drivers/acpi/acpica/utstrtoul64.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: utstrtoul64 - string to 64-bit integer support
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2016, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46
  47 /*******************************************************************************
  48  *
  49  * The functions in this module satisfy the need for 64-bit string-to-integer
  50  * conversions on both 32-bit and 64-bit platforms.
  51  *
  52  ******************************************************************************/
  53
  54 #define _COMPONENT          ACPI_UTILITIES
  55 ACPI_MODULE_NAME("utstrtoul64")
  56
  57 /* Local prototypes */
  58 static u64 acpi_ut_strtoul_base10(char *string, u32 flags);
  59
  60 static u64 acpi_ut_strtoul_base16(char *string, u32 flags);
  61
  62 /*******************************************************************************
  63  *
  64  * String conversion rules as written in the ACPI specification. The error
  65  * conditions and behavior are different depending on the type of conversion.
  66  *
  67  *
  68  * Implicit data type conversion: string-to-integer
  69  * --------------------------------------------------
  70  *
  71  * Base is always 16. This is the ACPI_STRTOUL_BASE16 case.
  72  *
  73  * Example:
  74  *      Add ("BA98", Arg0, Local0)
  75  *
  76  * The integer is initialized to the value zero.
  77  * The ASCII string is interpreted as a hexadecimal constant.
  78  *
  79  *  1)  A "0x" prefix is not allowed. However, ACPICA allows this for
  80  *      compatibility with previous ACPICA. (NO ERROR)
  81  *
  82  *  2)  Terminates when the size of an integer is reached (32 or 64 bits).
  83  *      (NO ERROR)
  84  *
  85  *  3)  The first non-hex character terminates the conversion without error.
  86  *      (NO ERROR)
  87  *
  88  *  4)  Conversion of a null (zero-length) string to an integer is not
  89  *      allowed. However, ACPICA allows this for compatibility with previous
  90  *      ACPICA. This conversion returns the value 0. (NO ERROR)
  91  *
  92  *
  93  * Explicit data type conversion:  to_integer() with string operand
  94  * ---------------------------------------------------------------
  95  *
  96  * Base is either 10 (default) or 16 (with 0x prefix)
  97  *
  98  * Examples:
  99  *      to_integer ("1000")
 100  *      to_integer ("0xABCD")
 101  *
 102  *  1)  Can be (must be) either a decimal or hexadecimal numeric string.
 103  *      A hex value must be prefixed by "0x" or it is interpreted as a decimal.
 104  *
 105  *  2)  The value must not exceed the maximum of an integer value. ACPI spec
 106  *      states the behavior is "unpredictable", so ACPICA matches the behavior
 107  *      of the implicit conversion case.(NO ERROR)
 108  *
 109  *  3)  Behavior on the first non-hex character is not specified by the ACPI
 110  *      spec, so ACPICA matches the behavior of the implicit conversion case
 111  *      and terminates. (NO ERROR)
 112  *
 113  *  4)  A null (zero-length) string is illegal.
 114  *      However, ACPICA allows this for compatibility with previous ACPICA.
 115  *      This conversion returns the value 0. (NO ERROR)
 116  *
 117  ******************************************************************************/
 118
 119 /*******************************************************************************
 120  *
 121  * FUNCTION:    acpi_ut_strtoul64
 122  *
 123  * PARAMETERS:  string                  - Null terminated input string
 124  *              flags                   - Conversion info, see below
 125  *              return_value            - Where the converted integer is
 126  *                                        returned
 127  *
 128  * RETURN:      Status and Converted value
 129  *
 130  * DESCRIPTION: Convert a string into an unsigned value. Performs either a
 131  *              32-bit or 64-bit conversion, depending on the input integer
 132  *              size in Flags (often the current mode of the interpreter).
 133  *
 134  * Values for Flags:
 135  *      ACPI_STRTOUL_32BIT      - Max integer value is 32 bits
 136  *      ACPI_STRTOUL_64BIT      - Max integer value is 64 bits
 137  *      ACPI_STRTOUL_BASE16     - Input string is hexadecimal. Default
 138  *                                is 10/16 based on string prefix (0x).
 139  *
 140  * NOTES:
 141  *   Negative numbers are not supported, as they are not supported by ACPI.
 142  *
 143  *   Supports only base 16 or base 10 strings/values. Does not
 144  *   support Octal strings, as these are not supported by ACPI.
 145  *
 146  * Current users of this support:
 147  *
 148  *  interpreter - Implicit and explicit conversions, GPE method names
 149  *  debugger    - Command line input string conversion
 150  *  iASL        - Main parser, conversion of constants to integers
 151  *  iASL        - Data Table Compiler parser (constant math expressions)
 152  *  iASL        - Preprocessor (constant math expressions)
 153  *  acpi_dump   - Input table addresses
 154  *  acpi_exec   - Testing of the acpi_ut_strtoul64 function
 155  *
 156  * Note concerning callers:
 157  *   acpi_gbl_integer_byte_width can be used to set the 32/64 limit. If used,
 158  *   this global should be set to the proper width. For the core ACPICA code,
 159  *   this width depends on the DSDT version. For iASL, the default byte
 160  *   width is always 8 for the parser, but error checking is performed later
 161  *   to flag cases where a 64-bit constant is defined in a 32-bit DSDT/SSDT.
 162  *
 163  ******************************************************************************/
 164
 165 acpi_status acpi_ut_strtoul64(char *string, u32 flags, u64 *return_value)
 166 {
 167         acpi_status status = AE_OK;
 168         u32 base;
 169
 170         ACPI_FUNCTION_TRACE_STR(ut_strtoul64, string);
 171
 172         /* Parameter validation */
 173
 174         if (!string || !return_value) {
 175                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 176         }
 177
 178         *return_value = 0;
 179
 180         /* Check for zero-length string, returns 0 */
 181
 182         if (*string == 0) {
 183                 return_ACPI_STATUS(AE_OK);
 184         }
 185
 186         /* Skip over any white space at start of string */
 187
 188         while (isspace((int)*string)) {
 189                 string++;
 190         }
 191
 192         /* End of string? return 0 */
 193
 194         if (*string == 0) {
 195                 return_ACPI_STATUS(AE_OK);
 196         }
 197
 198         /*
 199          * 1) The "0x" prefix indicates base 16. Per the ACPI specification,
 200          * the "0x" prefix is only allowed for implicit (non-strict) conversions.
 201          * However, we always allow it for compatibility with older ACPICA.
 202          */
 203         if ((*string == ACPI_ASCII_ZERO) &&
 204             (tolower((int)*(string + 1)) == 'x')) {
 205                 string += 2;    /* Go past the 0x */
 206                 if (*string == 0) {
 207                         return_ACPI_STATUS(AE_OK);      /* Return value 0 */
 208                 }
 209
 210                 base = 16;
 211         }
 212
 213         /* 2) Force to base 16 (implicit conversion case) */
 214
 215         else if (flags & ACPI_STRTOUL_BASE16) {
 216                 base = 16;
 217         }
 218
 219         /* 3) Default fallback is to Base 10 */
 220
 221         else {
 222                 base = 10;
 223         }
 224
 225         /* Skip all leading zeros */
 226
 227         while (*string == ACPI_ASCII_ZERO) {
 228                 string++;
 229                 if (*string == 0) {
 230                         return_ACPI_STATUS(AE_OK);      /* Return value 0 */
 231                 }
 232         }
 233
 234         /* Perform the base 16 or 10 conversion */
 235
 236         if (base == 16) {
 237                 *return_value = acpi_ut_strtoul_base16(string, flags);
 238         } else {
 239                 *return_value = acpi_ut_strtoul_base10(string, flags);
 240         }
 241
 242         return_ACPI_STATUS(status);
 243 }
 244
 245 /*******************************************************************************
 246  *
 247  * FUNCTION:    acpi_ut_strtoul_base10
 248  *
 249  * PARAMETERS:  string                  - Null terminated input string
 250  *              flags                   - Conversion info
 251  *
 252  * RETURN:      64-bit converted integer
 253  *
 254  * DESCRIPTION: Performs a base 10 conversion of the input string to an
 255  *              integer value, either 32 or 64 bits.
 256  *              Note: String must be valid and non-null.
 257  *
 258  ******************************************************************************/
 259
 260 static u64 acpi_ut_strtoul_base10(char *string, u32 flags)
 261 {
 262         int ascii_digit;
 263         u64 next_value;
 264         u64 return_value = 0;
 265
 266         /* Main loop: convert each ASCII byte in the input string */
 267
 268         while (*string) {
 269                 ascii_digit = *string;
 270                 if (!isdigit(ascii_digit)) {
 271
 272                         /* Not ASCII 0-9, terminate */
 273
 274                         goto exit;
 275                 }
 276
 277                 /* Convert and insert (add) the decimal digit */
 278
 279                 next_value =
 280                     (return_value * 10) + (ascii_digit - ACPI_ASCII_ZERO);
 281
 282                 /* Check for overflow (32 or 64 bit) - return current converted value */
 283
 284                 if (((flags & ACPI_STRTOUL_32BIT) && (next_value > ACPI_UINT32_MAX)) || (next_value < return_value)) {  /* 64-bit overflow case */
 285                         goto exit;
 286                 }
 287
 288                 return_value = next_value;
 289                 string++;
 290         }
 291
 292 exit:
 293         return (return_value);
 294 }
 295
 296 /*******************************************************************************
 297  *
 298  * FUNCTION:    acpi_ut_strtoul_base16
 299  *
 300  * PARAMETERS:  string                  - Null terminated input string
 301  *              flags                   - conversion info
 302  *
 303  * RETURN:      64-bit converted integer
 304  *
 305  * DESCRIPTION: Performs a base 16 conversion of the input string to an
 306  *              integer value, either 32 or 64 bits.
 307  *              Note: String must be valid and non-null.
 308  *
 309  ******************************************************************************/
 310
 311 static u64 acpi_ut_strtoul_base16(char *string, u32 flags)
 312 {
 313         int ascii_digit;
 314         u32 valid_digits = 1;
 315         u64 return_value = 0;
 316
 317         /* Main loop: convert each ASCII byte in the input string */
 318
 319         while (*string) {
 320
 321                 /* Check for overflow (32 or 64 bit) - return current converted value */
 322
 323                 if ((valid_digits > 16) ||
 324                     ((valid_digits > 8) && (flags & ACPI_STRTOUL_32BIT))) {
 325                         goto exit;
 326                 }
 327
 328                 ascii_digit = *string;
 329                 if (!isxdigit(ascii_digit)) {
 330
 331                         /* Not Hex ASCII A-F, a-f, or 0-9, terminate */
 332
 333                         goto exit;
 334                 }
 335
 336                 /* Convert and insert the hex digit */
 337
 338                 return_value =
 339                     (return_value << 4) |
 340                     acpi_ut_ascii_char_to_hex(ascii_digit);
 341
 342                 string++;
 343                 valid_digits++;
 344         }
 345
 346 exit:
 347         return (return_value);
 348 }