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linux/drivers/acpi/acpica/utstrsuppt.c

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/*******************************************************************************
*
* Module Name: utstrsuppt - Support functions for string-to-integer conversion
*
******************************************************************************/
/*
* Copyright (C) 2000 - 2018, Intel Corp.
* All rights reserved.
*
* 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 following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
*/
#include <acpi/acpi.h>
#include "accommon.h"
#define _COMPONENT ACPI_UTILITIES
ACPI_MODULE_NAME("utstrsuppt")
/* Local prototypes */
static acpi_status
acpi_ut_insert_digit(u64 *accumulated_value, u32 base, int ascii_digit);
static acpi_status
acpi_ut_strtoul_multiply64(u64 multiplicand, u32 base, u64 *out_product);
static acpi_status acpi_ut_strtoul_add64(u64 addend1, u32 digit, u64 *out_sum);
/*******************************************************************************
*
* FUNCTION: acpi_ut_convert_octal_string
*
* PARAMETERS: string - Null terminated input string
* return_value_ptr - Where the converted value is returned
*
* RETURN: Status and 64-bit converted integer
*
* DESCRIPTION: Performs a base 8 conversion of the input string to an
* integer value, either 32 or 64 bits.
*
* NOTE: Maximum 64-bit unsigned octal value is 01777777777777777777777
* Maximum 32-bit unsigned octal value is 037777777777
*
******************************************************************************/
acpi_status acpi_ut_convert_octal_string(char *string, u64 *return_value_ptr)
{
u64 accumulated_value = 0;
acpi_status status = AE_OK;
/* Convert each ASCII byte in the input string */
while (*string) {
/* Character must be ASCII 0-7, otherwise terminate with no error */
if (!(ACPI_IS_OCTAL_DIGIT(*string))) {
break;
}
/* Convert and insert this octal digit into the accumulator */
status = acpi_ut_insert_digit(&accumulated_value, 8, *string);
if (ACPI_FAILURE(status)) {
status = AE_OCTAL_OVERFLOW;
break;
}
string++;
}
/* Always return the value that has been accumulated */
*return_value_ptr = accumulated_value;
return (status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_convert_decimal_string
*
* PARAMETERS: string - Null terminated input string
* return_value_ptr - Where the converted value is returned
*
* RETURN: Status and 64-bit converted integer
*
* DESCRIPTION: Performs a base 10 conversion of the input string to an
* integer value, either 32 or 64 bits.
*
* NOTE: Maximum 64-bit unsigned decimal value is 18446744073709551615
* Maximum 32-bit unsigned decimal value is 4294967295
*
******************************************************************************/
acpi_status acpi_ut_convert_decimal_string(char *string, u64 *return_value_ptr)
{
u64 accumulated_value = 0;
acpi_status status = AE_OK;
/* Convert each ASCII byte in the input string */
while (*string) {
/* Character must be ASCII 0-9, otherwise terminate with no error */
if (!isdigit(*string)) {
break;
}
/* Convert and insert this decimal digit into the accumulator */
status = acpi_ut_insert_digit(&accumulated_value, 10, *string);
if (ACPI_FAILURE(status)) {
status = AE_DECIMAL_OVERFLOW;
break;
}
string++;
}
/* Always return the value that has been accumulated */
*return_value_ptr = accumulated_value;
return (status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_convert_hex_string
*
* PARAMETERS: string - Null terminated input string
* return_value_ptr - Where the converted value is returned
*
* RETURN: Status and 64-bit converted integer
*
* DESCRIPTION: Performs a base 16 conversion of the input string to an
* integer value, either 32 or 64 bits.
*
* NOTE: Maximum 64-bit unsigned hex value is 0xFFFFFFFFFFFFFFFF
* Maximum 32-bit unsigned hex value is 0xFFFFFFFF
*
******************************************************************************/
acpi_status acpi_ut_convert_hex_string(char *string, u64 *return_value_ptr)
{
u64 accumulated_value = 0;
acpi_status status = AE_OK;
/* Convert each ASCII byte in the input string */
while (*string) {
/* Must be ASCII A-F, a-f, or 0-9, otherwise terminate with no error */
if (!isxdigit(*string)) {
break;
}
/* Convert and insert this hex digit into the accumulator */
status = acpi_ut_insert_digit(&accumulated_value, 16, *string);
if (ACPI_FAILURE(status)) {
status = AE_HEX_OVERFLOW;
break;
}
string++;
}
/* Always return the value that has been accumulated */
*return_value_ptr = accumulated_value;
return (status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_remove_leading_zeros
*
* PARAMETERS: string - Pointer to input ASCII string
*
* RETURN: Next character after any leading zeros. This character may be
* used by the caller to detect end-of-string.
*
* DESCRIPTION: Remove any leading zeros in the input string. Return the
* next character after the final ASCII zero to enable the caller
* to check for the end of the string (NULL terminator).
*
******************************************************************************/
char acpi_ut_remove_leading_zeros(char **string)
{
while (**string == ACPI_ASCII_ZERO) {
*string += 1;
}
return (**string);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_remove_whitespace
*
* PARAMETERS: string - Pointer to input ASCII string
*
* RETURN: Next character after any whitespace. This character may be
* used by the caller to detect end-of-string.
*
* DESCRIPTION: Remove any leading whitespace in the input string. Return the
* next character after the final ASCII zero to enable the caller
* to check for the end of the string (NULL terminator).
*
******************************************************************************/
char acpi_ut_remove_whitespace(char **string)
{
while (isspace((u8)**string)) {
*string += 1;
}
return (**string);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_detect_hex_prefix
*
* PARAMETERS: string - Pointer to input ASCII string
*
* RETURN: TRUE if a "0x" prefix was found at the start of the string
*
* DESCRIPTION: Detect and remove a hex "0x" prefix
*
******************************************************************************/
u8 acpi_ut_detect_hex_prefix(char **string)
{
if ((**string == ACPI_ASCII_ZERO) &&
(tolower((int)*(*string + 1)) == 'x')) {
*string += 2; /* Go past the leading 0x */
return (TRUE);
}
return (FALSE); /* Not a hex string */
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_detect_octal_prefix
*
* PARAMETERS: string - Pointer to input ASCII string
*
* RETURN: True if an octal "0" prefix was found at the start of the
* string
*
* DESCRIPTION: Detect and remove an octal prefix (zero)
*
******************************************************************************/
u8 acpi_ut_detect_octal_prefix(char **string)
{
if (**string == ACPI_ASCII_ZERO) {
*string += 1; /* Go past the leading 0 */
return (TRUE);
}
return (FALSE); /* Not an octal string */
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_insert_digit
*
* PARAMETERS: accumulated_value - Current value of the integer value
* accumulator. The new value is
* returned here.
* base - Radix, either 8/10/16
* ascii_digit - ASCII single digit to be inserted
*
* RETURN: Status and result of the convert/insert operation. The only
* possible returned exception code is numeric overflow of
* either the multiply or add conversion operations.
*
* DESCRIPTION: Generic conversion and insertion function for all bases:
*
* 1) Multiply the current accumulated/converted value by the
* base in order to make room for the new character.
*
* 2) Convert the new character to binary and add it to the
* current accumulated value.
*
* Note: The only possible exception indicates an integer
* overflow (AE_NUMERIC_OVERFLOW)
*
******************************************************************************/
static acpi_status
acpi_ut_insert_digit(u64 *accumulated_value, u32 base, int ascii_digit)
{
acpi_status status;
u64 product;
/* Make room in the accumulated value for the incoming digit */
status = acpi_ut_strtoul_multiply64(*accumulated_value, base, &product);
if (ACPI_FAILURE(status)) {
return (status);
}
/* Add in the new digit, and store the sum to the accumulated value */
status =
acpi_ut_strtoul_add64(product,
acpi_ut_ascii_char_to_hex(ascii_digit),
accumulated_value);
return (status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_strtoul_multiply64
*
* PARAMETERS: multiplicand - Current accumulated converted integer
* base - Base/Radix
* out_product - Where the product is returned
*
* RETURN: Status and 64-bit product
*
* DESCRIPTION: Multiply two 64-bit values, with checking for 64-bit overflow as
* well as 32-bit overflow if necessary (if the current global
* integer width is 32).
*
******************************************************************************/
static acpi_status
acpi_ut_strtoul_multiply64(u64 multiplicand, u32 base, u64 *out_product)
{
u64 product;
u64 quotient;
/* Exit if either operand is zero */
*out_product = 0;
if (!multiplicand || !base) {
return (AE_OK);
}
/*
* Check for 64-bit overflow before the actual multiplication.
*
* Notes: 64-bit division is often not supported on 32-bit platforms
* (it requires a library function), Therefore ACPICA has a local
* 64-bit divide function. Also, Multiplier is currently only used
* as the radix (8/10/16), to the 64/32 divide will always work.
*/
acpi_ut_short_divide(ACPI_UINT64_MAX, base, &quotient, NULL);
if (multiplicand > quotient) {
return (AE_NUMERIC_OVERFLOW);
}
product = multiplicand * base;
/* Check for 32-bit overflow if necessary */
if ((acpi_gbl_integer_bit_width == 32) && (product > ACPI_UINT32_MAX)) {
return (AE_NUMERIC_OVERFLOW);
}
*out_product = product;
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_strtoul_add64
*
* PARAMETERS: addend1 - Current accumulated converted integer
* digit - New hex value/char
* out_sum - Where sum is returned (Accumulator)
*
* RETURN: Status and 64-bit sum
*
* DESCRIPTION: Add two 64-bit values, with checking for 64-bit overflow as
* well as 32-bit overflow if necessary (if the current global
* integer width is 32).
*
******************************************************************************/
static acpi_status acpi_ut_strtoul_add64(u64 addend1, u32 digit, u64 *out_sum)
{
u64 sum;
/* Check for 64-bit overflow before the actual addition */
if ((addend1 > 0) && (digit > (ACPI_UINT64_MAX - addend1))) {
return (AE_NUMERIC_OVERFLOW);
}
sum = addend1 + digit;
/* Check for 32-bit overflow if necessary */
if ((acpi_gbl_integer_bit_width == 32) && (sum > ACPI_UINT32_MAX)) {
return (AE_NUMERIC_OVERFLOW);
}
*out_sum = sum;
return (AE_OK);
}
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