1. Fixed Size Arrays proposal
EPICS Developers Meeting 2014, Ljubljana, March 2014
Fixed Size Arrays proposal
Matej Sekoranja

2. Rationale, naming pvData knows only unbounded variable length arrays
Flexibility is good, but kills performance (does not allow optimizations)
In most cases arrays size if fixed or bounded
I propose:
variable size array, e.g. int[]
bounded size array, e.g. int<1024>
fixed size array, e.g. int[16]
bounded size string, e.g. string<40>

3. Required changes
Introspection interface API is affected, and its serialization
“PVArray” needs minor changes to handle limits
e.g. check if new capacity exceed maximum capacity, automatically allocate fixed size arrays
public class Array : public Field {
// 0 not valid value, means undefined
std::size_t getMaximumCapacity();
std::size_t getFixedLength(); }
public class ScalarArray / StructureArray / UnionArray : public Array {
. . .
public class StringScalar : public Scalar {
std::size_t getMaximumCapacity()

4. Thank you!