LXR linux/drivers/acpi/acpica/uthex.c

   1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2/******************************************************************************
   3 *
   4 * Module Name: uthex -- Hex/ASCII support functions
   5 *
   6 * Copyright (C) 2000 - 2018, Intel Corp.
   7 *
   8 *****************************************************************************/
   9
  10#include <acpi/acpi.h>
  11#include "accommon.h"
  12
  13#define _COMPONENT          ACPI_COMPILER
  14ACPI_MODULE_NAME("uthex")
  15
  16/* Hex to ASCII conversion table */
  17static const char acpi_gbl_hex_to_ascii[] = {
  18        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
  19            'E', 'F'
  20};
  21
  22/*******************************************************************************
  23 *
  24 * FUNCTION:    acpi_ut_hex_to_ascii_char
  25 *
  26 * PARAMETERS:  integer             - Contains the hex digit
  27 *              position            - bit position of the digit within the
  28 *                                    integer (multiple of 4)
  29 *
  30 * RETURN:      The converted Ascii character
  31 *
  32 * DESCRIPTION: Convert a hex digit to an Ascii character
  33 *
  34 ******************************************************************************/
  35
  36char acpi_ut_hex_to_ascii_char(u64 integer, u32 position)
  37{
  38        u64 index;
  39
  40        acpi_ut_short_shift_right(integer, position, &index);
  41        return (acpi_gbl_hex_to_ascii[index & 0xF]);
  42}
  43
  44/*******************************************************************************
  45 *
  46 * FUNCTION:    acpi_ut_ascii_to_hex_byte
  47 *
  48 * PARAMETERS:  two_ascii_chars             - Pointer to two ASCII characters
  49 *              return_byte                 - Where converted byte is returned
  50 *
  51 * RETURN:      Status and converted hex byte
  52 *
  53 * DESCRIPTION: Perform ascii-to-hex translation, exactly two ASCII characters
  54 *              to a single converted byte value.
  55 *
  56 ******************************************************************************/
  57
  58acpi_status acpi_ut_ascii_to_hex_byte(char *two_ascii_chars, u8 *return_byte)
  59{
  60
  61        /* Both ASCII characters must be valid hex digits */
  62
  63        if (!isxdigit((int)two_ascii_chars[0]) ||
  64            !isxdigit((int)two_ascii_chars[1])) {
  65                return (AE_BAD_HEX_CONSTANT);
  66        }
  67
  68        *return_byte =
  69            acpi_ut_ascii_char_to_hex(two_ascii_chars[1]) |
  70            (acpi_ut_ascii_char_to_hex(two_ascii_chars[0]) << 4);
  71
  72        return (AE_OK);
  73}
  74
  75/*******************************************************************************
  76 *
  77 * FUNCTION:    acpi_ut_ascii_char_to_hex
  78 *
  79 * PARAMETERS:  hex_char                - Hex character in Ascii. Must be:
  80 *                                        0-9 or A-F or a-f
  81 *
  82 * RETURN:      The binary value of the ascii/hex character
  83 *
  84 * DESCRIPTION: Perform ascii-to-hex translation
  85 *
  86 ******************************************************************************/
  87
  88u8 acpi_ut_ascii_char_to_hex(int hex_char)
  89{
  90
  91        /* Values 0-9 */
  92
  93        if (hex_char <= '9') {
  94                return ((u8)(hex_char - '0'));
  95        }
  96
  97        /* Upper case A-F */
  98
  99        if (hex_char <= 'F') {
 100                return ((u8)(hex_char - 0x37));
 101        }
 102
 103        /* Lower case a-f */
 104
 105        return ((u8)(hex_char - 0x57));
 106}
 107