std.bytes

Pebble 0.3.1 · all symbols on this page are stable.

Monomorphic helpers over bytes, exposing every byte-string operation as a first-class function. Use these for partial application or as arguments to higher-order code; prefer operator forms (==, <, +) and methods (b.length()) in regular code.

Methods

Function	Description
length(b: bytes): int	Number of bytes.
slice(start: int, len: int, b: bytes): bytes	len-byte sub-string starting at start. Clips on out-of-range.
prepend(byteVal: int, b: bytes): bytes	Prepend a single byte (0–255). Fails if byteVal is out of range.
concat(a: bytes, b: bytes): bytes	Concatenate two byte strings.
indexAt(b: bytes, i: int): int	Byte at index i as an int 0–255. Fails on out-of-range.
equals(a: bytes, b: bytes): bool	Equality.
lessThan(a: bytes, b: bytes): bool	Lexicographic less-than.
lessThanEquals(a: bytes, b: bytes): bool	Lexicographic less-than-or-equal.
greaterThan(a: bytes, b: bytes): bool	Lexicographic greater-than.
greaterThanEquals(a: bytes, b: bytes): bool	Lexicographic greater-than-or-equal.
toInt(b: bytes): int	Decode big-endian unsigned integer.
fromInt(n: int): bytes	Encode n as the shortest big-endian unsigned byte string.

Examples

using {
    length, slice, prepend, concat, indexAt,
    equals, lessThan, lessThanEquals, greaterThan, greaterThanEquals,
    toInt, fromInt
} = std.bytes;

const n:    int   = length(#deadbeef);                     // 4
const sub:  bytes = slice(1, 2, #deadbeef);                // #adbe
const pre:  bytes = prepend(0xff, #beef);                  // #ffbeef
const cat:  bytes = concat(#dead, #beef);                  // #deadbeef
const at:   int   = indexAt(#deadbeef, 0);                 // 222 (0xde)
const eq:   bool  = equals(#ab, #ab);                      // true
const lt:   bool  = lessThan(#ab, #cd);                    // true
const le:   bool  = lessThanEquals(#ab, #ab);              // true
const gt:   bool  = greaterThan(#cd, #ab);                 // true
const ge:   bool  = greaterThanEquals(#ab, #ab);           // true
const i:    int   = toInt(#04d2);                          // 1234
const enc:  bytes = fromInt(1234);                         // #04d2

See also

• bytes — method-call form
• std.builtins — finer-grained byte string and bitwise builtins
• std.crypto — hash functions consume bytes