port_def.inc
some headers were not declaring extern "C"
some headers were backing out of the above in the wrong order
PiperOrigin-RevId: 457391878
Now that 'size' has been renamed as 'capacity' we are free to rename 'len' as
'size', so upb_Array_Size() is actually returning the 'size' field.
PiperOrigin-RevId: 456865972
The current field/function names for upb_Array are quite confusing.
We will fix them in two steps, this being the first step.
PiperOrigin-RevId: 456687224
Lots of changes but it's all just moving things around.
Backward-compatible stub #include's have been provided for now.
upb_Arena/upb_Status have been split out from upb/upb.?
upb_Array/upb_Map/upb_MessageValue have been split out from upb/collections.?
upb_ExtensionRegistry has been split out from upb/msg.?
upb/decode_internal.h is now upb/internal/decode.h
upb/mini_table_accessors_internal.h is now upb/internal/mini_table_accessors.h
upb/table_internal.h is now upb/internal/table.h
upb/upb_internal.h is now upb/internal/upb.h
PiperOrigin-RevId: 456297617
upb has traditionally returned 16-byte-aligned pointers from arena allocation. This was out of an abundance of caution, since users could theoretically be using upb arenas to allocate memory that is then used for SSE/AVX values (eg. [`__m128`](https://docs.microsoft.com/en-us/cpp/cpp/m128?view=msvc-170), which require 16-byte alignment.
In practice, the protobuf C++ arena has used 8-byte alignment for 8 years with no significant problems I know of arising from SSE etc.
Reducing the alignment requirement to 8 will save memory. It will also help with compatibility on 32-bit architectures where `malloc()` only returns 8-byte aligned memory. The immediate motivation is to fix the win32 build for Python protobuf.
PiperOrigin-RevId: 448331777
An enum MiniDescriptor simply encodes a set of valid `int32_t` values, so that the protobuf parser can test whether a given enum value is known or not.
The format implemented here is novel and needs to be documented. In short, the format is:
1. base92 values 0-31: 5-bit mask indicating presence or absence of the next five enum values.
2. base92 values 60-91: varint indicating skip over a region of enum values.
Negative enum values are encoded as their `uint32_t` equivalent.
PiperOrigin-RevId: 442892799