Displaying 1 result from an estimated 1 matches for "readfixedstring".
2011 Aug 04
1
slightly speeding up readChar()
...simple changes that will make readChar slightly faster.
I followed readChar(useBytes=T), and tried to identify all O(N) operations, where N is the size of the file. The assumption is that for LARGE files we want to avoid any O(N) operations, and any O(N) memory allocations.
Here they are:
1. In readFixedString in envir.c, an N sized vector is
allocated, and memset to 0. O(N)
2. The file is read into the buffer with con->read O(N) (but this probably can't be dropped)
3. mkChar is called, which calls mkCharLenCE(name, strlen(name), CE_NATIVE);
strlen is O(N)
4. In mkCharLenCE, a loop along th...