go-nostr/utils.go

package nostr

import (
	"strings"

	"golang.org/x/exp/constraints"
)

func similar[E constraints.Ordered](as, bs []E) bool {
	if len(as) != len(bs) {
		return false
	}

	for _, a := range as {
		for _, b := range bs {
			if b == a {
				goto next
			}
		}
		// didn't find a B that corresponded to the current A
		return false

	next:
		continue
	}

	return true
}

func containsPrefixOf(haystack []string, needle string) bool {
	for _, hay := range haystack {
		if strings.HasPrefix(needle, hay) {
			return true
		}
	}
	return false
}

// Escaping strings for JSON encoding according to RFC8259.
// Also encloses result in quotation marks "".
func escapeString(dst []byte, s string) []byte {
	dst = append(dst, '"')
	for i := 0; i < len(s); i++ {
		c := s[i]
		switch {
		case c == '"':
			// quotation mark
			dst = append(dst, []byte{'\\', '"'}...)
		case c == '\\':
			// reverse solidus
			dst = append(dst, []byte{'\\', '\\'}...)
		case c >= 0x20:
			// default, rest below are control chars
			dst = append(dst, c)
		case c == 0x08:
			dst = append(dst, []byte{'\\', 'b'}...)
		case c < 0x09:
			dst = append(dst, []byte{'\\', 'u', '0', '0', '0', '0' + c}...)
		case c == 0x09:
			dst = append(dst, []byte{'\\', 't'}...)
		case c == 0x0a:
			dst = append(dst, []byte{'\\', 'n'}...)
		case c == 0x0c:
			dst = append(dst, []byte{'\\', 'f'}...)
		case c == 0x0d:
			dst = append(dst, []byte{'\\', 'r'}...)
		case c < 0x10:
			dst = append(dst, []byte{'\\', 'u', '0', '0', '0', 0x57 + c}...)
		case c < 0x1a:
			dst = append(dst, []byte{'\\', 'u', '0', '0', '1', 0x20 + c}...)
		case c < 0x20:
			dst = append(dst, []byte{'\\', 'u', '0', '0', '1', 0x47 + c}...)
		}
	}
	dst = append(dst, '"')
	return dst
}