YapDatabase Extensions for Use with Swift

YapDatabaseExtensions

YapDatabaseExtensions is a suite of convenience APIs for working with YapDatabase. If you’re not familiar with YapDatabase, it’s a powerful key value database for iOS and Mac - check it out!

Motivation

While YapDatabase is great, it’s lacking some out of the box convenience and Swift support. In particular, YapDatabase works heavily with AnyObject types, which is fine for Objective-C but means no type fidelity with Swift. Similarly saving value types like structs or enums in YapDatabase is problematic. This framework has evolved through 2015 to tackle these issues.

Value Types

The support for encoding and decoding value types, previously the Saveable and Archiver protocols, has been renamed and moved to their own project. ValueCoding is a dependency of this framework (along with YapDatabase itself). See its README for more info. However, essentially, if you used this project before version 2.1, you’ll need to rename some types - and Xcode should present Fix It options. Saveable is now ValueCoding, its nested type, previously ArchiverType is now Coder, and this type must conform to a protocol, previously Archiver, now CodingType. See how they were all mixed up? Now fixed.

Persistable

This protocol expresses what is required to support reading from and writing to YapDatabase. Objects are referenced inside the database with a key (a String) inside a collection (also a String).

public protocol Identifiable {
    typealias IdentifierType: CustomStringConvertible
    var identifier: IdentifierType { get }
}

public protocol Persistable: Identifiable {
    static var collection: String { get }
    var metadata: MetadataType? { get set }
}

The identifier property allows the type to support an identifier type such as NSUUID or Int.

While not a requirement of YapDatabase, for these extensions, it is required that values of the same type are stored in the same collection - it is a static property.

There is also a YapDB.Index struct which composes the key and collection into a single type. This is used internally for all access methods. Properties defined in an extension on Persistable provide access to key and index.

Metadata

YapDatabase supports storing metadata alongside the primary object. YapDatabaseExtensions supports automatic reading and writing of metadata as an optional property of the Persistable type.

By default, all types which conform to Persistable, will get a MetadataType of Void which is synthesized by default. Therefore if you do not want or need a metadata type, there is nothing to do.

To support a custom metadata type, just add the following to your Persistable type, e.g.:

struct MyCustomValue: Persistable, ValueCoding {
    typealias Coder = MyCustomValueCoder
    static let collection = “MyCustomValues”
    var metadata: MyCustomMetadata? = .None
    let identifier: NSUUID
}

where the type (MyCustomMetadata in the above snippet) implements either NSCoding or ValueCoding.

When creating a new item, set the metadata property before saving the item to the database. YapDatabaseExtensions will then save the metadata inside YapDatabase correctly. There is no need to encode the metadata inside the primary object. When reading objects which have a valid MetadataType, YapDatabaseExtensions will automatically read, decode and set the item’s metadata before returning the item.

Note that previous metadata protocols ObjectMetadataPersistable and ValueMetadataPersistable have been deprecated in favor of Persistable.

“Correct” Type Patterns

Because the generic protocols, ValueCoding and CodingType have self-reflective properties, they must be correctly implemented for the APIs to be available. This means that the equality ValueCoding.Coder.ValueType == Self must be met. The APIs are all composed with this represented in their generic where clauses. This means that if your ValueCoding type is not the ValueType of its Coder, your code will not compile.

Therefore, there are six valid Persistable type patterns as described in the table below:

Item encoding	Metadata encoding	Pattern
NSCoding	Void Metadata	Object
NSCoding	NSCoding	ObjectWithObjectMetadata
NSCoding	ValueCoding	ObjectWithValueMetadata
ValueCoding	Void Metadata	Value
ValueCoding	NSCoding	ValueWithObjectMetadata
ValueCoding	ValueCoding	ValueWithValueMetadata

Extension APIs

YapDatabaseExtensions provides two styles of API. The functional API works on YapDatabase types, YapDatabaseReadTransaction, YapDatabaseReadWriteTransaction and YapDatabaseConnection. The persistable API works on your Persistable types directly, and receives the YapDatabase type as arguments.

Functional API

The following “functional” APIs are available directly on the YapDatabase types.

// Get a YapDatabaseConnection
let connection = db.newConnection()

// Write a single item
connection.write(item) 

// Write an array of items, using one transaction.
connection.write(items)

// Write asynchronously
connection.asyncWrite(item) { print(“did finish writing”) }
connection.asyncWrite(items) { print(“did finish writing”) }

// Create a write transaction block for multiple writes.
connection.write { transaction in
    transaction.write(item)
    transaction.write(items) 
}

// Write many items asynchronously
connection.asyncWrite({ transaction in
    transaction.write(item)
    transaction.write(items) 
}, completion: { print(“did finish writing”) })

For reading:

if let item: Item? = connection.readAtIndex(index) {
  // etc
}

if let meta: Item.MetadataType? = connection.readMetadataAtIndex(index) {
  // etc
}

let items: [Item] = connection.readAtIndexes(indexes)

if let item: Item? = connection.readByKey(index) {
  // etc
}

let items: [Item] = connection.readByKeys(keys)

let all: [Item] = connection.readAll()

connection.read { transaction in
    let a: Item? = transaction.readAtIndex(index)
    let b: Item? = transaction.readByKey(key)
    let c: [Item] = transaction.readAtIndexes(indexes)
    let d: [Item] = transaction.readByKeys(keys)
    let all: [Item] = transaction.readAll()
    let meta: [Item.MetadataType] = transaction.readMetadataAtIndexes(indexes)
}

Persistable API

The APIs all work on single or sequences of Persistable items. To write to the database:

// Use a YapDatabaseReadWriteTransaction.
let written = item.write(transaction)

// Write synchronously using a YapDatabaseConnection.
let written = item.write(connection)

// Write asynchronously using a YapDatabaseConnection.
item.asyncWrite(connection) { written in
    print(“did finishing writing”)
}

// Return an NSOperation which will perform an sync write on a YapDatabaseConnection.
let write: NSOperation = item.write(connection)

Reading items from the database is a little different.

// Read using a YapDB.Index.
if let item = Item.read(transaction).byIndex(index) {
   // etc - item is correct type, no casting required.
}

// Read an array of items from an array of YapDB.Index(s)
let items = Item.read(transaction).atIndexes(indexes)

// Read using a key
if let item = Item.read(transaction).byKey(key) {
   // etc - item is correct type, no casting required.
}

// Read an array of items from an array of String(s)
let items = Item.read(transaction).byKeys(keys)

if let allItems = Item.read(transaction).all() {
   // etc - an array of Item types.
}

// Get the Items which exist for the given keys, and return the [String] keys which are missing.
let (items, missingKeys) = Item.read(transaction).filterExisting(someKeys)

Similarly, to work directly on a YapDatabaseConnection, use the following:

if let item = Item.read(connection).byIndex(index) {
   // etc - item is correct type, no casting required.
}

if let item = Item.read(connection).byKey(key) {
   // etc - item is correct type, no casting required.
}

if let allItems = Item.read(connection).all() {
   // etc - an array of Item types.
}

let (items, missingKeys) = Item.read(connection).filterExisting(someKeys)

Installation

YapDatabaseExtensions is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'YapDatabaseExtensions'

If you don’t want the extensions API on Persistable, integrate the Functional subspec like this:

pod 'YapDatabaseExtensions/Functional’

API Documentation

API documentation is available on CocoaDocs.org.

Developing

To start working in this repository’s YapDatabaseExtensions.xcodeproj, you’ll need to use Carthage to download & build the project’s dependencies, with the commands carthage checkout and carthage build.

Author

Daniel Thorpe, @danthorpe

License

YapDatabaseExtensions is available under the MIT license. See the LICENSE file for more info.

Author: danthorpe
Source Code: https://github.com/danthorpe/YapDatabaseExtensions
License: MIT license

#ios #swift #database 

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Pdf2gerb: Perl Script Converts PDF Files to Gerber format

pdf2gerb

Perl script converts PDF files to Gerber format

Pdf2Gerb generates Gerber 274X photoplotting and Excellon drill files from PDFs of a PCB. Up to three PDFs are used: the top copper layer, the bottom copper layer (for 2-sided PCBs), and an optional silk screen layer. The PDFs can be created directly from any PDF drawing software, or a PDF print driver can be used to capture the Print output if the drawing software does not directly support output to PDF.

The general workflow is as follows:

1. Design the PCB using your favorite CAD or drawing software.
2. Print the top and bottom copper and top silk screen layers to a PDF file.
3. Run Pdf2Gerb on the PDFs to create Gerber and Excellon files.
4. Use a Gerber viewer to double-check the output against the original PCB design.
5. Make adjustments as needed.
6. Submit the files to a PCB manufacturer.

Please note that Pdf2Gerb does NOT perform DRC (Design Rule Checks), as these will vary according to individual PCB manufacturer conventions and capabilities. Also note that Pdf2Gerb is not perfect, so the output files must always be checked before submitting them. As of version 1.6, Pdf2Gerb supports most PCB elements, such as round and square pads, round holes, traces, SMD pads, ground planes, no-fill areas, and panelization. However, because it interprets the graphical output of a Print function, there are limitations in what it can recognize (or there may be bugs).

See docs/Pdf2Gerb.pdf for install/setup, config, usage, and other info.

---

pdf2gerb_cfg.pm

#Pdf2Gerb config settings:
#Put this file in same folder/directory as pdf2gerb.pl itself (global settings),
#or copy to another folder/directory with PDFs if you want PCB-specific settings.
#There is only one user of this file, so we don't need a custom package or namespace.
#NOTE: all constants defined in here will be added to main namespace.
#package pdf2gerb_cfg;

use strict; #trap undef vars (easier debug)
use warnings; #other useful info (easier debug)


##############################################################################################
#configurable settings:
#change values here instead of in main pfg2gerb.pl file

use constant WANT_COLORS => ($^O !~ m/Win/); #ANSI colors no worky on Windows? this must be set < first DebugPrint() call

#just a little warning; set realistic expectations:
#DebugPrint("${\(CYAN)}Pdf2Gerb.pl ${\(VERSION)}, $^O O/S\n${\(YELLOW)}${\(BOLD)}${\(ITALIC)}This is EXPERIMENTAL software.  \nGerber files MAY CONTAIN ERRORS.  Please CHECK them before fabrication!${\(RESET)}", 0); #if WANT_DEBUG

use constant METRIC => FALSE; #set to TRUE for metric units (only affect final numbers in output files, not internal arithmetic)
use constant APERTURE_LIMIT => 0; #34; #max #apertures to use; generate warnings if too many apertures are used (0 to not check)
use constant DRILL_FMT => '2.4'; #'2.3'; #'2.4' is the default for PCB fab; change to '2.3' for CNC

use constant WANT_DEBUG => 0; #10; #level of debug wanted; higher == more, lower == less, 0 == none
use constant GERBER_DEBUG => 0; #level of debug to include in Gerber file; DON'T USE FOR FABRICATION
use constant WANT_STREAMS => FALSE; #TRUE; #save decompressed streams to files (for debug)
use constant WANT_ALLINPUT => FALSE; #TRUE; #save entire input stream (for debug ONLY)

#DebugPrint(sprintf("${\(CYAN)}DEBUG: stdout %d, gerber %d, want streams? %d, all input? %d, O/S: $^O, Perl: $]${\(RESET)}\n", WANT_DEBUG, GERBER_DEBUG, WANT_STREAMS, WANT_ALLINPUT), 1);
#DebugPrint(sprintf("max int = %d, min int = %d\n", MAXINT, MININT), 1); 

#define standard trace and pad sizes to reduce scaling or PDF rendering errors:
#This avoids weird aperture settings and replaces them with more standardized values.
#(I'm not sure how photoplotters handle strange sizes).
#Fewer choices here gives more accurate mapping in the final Gerber files.
#units are in inches
use constant TOOL_SIZES => #add more as desired
(
#round or square pads (> 0) and drills (< 0):
    .010, -.001,  #tiny pads for SMD; dummy drill size (too small for practical use, but needed so StandardTool will use this entry)
    .031, -.014,  #used for vias
    .041, -.020,  #smallest non-filled plated hole
    .051, -.025,
    .056, -.029,  #useful for IC pins
    .070, -.033,
    .075, -.040,  #heavier leads
#    .090, -.043,  #NOTE: 600 dpi is not high enough resolution to reliably distinguish between .043" and .046", so choose 1 of the 2 here
    .100, -.046,
    .115, -.052,
    .130, -.061,
    .140, -.067,
    .150, -.079,
    .175, -.088,
    .190, -.093,
    .200, -.100,
    .220, -.110,
    .160, -.125,  #useful for mounting holes
#some additional pad sizes without holes (repeat a previous hole size if you just want the pad size):
    .090, -.040,  #want a .090 pad option, but use dummy hole size
    .065, -.040, #.065 x .065 rect pad
    .035, -.040, #.035 x .065 rect pad
#traces:
    .001,  #too thin for real traces; use only for board outlines
    .006,  #minimum real trace width; mainly used for text
    .008,  #mainly used for mid-sized text, not traces
    .010,  #minimum recommended trace width for low-current signals
    .012,
    .015,  #moderate low-voltage current
    .020,  #heavier trace for power, ground (even if a lighter one is adequate)
    .025,
    .030,  #heavy-current traces; be careful with these ones!
    .040,
    .050,
    .060,
    .080,
    .100,
    .120,
);
#Areas larger than the values below will be filled with parallel lines:
#This cuts down on the number of aperture sizes used.
#Set to 0 to always use an aperture or drill, regardless of size.
use constant { MAX_APERTURE => max((TOOL_SIZES)) + .004, MAX_DRILL => -min((TOOL_SIZES)) + .004 }; #max aperture and drill sizes (plus a little tolerance)
#DebugPrint(sprintf("using %d standard tool sizes: %s, max aper %.3f, max drill %.3f\n", scalar((TOOL_SIZES)), join(", ", (TOOL_SIZES)), MAX_APERTURE, MAX_DRILL), 1);

#NOTE: Compare the PDF to the original CAD file to check the accuracy of the PDF rendering and parsing!
#for example, the CAD software I used generated the following circles for holes:
#CAD hole size:   parsed PDF diameter:      error:
#  .014                .016                +.002
#  .020                .02267              +.00267
#  .025                .026                +.001
#  .029                .03167              +.00267
#  .033                .036                +.003
#  .040                .04267              +.00267
#This was usually ~ .002" - .003" too big compared to the hole as displayed in the CAD software.
#To compensate for PDF rendering errors (either during CAD Print function or PDF parsing logic), adjust the values below as needed.
#units are pixels; for example, a value of 2.4 at 600 dpi = .0004 inch, 2 at 600 dpi = .0033"
use constant
{
    HOLE_ADJUST => -0.004 * 600, #-2.6, #holes seemed to be slightly oversized (by .002" - .004"), so shrink them a little
    RNDPAD_ADJUST => -0.003 * 600, #-2, #-2.4, #round pads seemed to be slightly oversized, so shrink them a little
    SQRPAD_ADJUST => +0.001 * 600, #+.5, #square pads are sometimes too small by .00067, so bump them up a little
    RECTPAD_ADJUST => 0, #(pixels) rectangular pads seem to be okay? (not tested much)
    TRACE_ADJUST => 0, #(pixels) traces seemed to be okay?
    REDUCE_TOLERANCE => .001, #(inches) allow this much variation when reducing circles and rects
};

#Also, my CAD's Print function or the PDF print driver I used was a little off for circles, so define some additional adjustment values here:
#Values are added to X/Y coordinates; units are pixels; for example, a value of 1 at 600 dpi would be ~= .002 inch
use constant
{
    CIRCLE_ADJUST_MINX => 0,
    CIRCLE_ADJUST_MINY => -0.001 * 600, #-1, #circles were a little too high, so nudge them a little lower
    CIRCLE_ADJUST_MAXX => +0.001 * 600, #+1, #circles were a little too far to the left, so nudge them a little to the right
    CIRCLE_ADJUST_MAXY => 0,
    SUBST_CIRCLE_CLIPRECT => FALSE, #generate circle and substitute for clip rects (to compensate for the way some CAD software draws circles)
    WANT_CLIPRECT => TRUE, #FALSE, #AI doesn't need clip rect at all? should be on normally?
    RECT_COMPLETION => FALSE, #TRUE, #fill in 4th side of rect when 3 sides found
};

#allow .012 clearance around pads for solder mask:
#This value effectively adjusts pad sizes in the TOOL_SIZES list above (only for solder mask layers).
use constant SOLDER_MARGIN => +.012; #units are inches

#line join/cap styles:
use constant
{
    CAP_NONE => 0, #butt (none); line is exact length
    CAP_ROUND => 1, #round cap/join; line overhangs by a semi-circle at either end
    CAP_SQUARE => 2, #square cap/join; line overhangs by a half square on either end
    CAP_OVERRIDE => FALSE, #cap style overrides drawing logic
};
    
#number of elements in each shape type:
use constant
{
    RECT_SHAPELEN => 6, #x0, y0, x1, y1, count, "rect" (start, end corners)
    LINE_SHAPELEN => 6, #x0, y0, x1, y1, count, "line" (line seg)
    CURVE_SHAPELEN => 10, #xstart, ystart, x0, y0, x1, y1, xend, yend, count, "curve" (bezier 2 points)
    CIRCLE_SHAPELEN => 5, #x, y, 5, count, "circle" (center + radius)
};
#const my %SHAPELEN =
#Readonly my %SHAPELEN =>
our %SHAPELEN =
(
    rect => RECT_SHAPELEN,
    line => LINE_SHAPELEN,
    curve => CURVE_SHAPELEN,
    circle => CIRCLE_SHAPELEN,
);

#panelization:
#This will repeat the entire body the number of times indicated along the X or Y axes (files grow accordingly).
#Display elements that overhang PCB boundary can be squashed or left as-is (typically text or other silk screen markings).
#Set "overhangs" TRUE to allow overhangs, FALSE to truncate them.
#xpad and ypad allow margins to be added around outer edge of panelized PCB.
use constant PANELIZE => {'x' => 1, 'y' => 1, 'xpad' => 0, 'ypad' => 0, 'overhangs' => TRUE}; #number of times to repeat in X and Y directions

# Set this to 1 if you need TurboCAD support.
#$turboCAD = FALSE; #is this still needed as an option?

#CIRCAD pad generation uses an appropriate aperture, then moves it (stroke) "a little" - we use this to find pads and distinguish them from PCB holes. 
use constant PAD_STROKE => 0.3; #0.0005 * 600; #units are pixels
#convert very short traces to pads or holes:
use constant TRACE_MINLEN => .001; #units are inches
#use constant ALWAYS_XY => TRUE; #FALSE; #force XY even if X or Y doesn't change; NOTE: needs to be TRUE for all pads to show in FlatCAM and ViewPlot
use constant REMOVE_POLARITY => FALSE; #TRUE; #set to remove subtractive (negative) polarity; NOTE: must be FALSE for ground planes

#PDF uses "points", each point = 1/72 inch
#combined with a PDF scale factor of .12, this gives 600 dpi resolution (1/72 * .12 = 600 dpi)
use constant INCHES_PER_POINT => 1/72; #0.0138888889; #multiply point-size by this to get inches

# The precision used when computing a bezier curve. Higher numbers are more precise but slower (and generate larger files).
#$bezierPrecision = 100;
use constant BEZIER_PRECISION => 36; #100; #use const; reduced for faster rendering (mainly used for silk screen and thermal pads)

# Ground planes and silk screen or larger copper rectangles or circles are filled line-by-line using this resolution.
use constant FILL_WIDTH => .01; #fill at most 0.01 inch at a time

# The max number of characters to read into memory
use constant MAX_BYTES => 10 * M; #bumped up to 10 MB, use const

use constant DUP_DRILL1 => TRUE; #FALSE; #kludge: ViewPlot doesn't load drill files that are too small so duplicate first tool

my $runtime = time(); #Time::HiRes::gettimeofday(); #measure my execution time

print STDERR "Loaded config settings from '${\(__FILE__)}'.\n";
1; #last value must be truthful to indicate successful load


#############################################################################################
#junk/experiment:

#use Package::Constants;
#use Exporter qw(import); #https://perldoc.perl.org/Exporter.html

#my $caller = "pdf2gerb::";

#sub cfg
#{
#    my $proto = shift;
#    my $class = ref($proto) || $proto;
#    my $settings =
#    {
#        $WANT_DEBUG => 990, #10; #level of debug wanted; higher == more, lower == less, 0 == none
#    };
#    bless($settings, $class);
#    return $settings;
#}

#use constant HELLO => "hi there2"; #"main::HELLO" => "hi there";
#use constant GOODBYE => 14; #"main::GOODBYE" => 12;

#print STDERR "read cfg file\n";

#our @EXPORT_OK = Package::Constants->list(__PACKAGE__); #https://www.perlmonks.org/?node_id=1072691; NOTE: "_OK" skips short/common names

#print STDERR scalar(@EXPORT_OK) . " consts exported:\n";
#foreach(@EXPORT_OK) { print STDERR "$_\n"; }
#my $val = main::thing("xyz");
#print STDERR "caller gave me $val\n";
#foreach my $arg (@ARGV) { print STDERR "arg $arg\n"; }

---

Download Details:

Author: swannman
Source Code: https://github.com/swannman/pdf2gerb

License: GPL-3.0 license

#perl 

Useful Swift Extension

After working with Swift for some time I found there are lot of things that aren’t there out of the box as with other languages. Following are some extensions that I think are useful for day to day working

Accessing string element by index

extension String {
    subscript(i:Int) ->Character {
        let index = self.index(self.startIndex, offsetBy: i)
        return self[index]
    }
}

#useful #development #swift #extension #swift-extensions

10 Free Online Resources To Learn Swift Language

Swift is a fast and efficient general-purpose programming language that provides real-time feedback and can be seamlessly incorporated into existing Objective-C code. This is why developers are able to write safer, more reliable code while saving time. It aims to be the best language that can be used for various purposes ranging from systems programming to mobile as well as desktop apps and scaling up to cloud services.

Below here, we list down the 10 best online resources to learn Swift language.

(The list is in no particular order)

#developers corner #free online resources to learn swift language #learn swift #learn swift free #learn swift online free #resources to learn swift #swift language #swift programming

Top Swift Development Companies | Top Swift Developers - TopDevelopers.co

A thoroughly researched list of top Swift developers with ratings & reviews to help find the best Swift development companies around the world.

#swift development service providers #best swift development companies #top swift development companies #swift development solutions #top swift developers #swift

Hire Dedicated Swift Developers

Want to create a native iOS application for your Startup?

Hire Dedicated Swift Developers for end-to-end services like development, migration, upgrade, testing, and support & maintenance. Trust HourlyDeveloper.io our Swift development team for iOS device apps that are high on performance and security.

Consult with experts:- https://bit.ly/2C5M6cz

#hire dedicated swift developers #swift developers #swift development company #swift development services #swift development #swift