Fix PS processing of dup operand. Fixes #98.

Added test cases to verify.

pdf/ps/exec.go

@@ -9,6 +9,8 @@ package ps
 
 import (
 	"fmt"
+
+	"github.com/unidoc/unidoc/common"
 )
 
 // A PSExecutor has its own execution stack and is used to executre a PS routine (program).
@@ -52,6 +54,7 @@ func (this *PSExecutor) Execute(objects []PSObject) ([]PSObject, error) {
 
 	err := this.program.Exec(this.Stack)
 	if err != nil {
+		common.Log.Debug("Exec failed: %v", err)
 		return nil, err
 	}
 

pdf/ps/object.go

@@ -587,6 +587,12 @@ func (this *PSOperand) Dup(stack *PSStack) error {
 		return err
 	}
 
+	// Push it back.
+	err = stack.Push(obj)
+	if err != nil {
+		return err
+	}
+	// Push the duplicate.
 	err = stack.Push(obj.Duplicate())
 	return err
 }

pdf/ps/parser_test.go

@@ -16,7 +16,8 @@ import (
 )
 
 func init() {
-	common.SetLogger(common.ConsoleLogger{})
+	common.SetLogger(common.NewConsoleLogger(common.LogLevelDebug))
+	//common.SetLogger(common.NewConsoleLogger(common.LogLevelTrace))
 }
 
 func makeReaderForText(txt string) *bufio.Reader {
@@ -270,6 +271,8 @@ func TestFunctionOperations(t *testing.T) {
 
 func TestVariousCases(t *testing.T) {
 	testcases := []ComplexTestEntry{
+		// dup
+		{progText: "{ 99 dup }", expected: "[ int:99 int:99 ]"},
 		// ceiling
 		{progText: "{ 3.2 ceiling }", expected: "[ real:4.00000 ]"},
 		{progText: "{ -4.8 ceiling }", expected: "[ real:-4.00000 ]"},
@@ -405,3 +408,24 @@ func TestVariousCases(t *testing.T) {
 		}
 	}
 }
+
+func TestTintTransform1(t *testing.T) {
+	testcases := []ComplexTestEntry{
+		// from corpus epson_pages3_color_pages1.pdf.
+		{progText: "{ 0.0000 dup 0 mul exch dup 0 mul exch dup 0 mul exch 1 mul }", expected: "[ real:0.00000 real:0.00000 real:0.00000 real:0.00000 ]"},
+	}
+
+	for _, testcase := range testcases {
+		stack, err := quickTest(testcase.progText)
+		if err != nil {
+			t.Errorf("Error: %v", err)
+			return
+		}
+
+		// Maybe not the most robust test (comparing the strings), but should do.
+		if stack.DebugString() != testcase.expected {
+			t.Errorf("Wrong result: '%s' != '%s'", stack.DebugString(), testcase.expected)
+			return
+		}
+	}
+}