feat: incremental gguf parser (#10822)

* incremental gguf parser
* gguf: update test to not rely on gguf on disc
* re-use existing create gguf
* read capabilities from gguf kv
* kv exists
* update tests
* s/doneFunc/successFunc/g
* new buffered reader

---------

Co-authored-by: Bruce MacDonald <brucewmacdonald@gmail.com>

fs/gguf/keyvalue.go

@@ -0,0 +1,90 @@
+package gguf
+
+import (
+	"reflect"
+	"slices"
+)
+
+type KeyValue struct {
+	Key string
+	Value
+}
+
+func (kv KeyValue) Valid() bool {
+	return kv.Key != "" && kv.Value.value != nil
+}
+
+type Value struct {
+	value any
+}
+
+func value[T any](v Value, kinds ...reflect.Kind) (t T) {
+	vv := reflect.ValueOf(v.value)
+	if slices.Contains(kinds, vv.Kind()) {
+		t = vv.Convert(reflect.TypeOf(t)).Interface().(T)
+	}
+	return
+}
+
+func values[T any](v Value, kinds ...reflect.Kind) (ts []T) {
+	switch vv := reflect.ValueOf(v.value); vv.Kind() {
+	case reflect.Slice:
+		if slices.Contains(kinds, vv.Type().Elem().Kind()) {
+			ts = make([]T, vv.Len())
+			for i := range vv.Len() {
+				ts[i] = vv.Index(i).Convert(reflect.TypeOf(ts[i])).Interface().(T)
+			}
+		}
+	}
+	return
+}
+
+// Int returns Value as a signed integer. If it is not a signed integer, it returns 0.
+func (v Value) Int() int64 {
+	return value[int64](v, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64)
+}
+
+// Ints returns Value as a signed integer slice. If it is not a signed integer slice, it returns nil.
+func (v Value) Ints() (i64s []int64) {
+	return values[int64](v, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64)
+}
+
+// Uint converts an unsigned integer value to uint64. If the value is not a unsigned integer, it returns 0.
+func (v Value) Uint() uint64 {
+	return value[uint64](v, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64)
+}
+
+// Uints returns Value as a unsigned integer slice. If it is not a unsigned integer slice, it returns nil.
+func (v Value) Uints() (u64s []uint64) {
+	return values[uint64](v, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64)
+}
+
+// Float returns Value as a float. If it is not a float, it returns 0.
+func (v Value) Float() float64 {
+	return value[float64](v, reflect.Float32, reflect.Float64)
+}
+
+// Floats returns Value as a float slice. If it is not a float slice, it returns nil.
+func (v Value) Floats() (f64s []float64) {
+	return values[float64](v, reflect.Float32, reflect.Float64)
+}
+
+// Bool returns Value as a boolean. If it is not a boolean, it returns false.
+func (v Value) Bool() bool {
+	return value[bool](v, reflect.Bool)
+}
+
+// Bools returns Value as a boolean slice. If it is not a boolean slice, it returns nil.
+func (v Value) Bools() (bools []bool) {
+	return values[bool](v, reflect.Bool)
+}
+
+// String returns Value as a string. If it is not a string, it returns an empty string.
+func (v Value) String() string {
+	return value[string](v, reflect.String)
+}
+
+// Strings returns Value as a string slice. If it is not a string slice, it returns nil.
+func (v Value) Strings() (strings []string) {
+	return values[string](v, reflect.String)
+}