The public API for Crunch. More...

Namespaces
namespace	detail
	Internal implementation details for Crunch's public API.

namespace	integrity
	Integrity policies for verifying message correctness.

Classes
struct	Around
	Validates that a floating-point value is within a tolerance of a target. More...

struct	CrunchHeader
	Represents the standard Crunch message header. More...

struct	EqualTo
	Validates that a value equals a compile-time threshold. More...

struct	Error
	Represents an error occurred during Crunch operations. More...

struct	Even
	Validates that an integral value is even. More...

struct	False
	Validates that a boolean value is false. More...

struct	FixedString

struct	GreaterThan
	Validates that a value is greater than a compile-time threshold. More...

struct	GreaterThanOrEqualTo
	Validates that a value is greater than or equal to a compile-time threshold. More...

struct	IsFinite
	Validates that a floating-point value is finite (not NaN or Inf). More...

struct	Length
	Validates that a string-like or container value has a specific length. More...

struct	LengthAtLeast
	Validates that a container has at least N elements. More...

struct	LengthAtMost
	Validates that a container has at most N elements. More...

struct	LessThan
	Validates that a value is less than a compile-time threshold. More...

struct	LessThanOrEqualTo
	Validates that a value is less than or equal to a compile-time threshold. More...

struct	Negative
	Validates that a value is strictly negative (< 0). More...

struct	None
	Validates nothing (always succeeds). More...

struct	NotEqualTo
	Validates that a value does not equal a compile-time threshold. More...

struct	NotZero
	Validates that a value is not zero. More...

struct	NullTerminated
	Validates that a string does not contain embedded nulls. More...

struct	Odd
	Validates that an integral value is odd. More...

struct	OneOf
	Validates that a value is one of a set of compile-time values. More...

struct	Optional
	Presence validator allowing an optional field (can be unset). More...

struct	Positive
	Validates that a value is non-negative (>= 0). More...

struct	Required
	Presence validator enforcing that a field MUST be set. More...

struct	StringEquals
	Validates that a string equals a compile-time string. More...

struct	StringNotEquals
	Validates that a string does not equal a compile-time string. More...

struct	True
	Validates that a boolean value is true. More...

struct	Unique
	Validates that a container has unique elements. More...

Concepts
concept	IntegrityPolicy
	Concept defining the interface for message integrity policies.

concept	SerdesPolicy
	Concept defining a Serialization/Deserialization policy.

concept	Validator
	Concept defining a value validator.

concept	IsPresenceValidator
	Concept for validators that check field presence semantics.

Typedefs
using	FieldId = int32_t
	Unique identifier for a field within a Crunch message.

using	MessageId = int32_t
	Unique identifier for a message type.

using	CrunchVersionId = uint8_t
	Version identifier for the Crunch library.

Enumerations
enum class	Format : uint8_t { Packed = 0x01 , Aligned4 = 0x02 , Aligned8 = 0x03 , TLV = 0x04 }
	Serialization format identifier stored in the message header. More...

enum class	ErrorCode : uint8_t { UNKNOWN = 0 , IntegrityCheckFailed , DeserializationError , ValidationFailed , InvalidMessageId , InvalidFormat , CapacityExceeded }
	Error codes representing various failure conditions in Crunch. More...

Functions
template<typename T > requires std::integral<T> \|\| std::is_enum_v<T> \|\| std::floating_point<T>
constexpr T	LittleEndian (T value) noexcept
	Converts a value to/from Little Endian byte order.

constexpr std::expected< CrunchHeader, Error >	GetHeader (std::span< const std::byte > input) noexcept
	Parses and returns a copy of the header from the input buffer.

template<typename Message , typename Serdes >
constexpr std::size_t	WriteHeader (std::span< std::byte > output) noexcept
	Writes the standard header to the output buffer.

template<typename Message , typename Serdes >
constexpr std::expected< std::size_t, Error >	ValidateHeader (std::span< const std::byte > input) noexcept
	Validates the header and returns offset after header on success.

template<messages::CrunchMessage Message, typename Integrity , typename Serdes > requires IntegrityPolicy<Integrity> && SerdesPolicy<Serdes, Message>
constexpr auto	GetBuffer () noexcept
	Creates a correctly sized Buffer for the given configuration.

template<messages::CrunchMessage Message>
constexpr auto	Validate (const Message &message) noexcept -> std::optional< Error >
	Validates a message (field presence + message-level validation).

template<typename BufferType , typename Message > requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>
constexpr auto	Serialize (BufferType &buffer, const Message &message) noexcept -> std::optional< Error >
	Serializes a message into the provided buffer.

template<typename BufferType , typename Message > requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>
constexpr void	SerializeWithoutValidation (BufferType &buffer, const Message &message) noexcept
	Serializes a message into the provided buffer without validation.

template<typename BufferType , typename Message > requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>
constexpr auto	Deserialize (const BufferType &buffer, Message &out_message) -> std::optional< Error >
	Deserializes a message from a buffer.

Detailed Description

The public API for Crunch.

This section contains all the interfaces for serializing and deserializing messages, and transitively provides the necessary types for defining messages and fields.

Top-level APIs

GetBuffer: Creates a strongly-typed buffer of the maximum serialized message size for a given Message, Integrity, and Serdes combination.
Validate: Validates field presence and message-level constraints.
Serialize: Validates and writes a message into a buffer, appending integrity checks.
Deserialize: Verifies integrity and reads a message from a buffer.

Enumeration Type Documentation

◆ ErrorCode

enum class Crunch::ErrorCode : uint8_t

strong

Error codes representing various failure conditions in Crunch.

Enumerator
UNKNOWN	Unknown error.
IntegrityCheckFailed	Message integrity check failed (e.g., CRC mismatch).
DeserializationError	Error parsing or decoding message data.
ValidationFailed	Field or message logical validation failed.
InvalidMessageId	Message ID in header does not match expected ID.
InvalidFormat	Serialization format in header does not match expected format.
CapacityExceeded	Data exceeds the capacity of the backing storage.

◆ Format

enum class Crunch::Format : uint8_t

strong

Serialization format identifier stored in the message header.

Enumerator
Packed	No alignment padding (Alignment = 1).
Aligned4	4-byte alignment padding.
Aligned8	8-byte alignment padding.
TLV	Tag-Length-Value encoding.

Function Documentation

◆ Deserialize()

template<typename BufferType , typename Message >
requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>

constexpr auto Crunch::Deserialize	(	const BufferType &	buffer,
		Message &	out_message
	)		-> std::optional<Error>

constexpr

Deserializes a message from a buffer.

Verifies the integrity of the buffer, then attempts to deserialize the content into a Message object.

Constraints:

BufferType must be an instantiation of Crunch::Buffer.
Message must satisfy the CrunchMessage concept.
BufferType::MessageType must be the same as Message.

Template Parameters

BufferType	The Buffer type
Message	The CrunchMessage type to deserialize into.

Parameters

buffer	The source Buffer to read from.
out_message	Output parameter for the deserialized message.

Returns: std::optional<Error> std::nullopt on success, or an Error (Integrity/Deserialization).

◆ GetBuffer()

template<messages::CrunchMessage Message, typename Integrity , typename Serdes >
requires IntegrityPolicy<Integrity> && SerdesPolicy<Serdes, Message>

constexpr auto Crunch::GetBuffer ( )

constexprnoexcept

Creates a correctly sized Buffer for the given configuration.

This function calculates the exact size required for the message serialization plus any integrity overhead at compile time.

Template Parameters

Message	The CrunchMessage type.
Integrity	The IntegrityPolicy (e.g., integrity::None, integrity::CRC16).
Serdes	The SerdesPolicy (e.g., serdes::PackedLayout).

Returns: A Buffer object ready for use with Serialize/Deserialize.

◆ GetHeader()

constexpr std::expected< CrunchHeader, Error > Crunch::GetHeader ( std::span< const std::byte > input )

constexprnoexcept

Parses and returns a copy of the header from the input buffer.

Parameters

input The input buffer.

Returns: The parsed header on success, or an Error if the buffer is too small.

◆ LittleEndian()

template<typename T >
requires std::integral<T> || std::is_enum_v<T> || std::floating_point<T>

constexpr T Crunch::LittleEndian ( T value )

constexprnoexcept

Converts a value to/from Little Endian byte order.

Template Parameters

T	The type of the value to convert. Must be an integral type or enum.

Parameters

value The value to convert.

Returns: The converted value.

◆ Serialize()

template<typename BufferType , typename Message >
requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>

constexpr auto Crunch::Serialize	(	BufferType &	buffer,
		const Message &	message
	)		-> std::optional<Error>

constexprnoexcept

Serializes a message into the provided buffer.

Validates the message content, serializes it according to the Serdes policy, and applies the Integrity policy (e.g., checksum).

Constraints:

BufferType must be an instantiation of Crunch::Buffer.
Message must satisfy the CrunchMessage concept.
BufferType::MessageType must be the same as Message.

Template Parameters

BufferType	The Buffer type (deduced from buffer parameter).
Message	The CrunchMessage type to serialize.

Parameters

buffer	The destination Buffer (must match Message type).
message	The message to serialize.

Returns: std::optional<Error> std::nullopt on success, or an Error if validation fails.

◆ SerializeWithoutValidation()

template<typename BufferType , typename Message >
requires IsBuffer<BufferType> && messages::CrunchMessage<Message> && std::same_as<typename BufferType::MessageType, Message>

constexpr void Crunch::SerializeWithoutValidation	(	BufferType &	buffer,
		const Message &	message
	)

constexprnoexcept

Serializes a message into the provided buffer without validation.

Does strictly serialization logic (header, payload, checksum) without running any validation checks. Useful for forwarding invalid messages, testing, or performance-critical paths where validation is done elsewhere.

Template Parameters

BufferType	The Buffer type
Message	The CrunchMessage type to serialize.

Parameters

buffer	The destination Buffer (must match Message type).
message	The message to serialize.

◆ Validate()

template<messages::CrunchMessage Message>

constexpr auto Crunch::Validate ( const Message & message ) -> std::optional<Error>

constexprnoexcept

Validates a message (field presence + message-level validation).

First validates that all required fields are set, then calls the message's custom Validate() method for any cross-field or business logic validation.

Note: This API does not execute field validators. Field validators are executed by the fields on-set.; In the future, this will also validate submessages and run aggregate field validation.

Template Parameters

Message The CrunchMessage type to validate.

Parameters

message The message to validate.

Returns: std::optional<Error> std::nullopt on success, or an Error if validation fails.

◆ ValidateHeader()

template<typename Message , typename Serdes >

constexpr std::expected< std::size_t, Error > Crunch::ValidateHeader ( std::span< const std::byte > input )

constexprnoexcept

Validates the header and returns offset after header on success.

Checks:

Buffer is large enough
Version matches CrunchVersion
Format matches Serdes::GetFormat()
MessageId matches Message::message_id

Template Parameters

Message	The expected message type.
Serdes	The expected serialization policy.

Parameters

input The input buffer.

Returns: Offset after header on success, or an Error.

◆ WriteHeader()

template<typename Message , typename Serdes >

constexpr std::size_t Crunch::WriteHeader ( std::span< std::byte > output )

constexprnoexcept

Writes the standard header to the output buffer.

Template Parameters

Message	The message type (provides message_id).
Serdes	The serialization policy (provides format).

Parameters

output The output buffer.

Returns: The number of bytes written (always StandardHeaderSize).

Namespaces

Classes

Concepts

Typedefs

Enumerations

Functions

Detailed Description

Top-level APIs

Enumeration Type Documentation

◆ ErrorCode

◆ Format

Function Documentation

◆ Deserialize()

◆ GetBuffer()

◆ GetHeader()

◆ LittleEndian()

◆ Serialize()

◆ SerializeWithoutValidation()

◆ Validate()

◆ ValidateHeader()

◆ WriteHeader()