public void IsSymmetric()
{
var stream = new MemoryStream();
var writer = new ReceiptWriter(stream);
#region var receipts = new Receipt[3]
var receipts = new Receipt[]
{
new Receipt
{
Date = new DateTime(2012, 5, 30),
LoyaltyCard = 1013,
Store = 555,
Items = new Item[]
{
new Item
{
GTIN = "1234567890123",
UnitPrice = 150,
Discount = 0,
Quantity = 1,
VatRate = 196
},
new Item
{
GTIN = "1234567890123",
UnitPrice = 150,
Discount = 0,
Quantity = 1,
VatRate = 196
},
new Item
{
GTIN = "1234567890124",
UnitPrice = 50,
Discount = 10,
Quantity = 5,
VatRate = 196
},
}
},
new Receipt
{
Date = new DateTime(2012, 5, 31),
LoyaltyCard = 1014,
Store = 555,
Items = new Item[]
{
new Item
{
GTIN = "1234567890124",
UnitPrice = 150,
Discount = 0,
Quantity = 1,
VatRate = 196
},
new Item
{
GTIN = "1234567890125",
UnitPrice = 250,
Discount = 0,
Quantity = 2,
VatRate = 196
},
new Item
{
GTIN = "1234567890126",
UnitPrice = 250,
Discount = 25,
Quantity = 1,
VatRate = 55
},
}
},
new Receipt
{
Date = new DateTime(2012, 5, 31),
LoyaltyCard = 1015,
Store = 555,
Items = new Item[]
{
new Item
{
GTIN = "1234567890126",
UnitPrice = 50,
Discount = 0,
Quantity = 1,
VatRate = 196
},
new Item
{
GTIN = "1234567890125",
UnitPrice = 50,
Discount = 0,
Quantity = 1,
VatRate = 196
}
}
},
};
#endregion
writer.Write(receipts[0]);
writer.Write(receipts[1]);
writer.Write(receipts[2]);
stream.Position = 0;
var reader = new ReceiptReader(stream);
var r0 = reader.Read();
var r1 = reader.Read();
var r2 = reader.Read();
// Receipt top-level info
Assert.AreEqual(receipts[0].Date, r0.Date);
Assert.AreEqual(receipts[0].LoyaltyCard, r0.LoyaltyCard);
Assert.AreEqual(receipts[0].Store, r0.Store);
Assert.AreEqual(receipts[1].Date, r1.Date);
Assert.AreEqual(receipts[1].LoyaltyCard, r1.LoyaltyCard);
Assert.AreEqual(receipts[1].Store, r1.Store);
Assert.AreEqual(receipts[2].Date, r2.Date);
Assert.AreEqual(receipts[2].LoyaltyCard, r2.LoyaltyCard);
Assert.AreEqual(receipts[2].Store, r2.Store);
// Number of items
Assert.AreEqual(receipts[0].Items.Length, r0.Items.Length);
Assert.AreEqual(receipts[1].Items.Length, r1.Items.Length);
Assert.AreEqual(receipts[2].Items.Length, r2.Items.Length);
// First receipt
Assert.AreEqual(receipts[0].Items[0].GTIN, r0.Items[0].GTIN);
Assert.AreEqual(receipts[0].Items[0].UnitPrice, r0.Items[0].UnitPrice);
Assert.AreEqual(receipts[0].Items[0].Quantity, r0.Items[0].Quantity);
Assert.AreEqual(receipts[0].Items[0].Discount, r0.Items[0].Discount);
Assert.AreEqual(receipts[0].Items[0].VatRate, r0.Items[0].VatRate);
Assert.AreEqual(receipts[0].Items[1].GTIN, r0.Items[1].GTIN);
Assert.AreEqual(receipts[0].Items[1].UnitPrice, r0.Items[1].UnitPrice);
Assert.AreEqual(receipts[0].Items[1].Quantity, r0.Items[1].Quantity);
Assert.AreEqual(receipts[0].Items[1].Discount, r0.Items[1].Discount);
Assert.AreEqual(receipts[0].Items[1].VatRate, r0.Items[1].VatRate);
Assert.AreEqual(receipts[0].Items[2].GTIN, r0.Items[2].GTIN);
Assert.AreEqual(receipts[0].Items[2].UnitPrice, r0.Items[2].UnitPrice);
Assert.AreEqual(receipts[0].Items[2].Quantity, r0.Items[2].Quantity);
Assert.AreEqual(receipts[0].Items[2].Discount, r0.Items[2].Discount);
Assert.AreEqual(receipts[0].Items[2].VatRate, r0.Items[2].VatRate);
// Second receipt
Assert.AreEqual(receipts[1].Items[0].GTIN, r1.Items[0].GTIN);
Assert.AreEqual(receipts[1].Items[0].UnitPrice, r1.Items[0].UnitPrice);
Assert.AreEqual(receipts[1].Items[0].Quantity, r1.Items[0].Quantity);
Assert.AreEqual(receipts[1].Items[0].Discount, r1.Items[0].Discount);
Assert.AreEqual(receipts[1].Items[0].VatRate, r1.Items[0].VatRate);
Assert.AreEqual(receipts[1].Items[1].GTIN, r1.Items[1].GTIN);
Assert.AreEqual(receipts[1].Items[1].UnitPrice, r1.Items[1].UnitPrice);
Assert.AreEqual(receipts[1].Items[1].Quantity, r1.Items[1].Quantity);
Assert.AreEqual(receipts[1].Items[1].Discount, r1.Items[1].Discount);
Assert.AreEqual(receipts[1].Items[1].VatRate, r1.Items[1].VatRate);
Assert.AreEqual(receipts[1].Items[2].GTIN, r1.Items[2].GTIN);
Assert.AreEqual(receipts[1].Items[2].UnitPrice, r1.Items[2].UnitPrice);
Assert.AreEqual(receipts[1].Items[2].Quantity, r1.Items[2].Quantity);
Assert.AreEqual(receipts[1].Items[2].Discount, r1.Items[2].Discount);
Assert.AreEqual(receipts[1].Items[2].VatRate, r1.Items[2].VatRate);
// Third receipt
Assert.AreEqual(receipts[2].Items[0].GTIN, r2.Items[0].GTIN);
Assert.AreEqual(receipts[2].Items[0].UnitPrice, r2.Items[0].UnitPrice);
Assert.AreEqual(receipts[2].Items[0].Quantity, r2.Items[0].Quantity);
Assert.AreEqual(receipts[2].Items[0].Discount, r2.Items[0].Discount);
Assert.AreEqual(receipts[2].Items[0].VatRate, r2.Items[0].VatRate);
Assert.AreEqual(receipts[2].Items[1].GTIN, r2.Items[1].GTIN);
Assert.AreEqual(receipts[2].Items[1].UnitPrice, r2.Items[1].UnitPrice);
Assert.AreEqual(receipts[2].Items[1].Quantity, r2.Items[1].Quantity);
Assert.AreEqual(receipts[2].Items[1].Discount, r2.Items[1].Discount);
Assert.AreEqual(receipts[2].Items[1].VatRate, r2.Items[1].VatRate);
}
public Receipt Read()
{
var reader = new MyBinaryReader(_stream);
// Reading the lookup updates
int updateCount;
try
{
updateCount = reader.Read7BitEncodedInt();
}
catch(EndOfStreamException)
{
return null;
}
for(int i = 0; i < updateCount; i++)
{
var flag = reader.Read7BitEncodedInt();
var isNewValue = ((flag & 1) == 1);
var valueType = flag >> 1; // discarding 1 bit
switch (valueType)
{
case 0: // GTINS
if(isNewValue)
{
_gtins.Add(reader.ReadString());
}
else
{
var oldIndex = reader.Read7BitEncodedInt();
var newIndex = reader.Read7BitEncodedInt();
_gtins.Swap(oldIndex, newIndex);
}
break;
case 1: // Prices
if(isNewValue)
{
_prices.Add(reader.ReadInt32());
}
else
{
var oldIndex = reader.Read7BitEncodedInt();
var newIndex = reader.Read7BitEncodedInt();
_prices.Swap(oldIndex, newIndex);
}
break;
case 2: // Discounts
if (isNewValue)
{
_discounts.Add(reader.ReadInt32());
}
else
{
var oldIndex = reader.Read7BitEncodedInt();
var newIndex = reader.Read7BitEncodedInt();
_discounts.Swap(oldIndex, newIndex);
}
break;
case 3: // VAT rates
if (isNewValue)
{
_vatRates.Add(reader.ReadInt32());
}
else
{
var oldIndex = reader.Read7BitEncodedInt();
var newIndex = reader.Read7BitEncodedInt();
_vatRates.Swap(oldIndex, newIndex);
}
break;
default:
throw new NotSupportedException();
}
}
// Reading the receipt content
var date = reader.ReadInt32().FromInt32ToDateTime();
var loyaltyCard = reader.ReadInt32();
var store = reader.ReadUInt16();
var receipt = new Receipt
{
Date = date,
LoyaltyCard = loyaltyCard,
Store = store
};
var itemCount = reader.Read7BitEncodedInt();
var items = new Item[itemCount];
for (int i = 0; i < itemCount; i++)
{
var gtinIndex = reader.Read7BitEncodedInt();
var priceIndex = reader.Read7BitEncodedInt();
var flag = reader.ReadByte();
var nonOneQuantity = ((flag & 1) == 1);
var nonZeroDiscount = ((flag & 2) == 2);
var vatRateIndex = flag >> 2; // discarding two bits
// fact: quantities equals to 1 amounts for 85% of the items.
var quantity = nonOneQuantity ? reader.Read7BitEncodedInt() : 1;
var discount = nonZeroDiscount ? reader.Read7BitEncodedInt() : 0;
items[i] = new Item
{
GTIN = _gtins[gtinIndex],
UnitPrice = _prices[priceIndex],
Quantity = quantity,
Discount = discount,
VatRate = _vatRates[vatRateIndex]
};
}
receipt.Items = items;
return receipt;
}