ascii.c

linux下的轻量级的ftp服务器

/*
 * Part of Very Secure FTPd
 * Licence: GPL v2
 * Author: Chris Evans
 * ascii.c
 *
 * Routines to handle ASCII mode tranfers. Yuk.
 */

#include "ascii.h"

struct ascii_to_bin_ret
vsf_ascii_ascii_to_bin(char* p_buf, unsigned int in_len, int prev_cr)
{
  /* Task: translate all \r\n into plain \n. A plain \r not followed by \n must
   * not be removed.
   */
  struct ascii_to_bin_ret ret;
  unsigned int indexx = 0;
  unsigned int written = 0;
  char* p_out = p_buf + 1;
  ret.last_was_cr = 0;
  if (prev_cr && (!in_len || p_out[0] != '\n'))
  {
    p_buf[0] = '\r';
    ret.p_buf = p_buf;
    written++;
  }
  else
  {
    ret.p_buf = p_out;
  }
  while (indexx < in_len)
  {
    char the_char = p_buf[indexx + 1];
    if (the_char != '\r')
    {
      *p_out++ = the_char;
      written++;
    }
    else if (indexx == in_len - 1)
    {
      ret.last_was_cr = 1;
    }
    else if (p_buf[indexx + 2] != '\n')
    {
      *p_out++ = the_char;
      written++;
    }
    indexx++;
  }
  ret.stored = written;
  return ret;
}

unsigned int
vsf_ascii_bin_to_ascii(const char* p_in, char* p_out, unsigned int in_len)
{
  /* Task: translate all \n into \r\n. Note that \r\n becomes \r\r\n. That's
   * what wu-ftpd does, and it's easier :-)
   */
  unsigned int indexx = 0;
  unsigned int written = 0;
  while (indexx < in_len)
  {
    char the_char = p_in[indexx];
    if (the_char == '\n')
    {
      *p_out++ = '\r';
      written++;
    }
    *p_out++ = the_char;
    written++;
    indexx++;
  }
  return written;
}