archival/libunarchive/copy_file_chunk_fd.c

   1 #include <unistd.h>
   2 #include <sys/types.h>
   3 #include "libbb.h"
   4
   5 /* Copy CHUNKSIZE bytes (or untill EOF if chunksize == -1)
   6  * from SRC_FILE to DST_FILE. */
   7 extern int copy_file_chunk_fd(int src_fd, int dst_fd, off_t chunksize)
   8 {
   9         size_t nread, size;
  10         char buffer[BUFSIZ];
  11
  12         while (chunksize != 0) {
  13                 if (chunksize > BUFSIZ) {
  14                         size = BUFSIZ;
  15                 } else {
  16                         size = chunksize;
  17                 }
  18                 nread = xread(src_fd, buffer, size);
  19                 if (nread == 0) {
  20                         return 1;
  21                 }
  22
  23                 if (write (dst_fd, buffer, nread) != nread) {
  24                         error_msg_and_die ("Short write");
  25                 }
  26
  27                 if (chunksize != -1) {
  28                         chunksize -= nread;
  29                 }
  30         }
  31
  32         return 0;
  33 }