Re: String created from buffer has wrong length and strip() result is incorrect

[Lucas Burson via Digitalmars-d-learn]

On Friday, 17 October 2014 at 17:40:09 UTC, ketmar via 
Digitalmars-d-learn wrote:

i developed a habit of making such buffers one byte bigger than
necessary and just setting the last byte to 0 before 
converting. this
way it's guaranteed to be 0-terminated.

Perfect, great idea. Below is my utility method to pull strings 
out of a buffer.


/**
 * Get a string from buffer where the string spans [offset_start, 
offset_end).
 * Params:
 *    buffer = Buffer with an ASCII string to obtain.
 *    offset_start = Beginning byte offset within the buffer 
where the string starts.
 *    offset_end = Ending byte offset which is not included in 
the string.
 */
string bufferGetString(ubyte[] buffer, ulong offset_start, ulong 
offset_end)
in
{
   assert(buffer != null);
   assert(offset_start < offset_end);
   assert(offset_end <= buffer.length);
}
body
{
   ulong bufflen = offset_end - offset_start;

   // add one to the lenth for null-termination
   ubyte[] temp = new ubyte[bufflen+1];
   temp[0..bufflen] = buffer[offset_start..offset_end];
   temp[bufflen] = '\0';

   return strip(to!string(cast(const char*) temp.ptr));
}

unittest
{
   ubyte[] no_null = [' ', 'A', 'B', 'C', ' '];
   assert("ABC" == bufferGetString(no_null, 0, no_null.length));
   assert("ABC" == bufferGetString(no_null, 1, no_null.length-1));
   assert("A" == bufferGetString(no_null, 1, 2));
}