fix wrong git ignore

internal/pdf/core/utils.go

@@ -0,0 +1,172 @@
+package core
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+
+	"gitea.tecamino.com/paadi/pdfmerge/internal/pdf/common"
+)
+
+// Check slice range to make sure within bounds for accessing:
+//
+//	slice[a:b] where sliceLen=len(slice).
+func checkBounds(sliceLen, a, b int) error {
+	if a < 0 || a > sliceLen {
+		return errors.New("slice index a out of bounds")
+	}
+	if b < a {
+		return errors.New("invalid slice index b < a")
+	}
+	if b > sliceLen {
+		return errors.New("slice index b out of bounds")
+	}
+
+	return nil
+}
+
+// Inspect analyzes the document object structure.
+func (parser *PdfParser) Inspect() (map[string]int, error) {
+	return parser.inspect()
+}
+
+// GetObjectNums returns a sorted list of object numbers of the PDF objects in the file.
+func (parser *PdfParser) GetObjectNums() []int {
+	objNums := []int{}
+	for _, x := range parser.xrefs {
+		objNums = append(objNums, x.objectNumber)
+	}
+
+	// Sort the object numbers to give consistent ordering of PDF objects in output.
+	// Needed since parser.xrefs is a map.
+	sort.Ints(objNums)
+
+	return objNums
+}
+
+/*
+ * Inspect object types.
+ * Go through all objects in the cross ref table and detect the types.
+ * Mostly for debugging purposes and inspecting odd PDF files.
+ */
+func (parser *PdfParser) inspect() (map[string]int, error) {
+	common.Log.Trace("--------INSPECT ----------")
+	common.Log.Trace("Xref table:")
+
+	objTypes := map[string]int{}
+	objCount := 0
+	failedCount := 0
+
+	keys := []int{}
+	for k := range parser.xrefs {
+		keys = append(keys, k)
+	}
+	sort.Ints(keys)
+
+	i := 0
+	for _, k := range keys {
+		xref := parser.xrefs[k]
+		if xref.objectNumber == 0 {
+			continue
+		}
+		objCount++
+		common.Log.Trace("==========")
+		common.Log.Trace("Looking up object number: %d", xref.objectNumber)
+		o, err := parser.LookupByNumber(xref.objectNumber)
+		if err != nil {
+			common.Log.Trace("error: Fail to lookup obj %d (%s)", xref.objectNumber, err)
+			failedCount++
+			continue
+		}
+
+		common.Log.Trace("obj: %s", o)
+
+		iobj, isIndirect := o.(*PdfIndirectObject)
+		if isIndirect {
+			common.Log.Trace("IND OOBJ %d: %s", xref.objectNumber, iobj)
+			dict, isDict := iobj.PdfObject.(*PdfObjectDictionary)
+			if isDict {
+				// Check if has Type parameter.
+				if ot, has := dict.Get("Type").(*PdfObjectName); has {
+					otype := string(*ot)
+					common.Log.Trace("---> Obj type: %s", otype)
+					_, isDefined := objTypes[otype]
+					if isDefined {
+						objTypes[otype]++
+					} else {
+						objTypes[otype] = 1
+					}
+				} else if ot, has := dict.Get("Subtype").(*PdfObjectName); has {
+					// Check if subtype
+					otype := string(*ot)
+					common.Log.Trace("---> Obj subtype: %s", otype)
+					_, isDefined := objTypes[otype]
+					if isDefined {
+						objTypes[otype]++
+					} else {
+						objTypes[otype] = 1
+					}
+				}
+				if val, has := dict.Get("S").(*PdfObjectName); has && *val == "JavaScript" {
+					// Check if Javascript.
+					_, isDefined := objTypes["JavaScript"]
+					if isDefined {
+						objTypes["JavaScript"]++
+					} else {
+						objTypes["JavaScript"] = 1
+					}
+				}
+
+			}
+		} else if sobj, isStream := o.(*PdfObjectStream); isStream {
+			if otype, ok := sobj.PdfObjectDictionary.Get("Type").(*PdfObjectName); ok {
+				common.Log.Trace("--> Stream object type: %s", *otype)
+				k := string(*otype)
+				objTypes[k]++
+			}
+		} else { // Direct.
+			dict, isDict := o.(*PdfObjectDictionary)
+			if isDict {
+				ot, isName := dict.Get("Type").(*PdfObjectName)
+				if isName {
+					otype := string(*ot)
+					common.Log.Trace("--- obj type %s", otype)
+					objTypes[otype]++
+				}
+			}
+			common.Log.Trace("DIRECT OBJ %d: %s", xref.objectNumber, o)
+		}
+
+		i++
+	}
+	common.Log.Trace("--------EOF INSPECT ----------")
+	common.Log.Trace("=======")
+	common.Log.Trace("Object count: %d", objCount)
+	common.Log.Trace("Failed lookup: %d", failedCount)
+	for t, c := range objTypes {
+		common.Log.Trace("%s: %d", t, c)
+	}
+	common.Log.Trace("=======")
+
+	if len(parser.xrefs) < 1 {
+		common.Log.Debug("error: This document is invalid (xref table missing!)")
+		return nil, fmt.Errorf("invalid document (xref table missing)")
+	}
+
+	fontObjs, ok := objTypes["Font"]
+	if !ok || fontObjs < 2 {
+		common.Log.Trace("This document is probably scanned!")
+	} else {
+		common.Log.Trace("This document is valid for extraction!")
+	}
+
+	return objTypes, nil
+}
+
+func absInt(x int) int {
+	if x < 0 {
+		return -x
+	} else {
+		return x
+	}
+}