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Blob

Reference for mo:core/Blob in the core library.

Blob is the binary value surface for serialization, certified data, and principal conversions. Its conversion and hashing functions are trusted runtime wrappers; Blob.Spec.size is the proof-facing abstraction used by contracts.

Import​

mo:core/Blob

Status​

  • Runtime module

Public API​

Types​

  • Blob

Modules​

  • Spec

Functions​

empty() : Blob​

Constructs the empty value for this module's data structure.

Contract

ensures size(result) == 0;
ensures isEmpty(result);

Use when: code or specifications need this operation with the documented contract.

isEmpty(blob : Blob) : Bool​

Checks the predicate described by the return contract.

Contract

ensures result == (size(blob) == 0);

Use when: a branch condition or contract needs this predicate as a named fact.

size(blob : Blob) : Nat​

Returns the length or cardinality represented by the value.

Contract

ensures result == Spec.size(blob);

Use when: code or specifications need this operation with the documented contract.

fromArray(bytes : [Nat8]) : Blob​

Converts between the module type and the target representation.

Contract

ensures size(result) == bytes.size();

Use when: crossing between this module's value and another representation.

fromVarArray(bytes : [var Nat8]) : Blob​

Converts between the module type and the target representation.

Contract

ensures size(result) == bytes.size();

Use when: crossing between this module's value and another representation.

toArray(blob : Blob) : [Nat8]​

Converts between the module type and the target representation.

Contract

ensures result.size() == size(blob);

Use when: crossing between this module's value and another representation.

toVarArray(blob : Blob) : [var Nat8]​

Converts between the module type and the target representation.

Contract

ensures result.size() == size(blob);

Use when: crossing between this module's value and another representation.

hash(blob : Blob) : Types.Hash​

Computes the core hash value for a blob.

Use when: code needs the core hash value for a blob.

compare(b1 : Blob, b2 : Blob) : Types.Order​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == #less ==> b1 < b2;
ensures result == #equal ==> b1 == b2;
ensures result == #greater ==> b1 > b2;
ensures b1 < b2 ==> result == #less;
ensures b1 == b2 ==> result == #equal;
ensures b1 > b2 ==> result == #greater;

Use when: code or contracts need an explicit comparison helper instead of an operator.

equal(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 == blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

notEqual(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 != blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

less(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 < blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

lessOrEqual(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 <= blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

greater(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 > blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

greaterOrEqual(blob1 : Blob, blob2 : Blob) : Bool​

Compares the supplied values and relates the result to the underlying order.

Contract

ensures result == (blob1 >= blob2);

Use when: code or contracts need an explicit comparison helper instead of an operator.

Spec Module​

Spec Functions​

size(blob : Blob) : Nat​

Provides a ghost/spec-only abstraction for contracts and proofs.

Use when: Use in contracts, ghost code, or lemmas when the runtime value needs an abstract proof model.

Summary​

  • Runtime module under mo:core/Blob.
  • Exposes 15 public functions.
  • Includes 1 spec helpers in Spec.