/*
   * lib/hexdump.c
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation. See README and COPYING for
   * more details.
   */
  
  #include <linux/types.h>
  #include <linux/ctype.h>
  #include <linux/kernel.h>
  #include <linux/module.h>

  const char hex_asc[] = "0123456789abcdef";
  EXPORT_SYMBOL(hex_asc);

  /**
   * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
   * @buf: data blob to dump
   * @len: number of bytes in the @buf

   * @rowsize: number of bytes to print per line; must be 16 or 32
   * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)

   * @linebuf: where to put the converted data
   * @linebuflen: total size of @linebuf, including space for terminating NUL

   * @ascii: include ASCII after the hex output

   *
   * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,

   * 16 or 32 bytes of input data converted to hex + ASCII output.

   *
   * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
   * to a hex + ASCII dump at the supplied memory location.
   * The converted output is always NUL-terminated.
   *
   * E.g.:

   *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
   *			linebuf, sizeof(linebuf), 1);

   *
   * example output buffer:

   * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO

   */

  void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
  			int groupsize, char *linebuf, size_t linebuflen,
  			bool ascii)

  {
  	const u8 *ptr = buf;
  	u8 ch;
  	int j, lx = 0;

  	int ascii_column;

  	if (rowsize != 16 && rowsize != 32)
  		rowsize = 16;
  
  	if (!len)
  		goto nil;
  	if (len > rowsize)		/* limit to one line at a time */
  		len = rowsize;
  	if ((len % groupsize) != 0)	/* no mixed size output */
  		groupsize = 1;
  
  	switch (groupsize) {
  	case 8: {
  		const u64 *ptr8 = buf;
  		int ngroups = len / groupsize;
  
  		for (j = 0; j < ngroups; j++)
  			lx += scnprintf(linebuf + lx, linebuflen - lx,
  				"%16.16llx ", (unsigned long long)*(ptr8 + j));
  		ascii_column = 17 * ngroups + 2;
  		break;
  	}
  
  	case 4: {
  		const u32 *ptr4 = buf;
  		int ngroups = len / groupsize;
  
  		for (j = 0; j < ngroups; j++)
  			lx += scnprintf(linebuf + lx, linebuflen - lx,
  				"%8.8x ", *(ptr4 + j));
  		ascii_column = 9 * ngroups + 2;
  		break;
  	}
  
  	case 2: {
  		const u16 *ptr2 = buf;
  		int ngroups = len / groupsize;
  
  		for (j = 0; j < ngroups; j++)
  			lx += scnprintf(linebuf + lx, linebuflen - lx,
  				"%4.4x ", *(ptr2 + j));
  		ascii_column = 5 * ngroups + 2;
  		break;
  	}
  
  	default:
  		for (j = 0; (j < rowsize) && (j < len) && (lx + 4) < linebuflen;
  		     j++) {
  			ch = ptr[j];

  			linebuf[lx++] = hex_asc_hi(ch);
  			linebuf[lx++] = hex_asc_lo(ch);

  			linebuf[lx++] = ' ';

  		}
  		ascii_column = 3 * rowsize + 2;
  		break;

  	}

  	if (!ascii)
  		goto nil;
  
  	while (lx < (linebuflen - 1) && lx < (ascii_column - 1))

  		linebuf[lx++] = ' ';

  	for (j = 0; (j < rowsize) && (j < len) && (lx + 2) < linebuflen; j++)

  		linebuf[lx++] = (isascii(ptr[j]) && isprint(ptr[j])) ? ptr[j]
  				: '.';

  nil:

  	linebuf[lx++] = '\0';
  }
  EXPORT_SYMBOL(hex_dump_to_buffer);
  
  /**
   * print_hex_dump - print a text hex dump to syslog for a binary blob of data
   * @level: kernel log level (e.g. KERN_DEBUG)

   * @prefix_str: string to prefix each line with;
   *  caller supplies trailing spaces for alignment if desired

   * @prefix_type: controls whether prefix of an offset, address, or none
   *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)

   * @rowsize: number of bytes to print per line; must be 16 or 32
   * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)

   * @buf: data blob to dump
   * @len: number of bytes in the @buf

   * @ascii: include ASCII after the hex output

   *
   * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
   * to the kernel log at the specified kernel log level, with an optional
   * leading prefix.
   *

   * print_hex_dump() works on one "line" of output at a time, i.e.,
   * 16 or 32 bytes of input data converted to hex + ASCII output.
   * print_hex_dump() iterates over the entire input @buf, breaking it into
   * "line size" chunks to format and print.
   *

   * E.g.:

   *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
   *		16, 1, frame->data, frame->len, 1);

   *

   * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
   * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
   * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
   * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.

   */

  void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
  			int rowsize, int groupsize,

  			const void *buf, size_t len, bool ascii)

  {

  	const u8 *ptr = buf;

  	int i, linelen, remaining = len;

  	unsigned char linebuf[200];

  	if (rowsize != 16 && rowsize != 32)
  		rowsize = 16;
  
  	for (i = 0; i < len; i += rowsize) {
  		linelen = min(remaining, rowsize);
  		remaining -= rowsize;
  		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
  				linebuf, sizeof(linebuf), ascii);

  
  		switch (prefix_type) {
  		case DUMP_PREFIX_ADDRESS:

  			printk("%s%s%*p: %s
  ", level, prefix_str,

  				(int)(2 * sizeof(void *)), ptr + i, linebuf);
  			break;
  		case DUMP_PREFIX_OFFSET:

  			printk("%s%s%.8x: %s
  ", level, prefix_str, i, linebuf);

  			break;
  		default:

  			printk("%s%s%s
  ", level, prefix_str, linebuf);

  			break;
  		}
  	}
  }
  EXPORT_SYMBOL(print_hex_dump);

  
  /**
   * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
   * @prefix_str: string to prefix each line with;
   *  caller supplies trailing spaces for alignment if desired
   * @prefix_type: controls whether prefix of an offset, address, or none
   *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
   * @buf: data blob to dump
   * @len: number of bytes in the @buf
   *
   * Calls print_hex_dump(), with log level of KERN_DEBUG,
   * rowsize of 16, groupsize of 1, and ASCII output included.
   */
  void print_hex_dump_bytes(const char *prefix_str, int prefix_type,

  			const void *buf, size_t len)

  {
  	print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
  			buf, len, 1);
  }
  EXPORT_SYMBOL(print_hex_dump_bytes);