Implement Modrinth pack exporting (fixes #34)

curseforge/murmur2/hash.go

@@ -0,0 +1,54 @@
+package murmur2
+
+import (
+	"encoding/binary"
+	"github.com/aviddiviner/go-murmur"
+	"hash"
+)
+
+func New() hash.Hash32 {
+	return &Murmur2CF{buf: make([]byte, 0)}
+}
+
+type Murmur2CF struct {
+	// Can't be done incrementally, since it is seeded with the length of the input!
+	buf []byte
+}
+
+func (m *Murmur2CF) Write(p []byte) (n int, err error) {
+	for _, b := range p {
+		if !isWhitespaceCharacter(b) {
+			m.buf = append(m.buf, b)
+		}
+	}
+	return len(p), nil
+}
+
+// CF modification: strips whitespace characters
+func isWhitespaceCharacter(b byte) bool {
+	return b == 9 || b == 10 || b == 13 || b == 32
+}
+
+func (m *Murmur2CF) Sum(b []byte) []byte {
+	if b == nil {
+		b = make([]byte, 4)
+	}
+	binary.BigEndian.PutUint32(b, murmur.MurmurHash2(m.buf, 1))
+	return b
+}
+
+func (m *Murmur2CF) Reset() {
+	m.buf = make([]byte, 0)
+}
+
+func (m *Murmur2CF) Size() int {
+	return 4
+}
+
+func (m *Murmur2CF) BlockSize() int {
+	return 4
+}
+
+func (m *Murmur2CF) Sum32() uint32 {
+	return binary.BigEndian.Uint32(m.Sum(nil))
+}