Merge PDF files on iOS

I’ve made a little refactor on Jonathan’s code to join any PDF file of any size:

+ (NSString *)joinPDF:(NSArray *)listOfPaths {
    // File paths
    NSString *fileName = @"ALL.pdf";
    NSString *pdfPathOutput = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:fileName];

    CFURLRef pdfURLOutput = (  CFURLRef)CFBridgingRetain([NSURL fileURLWithPath:pdfPathOutput]);

    NSInteger numberOfPages = 0;
    // Create the output context
    CGContextRef writeContext = CGPDFContextCreateWithURL(pdfURLOutput, NULL, NULL);

    for (NSString *source in listOfPaths) {
        CFURLRef pdfURL = (  CFURLRef)CFBridgingRetain([[NSURL alloc] initFileURLWithPath:source]);

        //file ref
        CGPDFDocumentRef pdfRef = CGPDFDocumentCreateWithURL((CFURLRef) pdfURL);
        numberOfPages = CGPDFDocumentGetNumberOfPages(pdfRef);

        // Loop variables
        CGPDFPageRef page;
        CGRect mediaBox;

        // Read the first PDF and generate the output pages
        DLog(@"GENERATING PAGES FROM PDF 1 (%@)...", source);
        for (int i=1; i<=numberOfPages; i++) {
            page = CGPDFDocumentGetPage(pdfRef, i);
            mediaBox = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
            CGContextBeginPage(writeContext, &mediaBox);
            CGContextDrawPDFPage(writeContext, page);
            CGContextEndPage(writeContext);
        }

        CGPDFDocumentRelease(pdfRef);
        CFRelease(pdfURL);
    }
    CFRelease(pdfURLOutput);

    // Finalize the output file
    CGPDFContextClose(writeContext);
    CGContextRelease(writeContext);

    return pdfPathOutput;
}

Hope that helps