carray: bug sweep.

The carray type is hereby reviewed for and repaired of issues
related to the nelem member of struct carray using negative
values to indicate "unknown carray size".

* ffi.c (struct carray): The artype becomes a two-element
array of values, so a carray can have a cache of separate
null-terminated and non-null-terminated array type
descriptors. This way, we get rid of the dirty trick of
mutating one type.
(carray_mark_op): Mark the two-element artype.
(make_carray): Initialize two-element artype to nil.
(carray_set_length): Cache invalidation: reset both elements
of artype to nil, because the type includes length
information, which may now be wrong.
(copy_carray): Throw exception if asked to copy carray of
unknown length. This would happen in carray_dup anyway,
but at least the diagnostic refers to copy-carray.
(buf_carray): Avoid calling make_duplicate_buf with negative
bytes value when the carray has unknown length; diagnose.
(carray_ref, carray_refset): Don't translate negative index
values if the length is unknown.
(carray_sub, carray_replace): If the operation requires
use of the length, and it is unknown, throw an
exception.
(carray_ensure_artype): Take a null_term paramter that is 0
or 1, and use it as an array index into artype to set up the
correct type, with the correct value of the null_term
member that is henceforth not mutated.
(carray_get_common, carray_put_common): Pass the null_term
argument down to carray_ensure_artype.
Remove the mutation of the null_term member of the type
structure.

0 files changed, 0 insertions, 0 deletions