I have a long array. How to write this array to a binary file?
Problem is that if I convert it into byte array some values are changed.
The array is like:
long array = new long[160000];
Give some code snippet.
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3 Answers
The BinaryFormatter will be the easiest.
Also valuetypes (I assume this is what you mean by long), serializes very efficiently.
Comments
var array = new[] { 1L, 2L, 3L };
using (var stream = new FileStream("test.bin", FileMode.Create, FileAccess.Write, FileShare.None))
using (var writer = new BinaryWriter(stream))
{
foreach (long item in array)
{
writer.Write(item);
}
}
1 Comment
Darin Dimitrov
@leppie, I agree with you. I've performed some measurements and using
BinaryFormatter as you suggested performs better.How are the values changed? And an array of long can be copied into an array of byte very quickly, no need for serialization.
static void Main(string[] args) {
System.Random random = new Random();
long[] arrayOriginal = new long[160000];
long[] arrayRead = null;
for (int i =0 ; i < arrayOriginal.Length; i++) {
arrayOriginal[i] = random.Next(int.MaxValue) * random.Next(int.MaxValue);
}
byte[] bytesOriginal = new byte[arrayOriginal.Length * sizeof(long)];
System.Buffer.BlockCopy(arrayOriginal, 0, bytesOriginal, 0, bytesOriginal.Length);
using (System.IO.MemoryStream stream = new System.IO.MemoryStream()) {
// write
stream.Write(bytesOriginal, 0, bytesOriginal.Length);
// reset
stream.Flush();
stream.Position = 0;
int expectedLength = 0;
checked {
expectedLength = (int)stream.Length;
}
// read
byte[] bytesRead = new byte[expectedLength];
if (expectedLength == stream.Read(bytesRead, 0, expectedLength)) {
arrayRead = new long[expectedLength / sizeof(long)];
Buffer.BlockCopy(bytesRead, 0, arrayRead, 0, expectedLength);
}
else {
// exception
}
// check
for (int i = 0; i < arrayOriginal.Length; i++) {
if (arrayOriginal[i] != arrayRead[i]) {
throw new System.Exception();
}
}
}
System.Console.WriteLine("Done");
System.Console.ReadKey();
}
