chore: vendor go dependencies

1 files changed, 436 insertions, 0 deletions

diff --git a/vendor/github.com/ebitengine/purego/func.go b/vendor/github.com/ebitengine/purego/func.go
new file mode 100644
index 0000000..a8a3d62
--- /dev/null
+++ b/vendor/github.com/ebitengine/purego/func.go
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
+
+//go:build darwin || freebsd || linux || windows
+
+package purego
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+	"runtime"
+	"unsafe"
+
+	"github.com/ebitengine/purego/internal/strings"
+)
+
+// RegisterLibFunc is a wrapper around RegisterFunc that uses the C function returned from Dlsym(handle, name).
+// It panics if it can't find the name symbol.
+func RegisterLibFunc(fptr interface{}, handle uintptr, name string) {
+	sym, err := loadSymbol(handle, name)
+	if err != nil {
+		panic(err)
+	}
+	RegisterFunc(fptr, sym)
+}
+
+// RegisterFunc takes a pointer to a Go function representing the calling convention of the C function.
+// fptr will be set to a function that when called will call the C function given by cfn with the
+// parameters passed in the correct registers and stack.
+//
+// A panic is produced if the type is not a function pointer or if the function returns more than 1 value.
+//
+// These conversions describe how a Go type in the fptr will be used to call
+// the C function. It is important to note that there is no way to verify that fptr
+// matches the C function. This also holds true for struct types where the padding
+// needs to be ensured to match that of C; RegisterFunc does not verify this.
+//
+// # Type Conversions (Go <=> C)
+//
+//	string <=> char*
+//	bool <=> _Bool
+//	uintptr <=> uintptr_t
+//	uint <=> uint32_t or uint64_t
+//	uint8 <=> uint8_t
+//	uint16 <=> uint16_t
+//	uint32 <=> uint32_t
+//	uint64 <=> uint64_t
+//	int <=> int32_t or int64_t
+//	int8 <=> int8_t
+//	int16 <=> int16_t
+//	int32 <=> int32_t
+//	int64 <=> int64_t
+//	float32 <=> float
+//	float64 <=> double
+//	struct <=> struct (WIP - darwin only)
+//	func <=> C function
+//	unsafe.Pointer, *T <=> void*
+//	[]T => void*
+//
+// There is a special case when the last argument of fptr is a variadic interface (or []interface}
+// it will be expanded into a call to the C function as if it had the arguments in that slice.
+// This means that using arg ...interface{} is like a cast to the function with the arguments inside arg.
+// This is not the same as C variadic.
+//
+// # Memory
+//
+// In general it is not possible for purego to guarantee the lifetimes of objects returned or received from
+// calling functions using RegisterFunc. For arguments to a C function it is important that the C function doesn't
+// hold onto a reference to Go memory. This is the same as the [Cgo rules].
+//
+// However, there are some special cases. When passing a string as an argument if the string does not end in a null
+// terminated byte (\x00) then the string will be copied into memory maintained by purego. The memory is only valid for
+// that specific call. Therefore, if the C code keeps a reference to that string it may become invalid at some
+// undefined time. However, if the string does already contain a null-terminated byte then no copy is done.
+// It is then the responsibility of the caller to ensure the string stays alive as long as it's needed in C memory.
+// This can be done using runtime.KeepAlive or allocating the string in C memory using malloc. When a C function
+// returns a null-terminated pointer to char a Go string can be used. Purego will allocate a new string in Go memory
+// and copy the data over. This string will be garbage collected whenever Go decides it's no longer referenced.
+// This C created string will not be freed by purego. If the pointer to char is not null-terminated or must continue
+// to point to C memory (because it's a buffer for example) then use a pointer to byte and then convert that to a slice
+// using unsafe.Slice. Doing this means that it becomes the responsibility of the caller to care about the lifetime
+// of the pointer
+//
+// # Structs
+//
+// Purego can handle the most common structs that have fields of builtin types like int8, uint16, float32, etc. However,
+// it does not support aligning fields properly. It is therefore the responsibility of the caller to ensure
+// that all padding is added to the Go struct to match the C one. See `BoolStructFn` in struct_test.go for an example.
+//
+// # Example
+//
+// All functions below call this C function:
+//
+//	char *foo(char *str);
+//
+//	// Let purego convert types
+//	var foo func(s string) string
+//	goString := foo("copied")
+//	// Go will garbage collect this string
+//
+//	// Manually, handle allocations
+//	var foo2 func(b string) *byte
+//	mustFree := foo2("not copied\x00")
+//	defer free(mustFree)
+//
+// [Cgo rules]: https://pkg.go.dev/cmd/cgo#hdr-Go_references_to_C
+func RegisterFunc(fptr interface{}, cfn uintptr) {
+	fn := reflect.ValueOf(fptr).Elem()
+	ty := fn.Type()
+	if ty.Kind() != reflect.Func {
+		panic("purego: fptr must be a function pointer")
+	}
+	if ty.NumOut() > 1 {
+		panic("purego: function can only return zero or one values")
+	}
+	if cfn == 0 {
+		panic("purego: cfn is nil")
+	}
+	if ty.NumOut() == 1 && (ty.Out(0).Kind() == reflect.Float32 || ty.Out(0).Kind() == reflect.Float64) &&
+		runtime.GOARCH != "arm64" && runtime.GOARCH != "amd64" {
+		panic("purego: float returns are not supported")
+	}
+	{
+		// this code checks how many registers and stack this function will use
+		// to avoid crashing with too many arguments
+		var ints int
+		var floats int
+		var stack int
+		for i := 0; i < ty.NumIn(); i++ {
+			arg := ty.In(i)
+			switch arg.Kind() {
+			case reflect.Func:
+				// This only does preliminary testing to ensure the CDecl argument
+				// is the first argument. Full testing is done when the callback is actually
+				// created in NewCallback.
+				for j := 0; j < arg.NumIn(); j++ {
+					in := arg.In(j)
+					if !in.AssignableTo(reflect.TypeOf(CDecl{})) {
+						continue
+					}
+					if j != 0 {
+						panic("purego: CDecl must be the first argument")
+					}
+				}
+			case reflect.String, reflect.Uintptr, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+				reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Ptr, reflect.UnsafePointer,
+				reflect.Slice, reflect.Bool:
+				if ints < numOfIntegerRegisters() {
+					ints++
+				} else {
+					stack++
+				}
+			case reflect.Float32, reflect.Float64:
+				const is32bit = unsafe.Sizeof(uintptr(0)) == 4
+				if is32bit {
+					panic("purego: floats only supported on 64bit platforms")
+				}
+				if floats < numOfFloats {
+					floats++
+				} else {
+					stack++
+				}
+			case reflect.Struct:
+				if runtime.GOOS != "darwin" || (runtime.GOARCH != "amd64" && runtime.GOARCH != "arm64") {
+					panic("purego: struct arguments are only supported on darwin amd64 & arm64")
+				}
+				if arg.Size() == 0 {
+					continue
+				}
+				addInt := func(u uintptr) {
+					ints++
+				}
+				addFloat := func(u uintptr) {
+					floats++
+				}
+				addStack := func(u uintptr) {
+					stack++
+				}
+				_ = addStruct(reflect.New(arg).Elem(), &ints, &floats, &stack, addInt, addFloat, addStack, nil)
+			default:
+				panic("purego: unsupported kind " + arg.Kind().String())
+			}
+		}
+		if ty.NumOut() == 1 && ty.Out(0).Kind() == reflect.Struct {
+			if runtime.GOOS != "darwin" {
+				panic("purego: struct return values only supported on darwin arm64 & amd64")
+			}
+			outType := ty.Out(0)
+			checkStructFieldsSupported(outType)
+			if runtime.GOARCH == "amd64" && outType.Size() > maxRegAllocStructSize {
+				// on amd64 if struct is bigger than 16 bytes allocate the return struct
+				// and pass it in as a hidden first argument.
+				ints++
+			}
+		}
+		sizeOfStack := maxArgs - numOfIntegerRegisters()
+		if stack > sizeOfStack {
+			panic("purego: too many arguments")
+		}
+	}
+	v := reflect.MakeFunc(ty, func(args []reflect.Value) (results []reflect.Value) {
+		if len(args) > 0 {
+			if variadic, ok := args[len(args)-1].Interface().([]interface{}); ok {
+				// subtract one from args bc the last argument in args is []interface{}
+				// which we are currently expanding
+				tmp := make([]reflect.Value, len(args)-1+len(variadic))
+				n := copy(tmp, args[:len(args)-1])
+				for i, v := range variadic {
+					tmp[n+i] = reflect.ValueOf(v)
+				}
+				args = tmp
+			}
+		}
+		var sysargs [maxArgs]uintptr
+		stack := sysargs[numOfIntegerRegisters():]
+		var floats [numOfFloats]uintptr
+		var numInts int
+		var numFloats int
+		var numStack int
+		var addStack, addInt, addFloat func(x uintptr)
+		if runtime.GOARCH == "arm64" || runtime.GOOS != "windows" {
+			// Windows arm64 uses the same calling convention as macOS and Linux
+			addStack = func(x uintptr) {
+				stack[numStack] = x
+				numStack++
+			}
+			addInt = func(x uintptr) {
+				if numInts >= numOfIntegerRegisters() {
+					addStack(x)
+				} else {
+					sysargs[numInts] = x
+					numInts++
+				}
+			}
+			addFloat = func(x uintptr) {
+				if numFloats < len(floats) {
+					floats[numFloats] = x
+					numFloats++
+				} else {
+					addStack(x)
+				}
+			}
+		} else {
+			// On Windows amd64 the arguments are passed in the numbered registered.
+			// So the first int is in the first integer register and the first float
+			// is in the second floating register if there is already a first int.
+			// This is in contrast to how macOS and Linux pass arguments which
+			// tries to use as many registers as possible in the calling convention.
+			addStack = func(x uintptr) {
+				sysargs[numStack] = x
+				numStack++
+			}
+			addInt = addStack
+			addFloat = addStack
+		}
+
+		var keepAlive []interface{}
+		defer func() {
+			runtime.KeepAlive(keepAlive)
+			runtime.KeepAlive(args)
+		}()
+		var syscall syscall15Args
+		if ty.NumOut() == 1 && ty.Out(0).Kind() == reflect.Struct {
+			outType := ty.Out(0)
+			if runtime.GOARCH == "amd64" && outType.Size() > maxRegAllocStructSize {
+				val := reflect.New(outType)
+				keepAlive = append(keepAlive, val)
+				addInt(val.Pointer())
+			} else if runtime.GOARCH == "arm64" && outType.Size() > maxRegAllocStructSize {
+				isAllFloats, numFields := isAllSameFloat(outType)
+				if !isAllFloats || numFields > 4 {
+					val := reflect.New(outType)
+					keepAlive = append(keepAlive, val)
+					syscall.arm64_r8 = val.Pointer()
+				}
+			}
+		}
+		for _, v := range args {
+			switch v.Kind() {
+			case reflect.String:
+				ptr := strings.CString(v.String())
+				keepAlive = append(keepAlive, ptr)
+				addInt(uintptr(unsafe.Pointer(ptr)))
+			case reflect.Uintptr, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+				addInt(uintptr(v.Uint()))
+			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+				addInt(uintptr(v.Int()))
+			case reflect.Ptr, reflect.UnsafePointer, reflect.Slice:
+				// There is no need to keepAlive this pointer separately because it is kept alive in the args variable
+				addInt(v.Pointer())
+			case reflect.Func:
+				addInt(NewCallback(v.Interface()))
+			case reflect.Bool:
+				if v.Bool() {
+					addInt(1)
+				} else {
+					addInt(0)
+				}
+			case reflect.Float32:
+				addFloat(uintptr(math.Float32bits(float32(v.Float()))))
+			case reflect.Float64:
+				addFloat(uintptr(math.Float64bits(v.Float())))
+			case reflect.Struct:
+				keepAlive = addStruct(v, &numInts, &numFloats, &numStack, addInt, addFloat, addStack, keepAlive)
+			default:
+				panic("purego: unsupported kind: " + v.Kind().String())
+			}
+		}
+		if runtime.GOARCH == "arm64" || runtime.GOOS != "windows" {
+			// Use the normal arm64 calling convention even on Windows
+			syscall = syscall15Args{
+				cfn,
+				sysargs[0], sysargs[1], sysargs[2], sysargs[3], sysargs[4], sysargs[5],
+				sysargs[6], sysargs[7], sysargs[8], sysargs[9], sysargs[10], sysargs[11],
+				sysargs[12], sysargs[13], sysargs[14],
+				floats[0], floats[1], floats[2], floats[3], floats[4], floats[5], floats[6], floats[7],
+				syscall.arm64_r8,
+			}
+			runtime_cgocall(syscall15XABI0, unsafe.Pointer(&syscall))
+		} else {
+			// This is a fallback for Windows amd64, 386, and arm. Note this may not support floats
+			syscall.a1, syscall.a2, _ = syscall_syscall15X(cfn, sysargs[0], sysargs[1], sysargs[2], sysargs[3], sysargs[4],
+				sysargs[5], sysargs[6], sysargs[7], sysargs[8], sysargs[9], sysargs[10], sysargs[11],
+				sysargs[12], sysargs[13], sysargs[14])
+			syscall.f1 = syscall.a2 // on amd64 a2 stores the float return. On 32bit platforms floats aren't support
+		}
+		if ty.NumOut() == 0 {
+			return nil
+		}
+		outType := ty.Out(0)
+		v := reflect.New(outType).Elem()
+		switch outType.Kind() {
+		case reflect.Uintptr, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			v.SetUint(uint64(syscall.a1))
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			v.SetInt(int64(syscall.a1))
+		case reflect.Bool:
+			v.SetBool(byte(syscall.a1) != 0)
+		case reflect.UnsafePointer:
+			// We take the address and then dereference it to trick go vet from creating a possible miss-use of unsafe.Pointer
+			v.SetPointer(*(*unsafe.Pointer)(unsafe.Pointer(&syscall.a1)))
+		case reflect.Ptr:
+			v = reflect.NewAt(outType, unsafe.Pointer(&syscall.a1)).Elem()
+		case reflect.Func:
+			// wrap this C function in a nicely typed Go function
+			v = reflect.New(outType)
+			RegisterFunc(v.Interface(), syscall.a1)
+		case reflect.String:
+			v.SetString(strings.GoString(syscall.a1))
+		case reflect.Float32:
+			// NOTE: syscall.r2 is only the floating return value on 64bit platforms.
+			// On 32bit platforms syscall.r2 is the upper part of a 64bit return.
+			v.SetFloat(float64(math.Float32frombits(uint32(syscall.f1))))
+		case reflect.Float64:
+			// NOTE: syscall.r2 is only the floating return value on 64bit platforms.
+			// On 32bit platforms syscall.r2 is the upper part of a 64bit return.
+			v.SetFloat(math.Float64frombits(uint64(syscall.f1)))
+		case reflect.Struct:
+			v = getStruct(outType, syscall)
+		default:
+			panic("purego: unsupported return kind: " + outType.Kind().String())
+		}
+		return []reflect.Value{v}
+	})
+	fn.Set(v)
+}
+
+// maxRegAllocStructSize is the biggest a struct can be while still fitting in registers.
+// if it is bigger than this than enough space must be allocated on the heap and then passed into
+// the function as the first parameter on amd64 or in R8 on arm64.
+//
+// If you change this make sure to update it in objc_runtime_darwin.go
+const maxRegAllocStructSize = 16
+
+func isAllSameFloat(ty reflect.Type) (allFloats bool, numFields int) {
+	allFloats = true
+	root := ty.Field(0).Type
+	for root.Kind() == reflect.Struct {
+		root = root.Field(0).Type
+	}
+	first := root.Kind()
+	if first != reflect.Float32 && first != reflect.Float64 {
+		allFloats = false
+	}
+	for i := 0; i < ty.NumField(); i++ {
+		f := ty.Field(i).Type
+		if f.Kind() == reflect.Struct {
+			var structNumFields int
+			allFloats, structNumFields = isAllSameFloat(f)
+			numFields += structNumFields
+			continue
+		}
+		numFields++
+		if f.Kind() != first {
+			allFloats = false
+		}
+	}
+	return allFloats, numFields
+}
+
+func checkStructFieldsSupported(ty reflect.Type) {
+	for i := 0; i < ty.NumField(); i++ {
+		f := ty.Field(i).Type
+		if f.Kind() == reflect.Array {
+			f = f.Elem()
+		} else if f.Kind() == reflect.Struct {
+			checkStructFieldsSupported(f)
+			continue
+		}
+		switch f.Kind() {
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+			reflect.Uintptr, reflect.Ptr, reflect.UnsafePointer, reflect.Float64, reflect.Float32:
+		default:
+			panic(fmt.Sprintf("purego: struct field type %s is not supported", f))
+		}
+	}
+}
+
+func roundUpTo8(val uintptr) uintptr {
+	return (val + 7) &^ 7
+}
+
+func numOfIntegerRegisters() int {
+	switch runtime.GOARCH {
+	case "arm64":
+		return 8
+	case "amd64":
+		return 6
+	default:
+		// since this platform isn't supported and can therefore only access
+		// integer registers it is fine to return the maxArgs
+		return maxArgs
+	}
+}