These functions are useful when serializing an unknown number of items
to a blob. The caller can first save the current offset, write a
placeholder uint32, write out (and count) the items, then use
blob_overwrite_uint32 with the saved offset to replace the placeholder
value.
Then, when deserializing, the reader will first read the count and
know how many subsequent items to expect.
(I wrote this code after reading a very similar patch written by
Tapani when he wrote serialization code for IR. Since I re-used the
idea of his code so directly, I've credited him as the author of this
code. --Carl)
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
This new interface allows for writing a series of objects to a chunk
of memory (a "blob").. The allocated memory is maintained within the
blob itself, (and re-allocated by doubling when necessary).
There are also functions for reading objects from a blob as well. If
code attempts to read beyond the available memory, the read functions
return 0 values (or its moral equivalent) without reading past the
allocated memory. Once the caller is done with the reads, it can check
blob->overrun to ensure whether any invalid values were previously
returned due to attempts to read too far.
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Emil Velikov
Tapani Pälli
Carl Worth