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//
// Copyright (c) 2021, Přemysl Eric Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// extfs-pdf is an external VFS plugin for Midnight Commander.
// More serious image extractors should rewrite this to use pdfimages(1).
package main
import (
"flag"
"fmt"
"os"
"time"
"janouch.name/pdf-simple-sign/pdf"
)
func die(status int, format string, args ...interface{}) {
os.Stderr.WriteString(fmt.Sprintf(format+"\n", args...))
os.Exit(status)
}
func usage() {
die(1, "Usage: %s [-h] COMMAND DOCUMENT [ARG...]", os.Args[0])
}
func streamSuffix(o *pdf.Object) string {
if filter, _ := o.Dict["Filter"]; filter.Kind == pdf.Name {
switch filter.String {
case "JBIG2Decode":
// This is the file extension used by pdfimages(1).
// This is not a complete JBIG2 standalone file.
return "jb2e"
case "JPXDecode":
return "jp2"
case "DCTDecode":
return "jpg"
default:
return filter.String
}
}
return "stream"
}
func list(mtime time.Time, updater *pdf.Updater) {
stamp := mtime.Local().Format("01-02-2006 15:04:05")
for _, o := range updater.ListIndirect() {
object, err := updater.Get(o.N, o.Generation)
size := 0
if err != nil {
fmt.Fprintf(os.Stderr, "%s\n", err)
} else {
// Accidental transformation, retrieving original data is more work.
size = len(object.Serialize())
}
fmt.Printf("-r--r--r-- 1 0 0 %d %s n%dg%d\n",
size, stamp, o.N, o.Generation)
if object.Kind == pdf.Stream {
fmt.Printf("-r--r--r-- 1 0 0 %d %s n%dg%d.%s\n", len(object.Stream),
stamp, o.N, o.Generation, streamSuffix(&object))
}
}
}
func copyout(updater *pdf.Updater, storedFilename, extractTo string) {
var (
n, generation uint
suffix string
)
m, err := fmt.Sscanf(storedFilename, "n%dg%d%s", &n, &generation, &suffix)
if m < 2 {
die(3, "%s: %s", storedFilename, err)
}
object, err := updater.Get(n, generation)
if err != nil {
die(3, "%s: %s", storedFilename, err)
}
content := []byte(object.Serialize())
if suffix != "" {
content = object.Stream
}
if err = os.WriteFile(extractTo, content, 0666); err != nil {
die(3, "%s", err)
}
}
func main() {
flag.Usage = usage
flag.Parse()
if flag.NArg() < 2 {
usage()
}
command, documentPath := flag.Arg(0), flag.Arg(1)
doc, err := os.ReadFile(documentPath)
if err != nil {
die(1, "%s", err)
}
mtime := time.UnixMilli(0)
if info, err := os.Stat(documentPath); err == nil {
mtime = info.ModTime()
}
updater, err := pdf.NewUpdater(doc)
if err != nil {
die(2, "%s", err)
}
switch command {
default:
die(1, "unsupported command: %s", command)
case "list":
if flag.NArg() != 2 {
usage()
} else {
list(mtime, updater)
}
case "copyout":
if flag.NArg() != 4 {
usage()
} else {
copyout(updater, flag.Arg(2), flag.Arg(3))
}
}
}
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