cf::hash

Functions

	Name
constexpruint64_t	fnv1a64(constchar * str, uint64_t seed =fnv1a64_offset_basis) FNV-1a 64-bit hash constexpr implementation.
constexpruint64_t	fnv1a64(std::string_view sv, uint64_t seed =fnv1a64_offset_basis) FNV-1a 64-bit hash for std::string_view (runtime/constexpr).
constexpruint32_t	fnv1a32(constchar * str, uint32_t seed =fnv1a32_offset_basis) FNV-1a 32-bit hash constexpr implementation.
constexpruint32_t	fnv1a32(std::string_view sv, uint32_t seed =fnv1a32_offset_basis) FNV-1a 32-bit hash for std::string_view.
constexpruint64_t	operator""_hash(constchar * str, size_t ) User-defined literal for compile-time FNV-1a 64-bit hashing.

Attributes

	Name
constexpruint64_t	fnv1a64_offset_basis FNV-1a 64-bit offset basis.
constexpruint64_t	fnv1a64_prime FNV-1a 64-bit prime.
constexpruint32_t	fnv1a32_offset_basis FNV-1a 32-bit offset basis.
constexpruint32_t	fnv1a32_prime FNV-1a 32-bit prime.

Functions Documentation

function fnv1a64

constexpruint64_t fnv1a64(
    constchar * str,
    uint64_t seed =fnv1a64_offset_basis
)

FNV-1a 64-bit hash constexpr implementation.

Parameters:

• str Null-terminated string to hash.
• seed Starting hash value (default: FNV offset basis).

Exceptions:

• None.

Return: 64-bit hash value.

Since: 0.1

Note: The hash is computed at compile time for string literals.

Warning: Different inputs may produce the same hash (collision). Use string comparison as fallback when hashes match.

Computes FNV-1a hash at compile time for string literals. The FNV-1a algorithm provides excellent distribution and minimal collisions for string identifiers.

constexpr uint64_t h1 = fnv1a64("TokenA");  // Compile-time
constexpr uint64_t h2 = fnv1a64("TokenB");  // Different value
static_assert(h1 != h2, "Hash collision!");

function fnv1a64

constexpruint64_t fnv1a64(
    std::string_view sv,
    uint64_t seed =fnv1a64_offset_basis
)

FNV-1a 64-bit hash for std::string_view (runtime/constexpr).

Parameters:

• sv String view to hash.
• seed Starting hash value (default: FNV offset basis).

Exceptions:

• None.

Return: 64-bit hash value.

Since: 0.1

Note: This function can be evaluated at compile time if the input is a constant expression.

Warning: Different inputs may produce the same hash (collision). Use string comparison as fallback when hashes match.

function fnv1a32

constexpruint32_t fnv1a32(
    constchar * str,
    uint32_t seed =fnv1a32_offset_basis
)

FNV-1a 32-bit hash constexpr implementation.

Parameters:

• str Null-terminated string to hash.
• seed Starting hash value (default: FNV offset basis).

Exceptions:

• None.

Return: 32-bit hash value.

Since: 0.1

Note: The hash is computed at compile time for string literals.

Warning: Different inputs may produce the same hash (collision). Use string comparison as fallback when hashes match.

function fnv1a32

constexpruint32_t fnv1a32(
    std::string_view sv,
    uint32_t seed =fnv1a32_offset_basis
)

FNV-1a 32-bit hash for std::string_view.

Parameters:

• sv String view to hash.
• seed Starting hash value (default: FNV offset basis).

Exceptions:

• None.

Return: 32-bit hash value.

Since: 0.1

Note: This function can be evaluated at compile time if the input is a constant expression.

Warning: Different inputs may produce the same hash (collision). Use string comparison as fallback when hashes match.

function operator""_hash

constexpruint64_t operator""_hash(
    constchar * str,
    size_t 
)

User-defined literal for compile-time FNV-1a 64-bit hashing.

Parameters:

• str Null-terminated string to hash.
• len Length of the string (unused, required by UDL syntax).

Exceptions:

• None.

Return: 64-bit hash value.

Since: 0.1

Note: This function is constexpr and evaluated at compile time.

Warning: None.

Enables syntax: "TokenName"_hash for compile-time hash computation.

constexpr uint64_t h = "MyToken"_hash;  // Compile-time hash
static_assert(h == fnv1a64("MyToken"), "Hash must match");

Attributes Documentation

variable fnv1a64_offset_basis

constexpruint64_t fnv1a64_offset_basis = 14695981039346656037ULL;

FNV-1a 64-bit offset basis.

Since: 0.1

variable fnv1a64_prime

constexpruint64_t fnv1a64_prime = 1099511628211ULL;

FNV-1a 64-bit prime.

Since: 0.1

variable fnv1a32_offset_basis

constexpruint32_t fnv1a32_offset_basis = 2166136261U;

FNV-1a 32-bit offset basis.

Since: 0.1

variable fnv1a32_prime

constexpruint32_t fnv1a32_prime = 16777619U;

FNV-1a 32-bit prime.

Since: 0.1

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Updated on 2026-03-09 at 10:14:00 +0000