util/nvramtool/hexdump.c

/*****************************************************************************\
 * hexdump.c
\*****************************************************************************/

#include "hexdump.h"

/* hexdump.c
 *
 * Copyright (C) 2002
 *     David S. Peterson.  All rights reserved.
 *
 * Author: David S. Peterson <dave_peterson@pobox.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions, and the entire permission notice, including
 *    the following disclaimer of warranties.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the entire permission notice,
 *    including the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 * 3. The name(s) of the author(s) may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * ALTERNATIVELY, this product may be distributed under the terms of the GNU
 * General Public License, in which case the provisions of the GPL are
 * required INSTEAD OF the above restrictions.  (This clause is necessary due
 * to a potential bad interaction between the GPL and the restrictions
 * contained in a BSD-style copyright.)
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

static void addrprint (FILE *outfile, uint64_t address, int width);
static void hexprint (FILE *outfile, unsigned char byte);
static void charprint (FILE *outfile, unsigned char byte,
                       unsigned char nonprintable,
                       is_printable_fn_t is_printable_fn);

/*--------------------------------------------------------------------------
 * hexdump
 *
 * Write a hex dump of 'mem' to 'outfile'.
 *
 * parameters:
 *     mem:             a pointer to the memory to display
 *     bytes:           the number of bytes of data to display
 *     addrprint_start: The address to associate with the first byte of
 *                      data.  For instance, a value of 0 indicates that the
 *                      first byte displayed should be labeled as byte 0.
 *     outfile:         The place where the hex dump should be written.
 *                      For instance, stdout or stderr may be passed here.
 *     format:          A structure specifying how the hex dump should be
 *                      formatted.
 *--------------------------------------------------------------------------*/
void hexdump (const void *mem, int bytes, uint64_t addrprint_start,
              FILE *outfile, const hexdump_format_t *format)
 { int bytes_left, index, i;
   const unsigned char *p;
   is_printable_fn_t is_printable_fn;

   /* Quietly return if the caller asks us to do something unreasonable. */
   if ((format->bytes_per_line <= 0) || (bytes < 0))
      return;

   is_printable_fn = format->is_printable_fn;

   if (is_printable_fn == NULL)
      is_printable_fn = default_is_printable_fn;

   p = (const unsigned char *) mem;
   index = 0;

   /* Each iteration handles one full line of output.  When loop terminates,
    * the number of remaining bytes to display (if any) will not be enough to
    * fill an entire line.
    */
   for (bytes_left = bytes;
        bytes_left >= format->bytes_per_line;
        bytes_left -= format->bytes_per_line)
    { /* print start address for current line */
      fprintf(outfile, format->indent);
      addrprint(outfile, addrprint_start + index, format->addrprint_width);
      fprintf(outfile, format->sep1);

      /* display the bytes in hex */
      for (i = 0; ; )
       { hexprint(outfile, p[index++]);

         if (++i >= format->bytes_per_line)
            break;

         fprintf(outfile, format->sep2);
       }

      index -= format->bytes_per_line;
      fprintf(outfile, format->sep3);

      /* display the bytes as characters */
      for (i = 0; i < format->bytes_per_line; i++)
         charprint(outfile, p[index++], format->nonprintable,
                   is_printable_fn);

      fprintf(outfile, "\n");
    }

   if (bytes_left == 0)
      return;

   /* print start address for last line */
   fprintf(outfile, format->indent);
   addrprint(outfile, addrprint_start + index, format->addrprint_width);
   fprintf(outfile, format->sep1);

   /* display bytes for last line in hex */
   for (i = 0; i < bytes_left; i++)
    { hexprint(outfile, p[index++]);
      fprintf(outfile, format->sep2);
    }

   index -= bytes_left;

   /* pad the rest of the hex byte area with spaces */
   for (; ; )
    { fprintf(outfile, "  ");

      if (++i >= format->bytes_per_line)
         break;

      fprintf(outfile, format->sep2);
    }

   fprintf(outfile, format->sep3);

   /* display bytes for last line as characters */
   for (i = 0; i < bytes_left; i++)
      charprint(outfile, p[index++], format->nonprintable, is_printable_fn);

   /* pad the rest of the character area with spaces */
   for (; i < format->bytes_per_line; i++)
      fprintf(outfile, " ");

   fprintf(outfile, "\n");
 }

/*--------------------------------------------------------------------------
 * default_is_printable_fn
 *
 * Determine whether the input character is printable.  The proper behavior
 * for this type of function may be system-dependent.  This function takes a
 * conservative approach.  If it is not adequate for your purposes, you can
 * write your own.
 *
 * parameters:
 *     c: the input character
 *
 * return value:
 *     Return 1 if the input character is printable.  Otherwise return 0.
 *--------------------------------------------------------------------------*/
int default_is_printable_fn (unsigned char c)
 { return (c >= 0x20) && (c <= 0x7e); }

/*--------------------------------------------------------------------------
 * addrprint
 *
 * Display an address as a hexadecimal number.
 *
 * parameters:
 *     outfile: the place where the output should be written
 *     address: the address to display
 *     width:   The number of bytes wide the address should be displayed as.
 *              Must be a value from 1 to 8.
 *--------------------------------------------------------------------------*/
static void addrprint (FILE *outfile, uint64_t address, int width)
 { char s[17];
   int i;

   /* force the user's input to be valid */
   if (width < 1)
      width = 1;
   else if (width > 8)
      width = 8;

   /* convert address to string */
   sprintf(s, "%016llx", (unsigned long long) address);

   /* write it out, with colons separating consecutive 16-bit chunks of the
    * address
    */
   for (i = 16 - (2 * width); ; )
    { fprintf(outfile, "%c", s[i]);

      if (++i >= 16)
         break;

      if ((i % 4) == 0)
         fprintf(outfile, ":");
    }
 }

/*--------------------------------------------------------------------------
 * hexprint
 *
 * Display a byte as a two digit hex value.
 *
 * parameters:
 *     outfile: the place where the output should be written
 *     byte:    the byte to display
 *--------------------------------------------------------------------------*/
static void hexprint (FILE *outfile, unsigned char byte)
 { static const char tbl[] =
    { '0', '1', '2', '3', '4', '5', '6', '7',
      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
    };

   fprintf(outfile, "%c%c", tbl[byte >> 4], tbl[byte & 0x0f]);
 }

/*--------------------------------------------------------------------------
 * charprint
 *
 * Display a byte as its character representation.
 *
 * parameters:
 *     outfile:         the place where the output should be written
 *     byte:            the byte to display
 *     nonprintable:    a substitute character to display if the byte
 *                      represents a nonprintable character
 *     is_printable_fn: a function that returns a boolean value indicating
 *                      whether a given character is printable
 *--------------------------------------------------------------------------*/
static void charprint (FILE *outfile, unsigned char byte,
                       unsigned char nonprintable,
                       is_printable_fn_t is_printable_fn)
 { fprintf(outfile, "%c", is_printable_fn(byte) ? byte : nonprintable); }