acpi/acpica/uthex.c

0001 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
0002 /******************************************************************************
0003  *
0004  * Module Name: uthex -- Hex/ASCII support functions
0005  *
0006  * Copyright (C) 2000 - 2022, Intel Corp.
0007  *
0008  *****************************************************************************/
0009
0010 #include <acpi/acpi.h>
0011 #include "accommon.h"
0012
0013 #define _COMPONENT          ACPI_COMPILER
0014 ACPI_MODULE_NAME("uthex")
0015
0016 /* Hex to ASCII conversion table */
0017 static const char acpi_gbl_hex_to_ascii[] = {
0018     '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
0019         'E', 'F'
0020 };
0021
0022 /*******************************************************************************
0023  *
0024  * FUNCTION:    acpi_ut_hex_to_ascii_char
0025  *
0026  * PARAMETERS:  integer             - Contains the hex digit
0027  *              position            - bit position of the digit within the
0028  *                                    integer (multiple of 4)
0029  *
0030  * RETURN:      The converted Ascii character
0031  *
0032  * DESCRIPTION: Convert a hex digit to an Ascii character
0033  *
0034  ******************************************************************************/
0035
0036 char acpi_ut_hex_to_ascii_char(u64 integer, u32 position)
0037 {
0038     u64 index;
0039
0040     acpi_ut_short_shift_right(integer, position, &index);
0041     return (acpi_gbl_hex_to_ascii[index & 0xF]);
0042 }
0043
0044 /*******************************************************************************
0045  *
0046  * FUNCTION:    acpi_ut_ascii_to_hex_byte
0047  *
0048  * PARAMETERS:  two_ascii_chars             - Pointer to two ASCII characters
0049  *              return_byte                 - Where converted byte is returned
0050  *
0051  * RETURN:      Status and converted hex byte
0052  *
0053  * DESCRIPTION: Perform ascii-to-hex translation, exactly two ASCII characters
0054  *              to a single converted byte value.
0055  *
0056  ******************************************************************************/
0057
0058 acpi_status acpi_ut_ascii_to_hex_byte(char *two_ascii_chars, u8 *return_byte)
0059 {
0060
0061     /* Both ASCII characters must be valid hex digits */
0062
0063     if (!isxdigit((int)two_ascii_chars[0]) ||
0064         !isxdigit((int)two_ascii_chars[1])) {
0065         return (AE_BAD_HEX_CONSTANT);
0066     }
0067
0068     *return_byte =
0069         acpi_ut_ascii_char_to_hex(two_ascii_chars[1]) |
0070         (acpi_ut_ascii_char_to_hex(two_ascii_chars[0]) << 4);
0071
0072     return (AE_OK);
0073 }
0074
0075 /*******************************************************************************
0076  *
0077  * FUNCTION:    acpi_ut_ascii_char_to_hex
0078  *
0079  * PARAMETERS:  hex_char                - Hex character in Ascii. Must be:
0080  *                                        0-9 or A-F or a-f
0081  *
0082  * RETURN:      The binary value of the ascii/hex character
0083  *
0084  * DESCRIPTION: Perform ascii-to-hex translation
0085  *
0086  ******************************************************************************/
0087
0088 u8 acpi_ut_ascii_char_to_hex(int hex_char)
0089 {
0090
0091     /* Values 0-9 */
0092
0093     if (hex_char <= '9') {
0094         return ((u8)(hex_char - '0'));
0095     }
0096
0097     /* Upper case A-F */
0098
0099     if (hex_char <= 'F') {
0100         return ((u8)(hex_char - 0x37));
0101     }
0102
0103     /* Lower case a-f */
0104
0105     return ((u8)(hex_char - 0x57));
0106 }