Danielle Danielle - 2 months ago 20
C# Question

How to detect if a byte is a line break when reading from a CSV file byte by byte - C#

I need to read from a CSV file byte by byte (Note: I don't want to read line by line).
How can I detect if the byte that was read is a line break ?
How to know that end of line was reached ?

int count = 0;
byte[] buffer = new byte[MAX_BUFFER];

using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
{
// Read bytes form file until the next line break -or- eof
// so we don't break a csv row in the middle

// What should be instead of the 'xxx' ?

while (((readByte = fs.ReadByte()) != 'xxx') && (readByte != -1))
{
buffer[count] = Convert.ToByte(readByte);
count++;
}
}

Answer

New line character has decimal value 10 or hex value 0xA. In order to check new line character compare the result against 0xA

int count = 0;
byte[] buffer = new byte[MAX_BUFFER];

using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
{              
    // Read bytes form file until the next line break -or- eof 
    // so we don't break a csv row in the middle

    // What should be instead of the 'xxx' ?

    while (((readByte = fs.ReadByte()) != 0xA) && (readByte != -1))
    {
        buffer[count] = Convert.ToByte(readByte);
        count++;
    }
} 

When readByte is equal to 10 or 0xA in hex, the condition will be false. Have a look at the ASCII Table for more information.

UPDATE

You might also want to define a constant like const int NEW_LINE = 0xA and use that instead of just 0xA in the while statement. This is just to help you figure out later when that 0xA actually means.