feat: 4184 gguf parser (ai artifact cataloger) part 1 (#4279)

---------
Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>

syft/pkg/cataloger/ai/test_helpers_test.go

@@ -0,0 +1,128 @@
+package ai
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+// GGUF type constants for test builder
+// https://github.com/ggml-org/ggml/blob/master/docs/gguf.md
+const (
+	ggufMagic       = 0x46554747 // "GGUF" in little-endian
+	ggufTypeUint8   = 0
+	ggufTypeInt8    = 1
+	ggufTypeUint16  = 2
+	ggufTypeInt16   = 3
+	ggufTypeUint32  = 4
+	ggufTypeInt32   = 5
+	ggufTypeFloat32 = 6
+	ggufTypeBool    = 7
+	ggufTypeString  = 8
+	ggufTypeArray   = 9
+	ggufTypeUint64  = 10
+	ggufTypeInt64   = 11
+	ggufTypeFloat64 = 12
+)
+
+// testGGUFBuilder helps build GGUF files for testing
+type testGGUFBuilder struct {
+	buf         *bytes.Buffer
+	version     uint32
+	tensorCount uint64
+	kvPairs     []testKVPair
+}
+
+type testKVPair struct {
+	key       string
+	valueType uint32
+	value     interface{}
+}
+
+func newTestGGUFBuilder() *testGGUFBuilder {
+	return &testGGUFBuilder{
+		buf:         new(bytes.Buffer),
+		version:     3,
+		tensorCount: 0,
+		kvPairs:     []testKVPair{},
+	}
+}
+
+func (b *testGGUFBuilder) withVersion(v uint32) *testGGUFBuilder {
+	b.version = v
+	return b
+}
+
+func (b *testGGUFBuilder) withTensorCount(count uint64) *testGGUFBuilder {
+	b.tensorCount = count
+	return b
+}
+
+func (b *testGGUFBuilder) withStringKV(key, value string) *testGGUFBuilder {
+	b.kvPairs = append(b.kvPairs, testKVPair{key: key, valueType: ggufTypeString, value: value})
+	return b
+}
+
+func (b *testGGUFBuilder) withUint64KV(key string, value uint64) *testGGUFBuilder {
+	b.kvPairs = append(b.kvPairs, testKVPair{key: key, valueType: ggufTypeUint64, value: value})
+	return b
+}
+
+func (b *testGGUFBuilder) withUint32KV(key string, value uint32) *testGGUFBuilder {
+	b.kvPairs = append(b.kvPairs, testKVPair{key: key, valueType: ggufTypeUint32, value: value})
+	return b
+}
+
+func (b *testGGUFBuilder) writeString(s string) {
+	binary.Write(b.buf, binary.LittleEndian, uint64(len(s)))
+	b.buf.WriteString(s)
+}
+
+func (b *testGGUFBuilder) build() []byte {
+	// Write magic number "GGUF"
+	binary.Write(b.buf, binary.LittleEndian, uint32(ggufMagic))
+
+	// Write version
+	binary.Write(b.buf, binary.LittleEndian, b.version)
+
+	// Write tensor count
+	binary.Write(b.buf, binary.LittleEndian, b.tensorCount)
+
+	// Write KV count
+	binary.Write(b.buf, binary.LittleEndian, uint64(len(b.kvPairs)))
+
+	// Write KV pairs
+	for _, kv := range b.kvPairs {
+		// Write key
+		b.writeString(kv.key)
+		// Write value type
+		binary.Write(b.buf, binary.LittleEndian, kv.valueType)
+		// Write value based on type
+		switch kv.valueType {
+		case ggufTypeString:
+			b.writeString(kv.value.(string))
+		case ggufTypeUint32:
+			binary.Write(b.buf, binary.LittleEndian, kv.value.(uint32))
+		case ggufTypeUint64:
+			binary.Write(b.buf, binary.LittleEndian, kv.value.(uint64))
+		case ggufTypeUint8:
+			binary.Write(b.buf, binary.LittleEndian, kv.value.(uint8))
+		case ggufTypeInt32:
+			binary.Write(b.buf, binary.LittleEndian, kv.value.(int32))
+		case ggufTypeBool:
+			var v uint8
+			if kv.value.(bool) {
+				v = 1
+			}
+			binary.Write(b.buf, binary.LittleEndian, v)
+		}
+	}
+
+	return b.buf.Bytes()
+}
+
+// buildInvalidMagic creates a file with invalid magic number
+func (b *testGGUFBuilder) buildInvalidMagic() []byte {
+	buf := new(bytes.Buffer)
+	binary.Write(buf, binary.LittleEndian, uint32(0x12345678))
+	return buf.Bytes()
+}