fix wrong git ignore

internal/pdf/contentstream/contentstream.go

@@ -0,0 +1,197 @@
+package contentstream
+
+import (
+	"bytes"
+	"fmt"
+
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/core"
+)
+
+type ContentStreamOperation struct {
+	Params  []core.PdfObject
+	Operand string
+}
+
+type ContentStreamOperations []*ContentStreamOperation
+
+// Check if the content stream operations are fully wrapped (within q ... Q)
+func (s *ContentStreamOperations) isWrapped() bool {
+	if len(*s) < 2 {
+		return false
+	}
+
+	depth := 0
+	for _, op := range *s {
+		switch op.Operand {
+		case "q":
+			depth++
+		case "Q":
+			depth--
+		default:
+			if depth < 1 {
+				return false
+			}
+		}
+	}
+
+	// Should end at depth == 0
+	return depth == 0
+}
+
+// Wrap entire contents within q ... Q.  If unbalanced, then adds extra Qs at the end.
+// Only does if needed. Ensures that when adding new content, one start with all states
+// in the default condition.
+func (s *ContentStreamOperations) WrapIfNeeded() *ContentStreamOperations {
+	if len(*s) == 0 {
+		// No need to wrap if empty.
+		return s
+	}
+	if s.isWrapped() {
+		return s
+	}
+
+	*s = append([]*ContentStreamOperation{{Operand: "q"}}, *s...)
+
+	depth := 0
+	for _, op := range *s {
+		switch op.Operand {
+		case "q":
+			depth++
+		case "Q":
+			depth--
+		}
+	}
+
+	for depth > 0 {
+		*s = append(*s, &ContentStreamOperation{Operand: "Q"})
+		depth--
+	}
+
+	return s
+}
+
+// Convert a set of content stream operations to a content stream byte presentation, i.e. the kind that can be
+// stored as a PDF stream or string format.
+func (s *ContentStreamOperations) Bytes() []byte {
+	var buf bytes.Buffer
+
+	for _, op := range *s {
+		if op == nil {
+			continue
+		}
+
+		if op.Operand == "BI" {
+			// Inline image requires special handling.
+			buf.WriteString(op.Operand + "\n")
+			buf.WriteString(op.Params[0].DefaultWriteString())
+
+		} else {
+			// Default handler.
+			for _, param := range op.Params {
+				buf.WriteString(param.DefaultWriteString())
+				buf.WriteString(" ")
+
+			}
+
+			buf.WriteString(op.Operand + "\n")
+		}
+	}
+
+	return buf.Bytes()
+}
+
+// ExtractText parses and extracts all text data in content streams and returns as a string.
+// Does not take into account Encoding table, the output is simply the character codes.
+//
+// Deprecated: More advanced text extraction is offered in package extractor with character encoding support.
+func (s *ContentStreamParser) ExtractText() (string, error) {
+	operations, err := s.Parse()
+	if err != nil {
+		return "", err
+	}
+	inText := false
+	xPos, yPos := float64(-1), float64(-1)
+	txt := ""
+	for _, op := range *operations {
+		switch op.Operand {
+		case "BT":
+			inText = true
+		case "ET":
+			inText = false
+		}
+
+		if op.Operand == "Td" || op.Operand == "TD" || op.Operand == "T*" {
+			// Move to next line...
+			txt += "\n"
+		}
+		if op.Operand == "Tm" {
+			if len(op.Params) != 6 {
+				continue
+			}
+			xfloat, ok := op.Params[4].(*core.PdfObjectFloat)
+			if !ok {
+				xint, ok := op.Params[4].(*core.PdfObjectInteger)
+				if !ok {
+					continue
+				}
+				xfloat = core.MakeFloat(float64(*xint))
+			}
+			yfloat, ok := op.Params[5].(*core.PdfObjectFloat)
+			if !ok {
+				yint, ok := op.Params[5].(*core.PdfObjectInteger)
+				if !ok {
+					continue
+				}
+				yfloat = core.MakeFloat(float64(*yint))
+			}
+			if yPos == -1 {
+				yPos = float64(*yfloat)
+			} else if yPos > float64(*yfloat) {
+				txt += "\n"
+				xPos = float64(*xfloat)
+				yPos = float64(*yfloat)
+				continue
+			}
+			if xPos == -1 {
+				xPos = float64(*xfloat)
+			} else if xPos < float64(*xfloat) {
+				txt += "\t"
+				xPos = float64(*xfloat)
+			}
+		}
+		if inText && op.Operand == "TJ" {
+			if len(op.Params) < 1 {
+				continue
+			}
+			paramList, ok := op.Params[0].(*core.PdfObjectArray)
+			if !ok {
+				return "", fmt.Errorf("invalid parameter type, no array (%T)", op.Params[0])
+			}
+			for _, obj := range *paramList {
+				switch v := obj.(type) {
+				case *core.PdfObjectString:
+					txt += string(*v)
+				case *core.PdfObjectFloat:
+					if *v < -100 {
+						txt += " "
+					}
+				case *core.PdfObjectInteger:
+					if *v < -100 {
+						txt += " "
+					}
+				}
+			}
+		} else if inText && op.Operand == "Tj" {
+			if len(op.Params) < 1 {
+				continue
+			}
+			param, ok := op.Params[0].(*core.PdfObjectString)
+			if !ok {
+				return "", fmt.Errorf("invalid parameter type, not string (%T)", op.Params[0])
+			}
+			txt += string(*param)
+		}
+	}
+
+	return txt, nil
+}