1 files changed, 92 insertions, 0 deletions
diff --git a/buffers.go b/buffers.go
new file mode 100644
index 00000000..ab3a3b76
--- /dev/null
+++ b/buffers.go
@@ -0,0 +1,92 @@
+package furgit
+
+import "sync"
+
+const (
+	defaultBodyCap = 32 * 1024
+	maxPooledBody  = 8 << 20
+)
+
+type borrowedBody struct {
+	buf    []byte
+	pooled bool
+}
+
+var bodyPool = sync.Pool{
+	New: func() any {
+		buf := make([]byte, 0, defaultBodyCap)
+		return &buf
+	},
+}
+
+func borrowBody(capHint int) borrowedBody {
+	if capHint < defaultBodyCap {
+		capHint = defaultBodyCap
+	}
+	buf := bodyPool.Get().(*[]byte)
+	if cap(*buf) < capHint {
+		bodyPool.Put(buf)
+		newBuf := make([]byte, 0, capHint)
+		return borrowedBody{buf: newBuf, pooled: false}
+	}
+	slice := (*buf)[:0]
+	return borrowedBody{buf: slice, pooled: true}
+}
+
+func borrowedFromOwned(buf []byte) borrowedBody {
+	return borrowedBody{buf: buf}
+}
+
+func (b *borrowedBody) Resize(n int) {
+	if n < 0 {
+		n = 0
+	}
+	b.ensureCapacity(n)
+	b.buf = b.buf[:n]
+}
+
+func (b *borrowedBody) Append(src []byte) {
+	if len(src) == 0 {
+		return
+	}
+	start := len(b.buf)
+	b.ensureCapacity(start + len(src))
+	b.buf = b.buf[:start+len(src)]
+	copy(b.buf[start:], src)
+}
+
+func (b *borrowedBody) Bytes() []byte {
+	return b.buf
+}
+
+func (b *borrowedBody) Release() {
+	if b.buf == nil {
+		return
+	}
+	if b.pooled && cap(b.buf) <= maxPooledBody {
+		tmp := b.buf[:0]
+		bodyPool.Put(&tmp)
+	}
+	b.buf = nil
+	b.pooled = false
+}
+
+func (b *borrowedBody) ensureCapacity(needed int) {
+	if cap(b.buf) >= needed {
+		return
+	}
+	old := b.buf
+	wasPooled := b.pooled
+	newCap := cap(b.buf) * 2
+	if newCap < needed {
+		newCap = needed
+	}
+	newBuf := make([]byte, len(b.buf), newCap)
+	copy(newBuf, b.buf)
+	b.buf = newBuf
+	b.pooled = false
+	if wasPooled && cap(old) <= maxPooledBody {
+		tmp := old[:0]
+		bodyPool.Put(&tmp)
+	}
+}