You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: hexdump.rs
    path of file: ./repos/rustybox/util_linux
    
    the code of the file until where you have to start completion: use crate::libbb::appletlib::applet_name;
use crate::libbb::skip_whitespace::skip_whitespace;
use crate::librb::smallint;
use crate::librb::suffix_mult;
use libc;
use libc::fclose;
use libc::free;
use libc::getopt;
use libc::off_t;
use libc::putchar_unlocked;
use libc::sscanf;
use libc::strchr;
use libc::FILE;
extern "C" {

  #[no_mangle]
  static mut optarg: *mut libc::c_char;

  #[no_mangle]
  static mut optind: libc::c_int;

  #[no_mangle]
  static mut stdin: *mut FILE;

  #[no_mangle]
  static bkm_suffixes: [suffix_mult; 0];

/*
 * ascii-to-numbers implementations for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
/* Provides extern declarations of functions */
/* Unsigned long long functions always exist */

}

/* %_A */
/* rep count set, not default */
/* print offset */
/* blank pad */
/* %_c */
/* %c */
/* %[EefGf] */
/* %[di] */
/* %_p */
/* %s */
/* %_u */
/* %[ouXx] */
/* no conversions */

pub type dump_vflag_t = libc::c_uint;
// pub const WAIT: dump_vflag_t = 3;
// pub const FIRST: dump_vflag_t = 2;
// pub const DUP: dump_vflag_t = 1;
pub const ALL: dump_vflag_t = 0;

#[repr(C)]
#[derive(Copy, Clone)]
pub struct PR {
  pub nextpr: *mut PR,
  pub flags: libc::c_uint,
  pub bcnt: libc::c_int,
  pub cchar: *mut libc::c_char,
  pub fmt: *mut libc::c_char,
  pub nospace: *mut libc::c_char,
}

#[repr(C)]
#[derive(Copy, Clone)]
pub struct FU {
  pub nextfu: *mut FU,
  pub nextpr: *mut PR,
  pub flags: libc::c_uint,
  pub reps: libc::c_int,
  pub bcnt: libc::c_int,
  pub fmt: *mut libc::c_char,
}

#[repr(C)]
#[derive(Copy, Clone)]
pub struct FS {
  pub nextfs: *mut FS,
  pub nextfu: *mut FU,
  pub bcnt: libc::c_int,
}

use crate::libbb::dump::dumper_t;

#[inline(always)]
unsafe fn bb_ascii_isxdigit(mut a: libc::c_uchar) -> libc::c_int {
  let mut b: libc::c_uchar = (a as libc::c_int - '0' as i32) as libc::c_uchar;
  if b as libc::c_int <= 9i32 {
    return (b as libc::c_int <= 9i32) as libc::c_int;
  }
  b = ((a as libc::c_int | 0x20i32) - 'a' as i32) as libc::c_uchar;
  return (b as libc::c_int <= 'f' as i32 - 'a' as i32) as libc::c_int;
}

/*
 * hexdump implementation for busybox
 * Based on code from util-linux v 2.11l
 *
 * Copyright (c) 1989
 * The Regents of the University of California.  All rights reserved.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//config:config HEXDUMP
//config:	bool "hexdump (8.6 kb)"
//config:	default y
//config:	help
//config:	The hexdump utility is used to display binary data in a readable
//config:	way that is comparable to the output from most hex editors.
//config:
//config:config FEATURE_HEXDUMP_REVERSE
//config:	bool "Support -R, reverse of 'hexdump -Cv'"
//config:	default y
//config:	depends on HEXDUMP
//config:	help
//config:	The hexdump utility is used to display binary data in an ascii
//config:	readable way. This option creates binary data from an ascii input.
//config:	NB: this option is non-standard. It's unwise to use it in scripts
//config:	aimed to be portable.
//config:
//config:config HD
//config:	bool "hd (7.8 kb)"
//config:	default y
//config:	help
//config:	hd is an alias to hexdump -C.
//applet:IF_HEXDUMP(APPLET_NOEXEC(hexdump, hexdump, BB_DIR_USR_BIN, SUID_DROP, hexdump))
//applet:IF_HD(APPLET_NOEXEC(hd, hexdump, BB_DIR_USR_BIN, SUID_DROP, hd))
//kbuild:lib-$(CONFIG_HEXDUMP) += hexdump.o
//kbuild:lib-$(CONFIG_HD) += hexdump.o
//usage:#define hexdump_trivial_usage
//usage:       "[-bcCdefnosvx" IF_FEATURE_HEXDUMP_REVERSE("R") "] [FILE]..."
//usage:#define hexdump_full_usage "\n\n"
//usage:       "Display FILEs (or stdin) in a user specified format\n"
//usage:     "\n	-b		1-byte octal display"
//usage:     "\n	-c		1-byte character display"
//usage:     "\n	-d		2-byte decimal display"
//usage:     "\n	-o		2-byte octal display"
//usage:     "\n	-x		2-byte hex display"
//usage:     "\n	
    
pub unsafe fn hexdump_main(mut argc: libc::c_int, mut argv: *mut *mut libc::c_char) -> libc::c_int {
  let mut buf: *mut libc::c_char = std::ptr::null_mut::<libc::c_char>();
  let mut current_block: u64;
  let mut dumper: *mut dumper_t = crate::libbb::dump::alloc_dumper();
  let mut p: *const libc::c_char = std::ptr::null();
  let mut ch: libc::c_int = 0;
  let mut fp: *mut FILE = std::ptr::null_mut();
  let mut rdump: smallint = 0 as smallint;
  if 1i32 != 0 && (1i32 == 0 || *applet_name.offset(2) == 0) {
    /* we are "hd" */
    ch = 'C' as i32;
    current_block = 9286514861260803080;
  } else {
    current_block = 6873731126896040597;
  }
  loop {
    match current_block {
      6873731126896040597 =>
      /* We cannot use getopt32: in hexdump options are cumulative.
       * E.g. "hexdump -C -C file" should dump each line twice */
      {
        ch = getopt(argc, argv, hexdump_opts.as_ptr());
        if !(ch > 0) {
          break;
        }
        p = strchr(hexdump_opts.as_ptr(), ch);
        if p.is_null() {
          crate::libbb::appletlib::bb_show_usage();
        }
        if (p.wrapping_offset_from(hexdump_opts.as_ptr()) as libc::c_long) < 5i32 as libc::c_long {
          crate::libbb::dump::bb_dump_add(dumper, add_first.as_ptr());
          crate::libbb::dump::bb_dump_add(
            dumper,
            add_strings[p.wrapping_offset_from(hexdump_opts.as_ptr()) as libc::c_long as libc::c_int
              as usize],
          );
        }
        /* Save a little bit of space below by omitting the 'else's. */
        if ch == 'C' as i32 {
          current_block = 9286514861260803080; // final address line after dump
          continue;
        }
      }
      _ => {
        crate::libbb::dump::bb_dump_add(
          dumper,
          b"\"%08.8_Ax\n\"\x00" as *const u8 as *const libc::c_char,
        );
        //------------------- "address  "   8 * "xx "    "  "  8 * "xx "
        crate::libbb::dump::bb_dump_add(
          dumper,
          b"\"%08.8_ax  \"8/1 \"%02x \"\"  \"8/1 \"%02x \"\x00" as *const u8 as *const libc::c_char,
        );
        //------------------- "  |ASCII...........|\n"
        crate::libbb::dump::bb_dump_add(
          dumper,
          b"\"  |\"16/1 \"%_p\"\"|\n\"\x00" as *const u8 as *const libc::c_char,
        ); /* else */
      }
    } /* else */
    if ch == 'e' as i32 {
      crate::libbb::dump::bb_dump_add(dumper, optarg); /* else */
    } /* else */
    if ch == 'f' as i32 {
      bb_dump_addfile(dumper, optarg);
    }
    if ch == 'n' as i32 {
      (*dumper).dump_length = crate::libbb::xatonum::xatoi_positive(optarg)
    }
    if ch == 's' as i32 {
      /* compat: -s accepts hex numbers too */
      (*dumper).dump_skip = crate::libbb::xatonum::xstrtoull_range_sfx(
        optarg,
        0,
        0 as libc::c_ulonglong,
        !((1i32 as off_t)
          << (::std::mem::size_of::<off_t>() as libc::c_ulong)
            .wrapping_mul(8i32 as libc::c_ulong)
            .wrapping_sub(1i32 as libc::c_ulong)) as libc::c_ulonglong,
        bkm_suffixes.as_ptr(),
      ) as off_t
    }
    if ch == 'v' as i32 {
      (*dumper).dump_vflag = ALL as libc::c_int as smallint
    }
    if ch == 'R' as i32 {
      rdump = 1i32 as smallint
    }
    current_block = 6873731126896040597;
  }
  if (*dumper).fshead.is_null() {
    crate::libbb::dump::bb_dump_add(dumper, add_first.as_ptr());
    crate::libbb::dump::bb_dump_add(
      dumper,
      b"\"%07.7_ax \"8/2 \"%04x \"\"\n\"\x00" as *const u8 as *const libc::c_char,
    );
  }
  argv = argv.offset(optind as isize);
  if rdump == 0 {
    return crate::libbb::dump::bb_dump_dump(dumper, argv);
  }
  /* -R: reverse of 'hexdump -Cv' */
  fp = stdin;
  if (*argv).is_null() {
    argv = argv.offset(-1);
    current_block = 6590038594373520143;
  } else {
    current_block = 6717214610478484138;
  }
  loop {
    match current_block {
      6590038594373520143 => {
        loop {
          buf = crate::libbb::get_line_from_file::xmalloc_fgetline(fp);
          if buf.is_null() {
            break;
          }
          p = buf;
          loop {
            /* skip address or previous byte */
            while bb_ascii_isxdigit(*p as libc::c_uchar) != 0 {
              p = p.offset(1)
            }
            while *p as libc::c_int == ' ' as i32 {
              p = p.offset(1)
            }
            /* '|' char will break the line */
            if bb_ascii_isxdigit(*p as libc::c_uchar) == 0
              || sscanf(
                p,
                b"%x \x00" as *const u8 as *const libc::c_char,
                &mut ch as *mut libc::c_int,
              ) != 1i32
            {
              break;
            }
            putchar_unlocked(ch);
          }
          free(buf as *mut libc::c_void);
        }
        fclose(fp);
        argv = argv.offset(1);
        if !(*argv).is_null() {
          current_block = 6717214610478484138;
        } else {
          break;
        }
      }
      _ => {
        buf = std::ptr::null_mut::<libc::c_char>();
        fp = crate::libbb::wfopen::xfopen_for_read(*argv);
        current_block = 6590038594373520143;
      }
    }
  }
  crate::libbb::fflush_stdout_and_exit::fflush_stdout_and_exit(0i32);
}