Parsing file with lots of dictionaries is extremely slow #775
Description
I experienced this with a PDF that is a 9-page export of CAD drawings containing lots of small lines and numbers (created using "PDFTron PDFNet, V6.40292"). Unfortunately I can't share the document.
Tested with latest master (b89d7b1) and the test script below.
package main
import (
"log"
"os"
"github.com/pdfcpu/pdfcpu/pkg/pdfcpu"
"github.com/pdfcpu/pdfcpu/pkg/pdfcpu/model"
)
func main() {
log.SetFlags(log.Flags() | log.Lmicroseconds)
fp, err := os.Open("slow-parse.pdf")
if err != nil {
log.Fatal(err)
}
defer fp.Close()
conf := model.NewDefaultConfiguration()
log.Printf("Parsing ...")
pdf, err := pdfcpu.Read(fp, conf)
if err != nil {
log.Fatal(err)
}
log.Printf("Done")
if err := pdf.EnsurePageCount(); err != nil {
log.Fatal(err)
}
log.Printf("Parsed %d pages", pdf.PageCount)
}Parsing doesn't stop (I killed it after 5 minutes taking 100% CPU). I have a patch ready takes improves parsing this file to below 4 seconds.