gno.land/p/moul/x/merkle/v0⧉

1package merkle23import "crypto/sha256"45// encodeSlices renders items in the wire shape crypto/merkle.HashFromByteSlices6// expects: a 4-byte big-endian count, then per item a 4-byte big-endian length7// followed by its bytes. The native side decodes this back into [][]byte; gno8// cannot hand a slice of slices to a native directly.9func encodeSlices(items [][]byte) []byte {10	n := 011	for _, it := range items {12		n += 4 + len(it)13	}14	out := make([]byte, 0, 4+n)15	out = appendBE32(out, len(items))16	for _, it := range items {17		out = appendBE32(out, len(it))18		out = append(out, it...)19	}20	return out21}2223func appendBE32(dst []byte, n int) []byte {24	return append(dst, byte(n>>24), byte(n>>16), byte(n>>8), byte(n))25}2627// hashSortedPair is the commutative node hash: SHA256 over the two children in28// ascending byte order, so a proof needs no left/right flag. Used only by29// VerifySorted.30func hashSortedPair(a, b []byte) []byte {31	d := make([]byte, 0, len(a)+len(b))32	if less(a, b) {33		d = append(append(d, a...), b...)34	} else {35		d = append(append(d, b...), a...)36	}37	h := sha256.Sum256(d)38	return h[:]39}4041// less reports a < b in lexicographic byte order. gno's bytes package is42// available, but keeping the comparison here keeps this package import-light.43func less(a, b []byte) bool {44	n := len(a)45	if len(b) < n {46		n = len(b)47	}48	for i := 0; i < n; i++ {49		if a[i] != b[i] {50			return a[i] < b[i]51		}52	}53	return len(a) < len(b)54}5556func equal(a, b []byte) bool {57	if len(a) != len(b) {58		return false59	}60	for i := range a {61		if a[i] != b[i] {62			return false63		}64	}65	return true66}67