feat(MemcpyEnterScope): enters a new scope for the memory copy operat…

…on with a specified length (#372)

* feat(MemcpyEnterScope): enters a new scope for the memory copy operation with a specified length

* fix: addressing review comments

* adding unit test for memcpy hint

* fix lint issue plus and rename hint code to memcpyEnterScopeCode

* rename hint to newMemcpyEnterScopeHint

* fix: memcpy hint as new hint

* fix order of codes

pkg/hintrunner/zero/hintcode.go

@@ -84,7 +84,8 @@ const (
 	// ------ Dictionaries hints related code ------
 
 	// ------ Other hints related code ------
-	allocSegmentCode string = "memory[ap] = segments.add()"
-	vmEnterScopeCode string = "vm_enter_scope()"
-	vmExitScopeCode  string = "vm_exit_scope()"
+	allocSegmentCode     string = "memory[ap] = segments.add()"
+	memcpyEnterScopeCode string = "vm_enter_scope({'n': ids.len})"
+	vmEnterScopeCode     string = "vm_enter_scope()"
+	vmExitScopeCode      string = "vm_exit_scope()"
 )

pkg/hintrunner/zero/zerohint.go

@@ -147,6 +147,8 @@ func GetHintFromCode(program *zero.ZeroProgram, rawHint zero.Hint, hintPC uint64
 		return createAllocSegmentHinter(resolver)
 	case vmEnterScopeCode:
 		return createVMEnterScopeHinter(resolver)
+	case memcpyEnterScopeCode:
+		return createMemcpyEnterScopeHinter(resolver)
 	case vmExitScopeCode:
 		return createVMExitScopeHinter(resolver)
 	case testAssignCode:

pkg/hintrunner/zero/zerohint_memcpy.go

@@ -20,6 +20,29 @@ func createVMEnterScopeHinter(resolver hintReferenceResolver) (hinter.Hinter, er
 	}, nil
 }
 
+func newMemcpyEnterScopeHint(len hinter.ResOperander) hinter.Hinter {
+	return &GenericZeroHinter{
+		Name: "MemcpyEnterScope",
+		Op: func(vm *VM.VirtualMachine, ctx *hinter.HintRunnerContext) error {
+			//>  vm_enter_scope({'n': ids.len})
+			len, err := hinter.ResolveAsFelt(vm, len)
+			if err != nil {
+				return err
+			}
+			ctx.ScopeManager.EnterScope(map[string]any{"n": len})
+			return nil
+		},
+	}
+}
+
+func createMemcpyEnterScopeHinter(resolver hintReferenceResolver) (hinter.Hinter, error) {
+	len, err := resolver.GetResOperander("len")
+	if err != nil {
+		return nil, err
+	}
+	return newMemcpyEnterScopeHint(len), nil
+}
+
 func createVMExitScopeHinter(resolver hintReferenceResolver) (hinter.Hinter, error) {
 	return &GenericZeroHinter{
 		Name: "VMExitScope",

pkg/hintrunner/zero/zerohint_memcpy_test.go

@@ -0,0 +1,27 @@
+package zero
+
+import (
+	"testing"
+
+	"github.com/NethermindEth/cairo-vm-go/pkg/hintrunner/hinter"
+)
+
+func TestZeroHintMemcpy(t *testing.T) {
+
+	runHinterTests(t, map[string][]hintTestCase{
+		"MemcpyEnterScope": {
+			{
+				operanders: []*hintOperander{
+					{Name: "len", Kind: apRelative, Value: feltUint64(1)},
+				},
+				ctxInit: func(ctx *hinter.HintRunnerContext) {
+					hinter.InitializeScopeManager(ctx, map[string]any{})
+				},
+				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
+					return newMemcpyEnterScopeHint(ctx.operanders["len"])
+				},
+				check: varValueInScopeEquals("n", feltUint64(1)),
+			},
+		},
+	})
+}