Initial QSfera import

Server/vendor/github.com/lestrrat-go/jwx/v3/internal/ecutil/BUILD.bazel

@@ -0,0 +1,14 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "ecutil",
+    srcs = ["ecutil.go"],
+    importpath = "github.com/lestrrat-go/jwx/v3/internal/ecutil",
+    visibility = ["//:__subpackages__"],
+)
+
+alias(
+    name = "go_default_library",
+    actual = ":ecutil",
+    visibility = ["//:__subpackages__"],
+)

Server/vendor/github.com/lestrrat-go/jwx/v3/internal/ecutil/ecutil.go

@@ -0,0 +1,76 @@
+// Package ecutil defines tools that help with elliptic curve related
+// computation
+package ecutil
+
+import (
+	"crypto/elliptic"
+	"math/big"
+	"sync"
+)
+
+const (
+	// size of buffer that needs to be allocated for EC521 curve
+	ec521BufferSize = 66 // (521 / 8) + 1
+)
+
+var ecpointBufferPool = sync.Pool{
+	New: func() any {
+		// In most cases the curve bit size will be less than this length
+		// so allocate the maximum, and keep reusing
+		buf := make([]byte, 0, ec521BufferSize)
+		return &buf
+	},
+}
+
+func getCrvFixedBuffer(size int) []byte {
+	//nolint:forcetypeassert
+	buf := *(ecpointBufferPool.Get().(*[]byte))
+	if size > ec521BufferSize && cap(buf) < size {
+		buf = append(buf, make([]byte, size-cap(buf))...)
+	}
+	return buf[:size]
+}
+
+// ReleaseECPointBuffer releases the []byte buffer allocated.
+func ReleaseECPointBuffer(buf []byte) {
+	buf = buf[:cap(buf)]
+	buf[0] = 0x0
+	for i := 1; i < len(buf); i *= 2 {
+		copy(buf[i:], buf[:i])
+	}
+	buf = buf[:0]
+	ecpointBufferPool.Put(&buf)
+}
+
+func CalculateKeySize(crv elliptic.Curve) int {
+	// We need to create a buffer that fits the entire curve.
+	// If the curve size is 66, that fits in 9 bytes. If the curve
+	// size is 64, it fits in 8 bytes.
+	bits := crv.Params().BitSize
+
+	// For most common cases we know before hand what the byte length
+	// is going to be. optimize
+	var inBytes int
+	switch bits {
+	case 224, 256, 384: // TODO: use constant?
+		inBytes = bits / 8
+	case 521:
+		inBytes = ec521BufferSize
+	default:
+		inBytes = bits / 8
+		if (bits % 8) != 0 {
+			inBytes++
+		}
+	}
+
+	return inBytes
+}
+
+// AllocECPointBuffer allocates a buffer for the given point in the given
+// curve. This buffer should be released using the ReleaseECPointBuffer
+// function.
+func AllocECPointBuffer(v *big.Int, crv elliptic.Curve) []byte {
+	buf := getCrvFixedBuffer(CalculateKeySize(crv))
+	v.FillBytes(buf)
+	return buf
+}