pdf file text reading and searching

I want to read text from pdf file and search text into pdf file.

here the link that I know.

none of this help me out.

Getting text position while parsing pdf with Quartz 2D

HIghlighting the text in PDF document iPhone xcode

https://developer.apple.com/library/archive/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_pdf_scan/dq_pdf_scan.html#//apple_ref/doc/uid/TP30001066-CH220-CJBDCGCB

Reading PDF files 开发者_开发知识库as string through iPhone application

Look at PDFKitten, it's a good start - it does all the glyph width analysis for you, but it's not perfect either.