An abstract type for keys

The type of values

Tells if a given key is already bound to a storage bucket. Consumes Gas_repr.read_bytes_cost Z.zero.

Retrieve a value from the storage bucket at a given key ; returns Storage_errorMissing_key if the key is not set ; returns Storage_errorCorrupted_data if the deserialisation fails. Consumes Gas_repr.read_bytes_cost <size of the value>.

Retrieve a value from the storage bucket at a given key ; returns None if the value is not set ; returns Storage_error Corrupted_data if the deserialisation fails. Consumes Gas_repr.read_bytes_cost <size of the value> if present or Gas_repr.read_bytes_cost Z.zero.

Updates the content of a bucket ; returns A Storage_Error Missing_key if the value does not exists. Consumes serialization cost. Consumes Gas_repr.write_bytes_cost <size of the new value>. Returns the difference from the old to the new size.

Allocates a storage bucket at the given key and initializes it ; returns a Storage_errorExisting_key if the bucket exists. Consumes serialization cost. Consumes Gas_repr.write_bytes_cost <size of the value>. Returns the size.

Allocates a storage bucket at the given key and initializes it with a value ; just updates it if the bucket exists. Consumes serialization cost. Consumes Gas_repr.write_bytes_cost <size of the new value>. Returns the difference from the old (maybe 0) to the new size.

When the value is Some v, allocates the data and initializes it with v ; just updates it if the bucket exists. When the valus is None, delete the storage bucket when the value ; does nothing if the bucket does not exists. Consumes serialization cost. Consumes the same gas cost as either remove or init_set. Returns the difference from the old (maybe 0) to the new size.

Delete a storage bucket and its contents ; returns a Storage_errorMissing_key if the bucket does not exists. Consumes Gas_repr.write_bytes_cost Z.zero. Returns the freed size.

Removes a storage bucket and its contents ; does nothing if the bucket does not exists. Consumes Gas_repr.write_bytes_cost Z.zero. Returns the freed size.