1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /*******************************************************************************
3 *
4 * Module Name: utstrsuppt - Support functions for string-to-integer conversion
5 *
6 ******************************************************************************/
7
8 #include <acpi/acpi.h>
9 #include "accommon.h"
10
11 #define _COMPONENT ACPI_UTILITIES
12 ACPI_MODULE_NAME("utstrsuppt")
13
14 /* Local prototypes */
15 static acpi_status
16 acpi_ut_insert_digit(u64 *accumulated_value, u32 base, int ascii_digit);
17
18 static acpi_status
19 acpi_ut_strtoul_multiply64(u64 multiplicand, u32 base, u64 *out_product);
20
21 static acpi_status acpi_ut_strtoul_add64(u64 addend1, u32 digit, u64 *out_sum);
22
23 /*******************************************************************************
24 *
25 * FUNCTION: acpi_ut_convert_octal_string
26 *
27 * PARAMETERS: string - Null terminated input string
28 * return_value_ptr - Where the converted value is returned
29 *
30 * RETURN: Status and 64-bit converted integer
31 *
32 * DESCRIPTION: Performs a base 8 conversion of the input string to an
33 * integer value, either 32 or 64 bits.
34 *
35 * NOTE: Maximum 64-bit unsigned octal value is 01777777777777777777777
36 * Maximum 32-bit unsigned octal value is 037777777777
37 *
38 ******************************************************************************/
39
40 acpi_status acpi_ut_convert_octal_string(char *string, u64 *return_value_ptr)
41 {
42 u64 accumulated_value = 0;
43 acpi_status status = AE_OK;
44
45 /* Convert each ASCII byte in the input string */
46
47 while (*string) {
48
49 /* Character must be ASCII 0-7, otherwise terminate with no error */
50
51 if (!(ACPI_IS_OCTAL_DIGIT(*string))) {
52 break;
53 }
54
55 /* Convert and insert this octal digit into the accumulator */
56
57 status = acpi_ut_insert_digit(&accumulated_value, 8, *string);
58 if (ACPI_FAILURE(status)) {
59 status = AE_OCTAL_OVERFLOW;
60 break;
61 }
62
63 string++;
64 }
65
66 /* Always return the value that has been accumulated */
67
68 *return_value_ptr = accumulated_value;
69 return (status);
70 }
71
72 /*******************************************************************************
73 *
74 * FUNCTION: acpi_ut_convert_decimal_string
75 *
76 * PARAMETERS: string - Null terminated input string
77 * return_value_ptr - Where the converted value is returned
78 *
79 * RETURN: Status and 64-bit converted integer
80 *
81 * DESCRIPTION: Performs a base 10 conversion of the input string to an
82 * integer value, either 32 or 64 bits.
83 *
84 * NOTE: Maximum 64-bit unsigned decimal value is 18446744073709551615
85 * Maximum 32-bit unsigned decimal value is 4294967295
86 *
87 ******************************************************************************/
88
89 acpi_status acpi_ut_convert_decimal_string(char *string, u64 *return_value_ptr)
90 {
91 u64 accumulated_value = 0;
92 acpi_status status = AE_OK;
93
94 /* Convert each ASCII byte in the input string */
95
96 while (*string) {
97
98 /* Character must be ASCII 0-9, otherwise terminate with no error */
99
100 if (!isdigit(*string)) {
101 break;
102 }
103
104 /* Convert and insert this decimal digit into the accumulator */
105
106 status = acpi_ut_insert_digit(&accumulated_value, 10, *string);
107 if (ACPI_FAILURE(status)) {
108 status = AE_DECIMAL_OVERFLOW;
109 break;
110 }
111
112 string++;
113 }
114
115 /* Always return the value that has been accumulated */
116
117 *return_value_ptr = accumulated_value;
118 return (status);
119 }
120
121 /*******************************************************************************
122 *
123 * FUNCTION: acpi_ut_convert_hex_string
124 *
125 * PARAMETERS: string - Null terminated input string
126 * return_value_ptr - Where the converted value is returned
127 *
128 * RETURN: Status and 64-bit converted integer
129 *
130 * DESCRIPTION: Performs a base 16 conversion of the input string to an
131 * integer value, either 32 or 64 bits.
132 *
133 * NOTE: Maximum 64-bit unsigned hex value is 0xFFFFFFFFFFFFFFFF
134 * Maximum 32-bit unsigned hex value is 0xFFFFFFFF
135 *
136 ******************************************************************************/
137
138 acpi_status acpi_ut_convert_hex_string(char *string, u64 *return_value_ptr)
139 {
140 u64 accumulated_value = 0;
141 acpi_status status = AE_OK;
142
143 /* Convert each ASCII byte in the input string */
144
145 while (*string) {
146
147 /* Must be ASCII A-F, a-f, or 0-9, otherwise terminate with no error */
148
149 if (!isxdigit(*string)) {
150 break;
151 }
152
153 /* Convert and insert this hex digit into the accumulator */
154
155 status = acpi_ut_insert_digit(&accumulated_value, 16, *string);
156 if (ACPI_FAILURE(status)) {
157 status = AE_HEX_OVERFLOW;
158 break;
159 }
160
161 string++;
162 }
163
164 /* Always return the value that has been accumulated */
165
166 *return_value_ptr = accumulated_value;
167 return (status);
168 }
169
170 /*******************************************************************************
171 *
172 * FUNCTION: acpi_ut_remove_leading_zeros
173 *
174 * PARAMETERS: string - Pointer to input ASCII string
175 *
176 * RETURN: Next character after any leading zeros. This character may be
177 * used by the caller to detect end-of-string.
178 *
179 * DESCRIPTION: Remove any leading zeros in the input string. Return the
180 * next character after the final ASCII zero to enable the caller
181 * to check for the end of the string (NULL terminator).
182 *
183 ******************************************************************************/
184
185 char acpi_ut_remove_leading_zeros(char **string)
186 {
187
188 while (**string == ACPI_ASCII_ZERO) {
189 *string += 1;
190 }
191
192 return (**string);
193 }
194
195 /*******************************************************************************
196 *
197 * FUNCTION: acpi_ut_remove_whitespace
198 *
199 * PARAMETERS: string - Pointer to input ASCII string
200 *
201 * RETURN: Next character after any whitespace. This character may be
202 * used by the caller to detect end-of-string.
203 *
204 * DESCRIPTION: Remove any leading whitespace in the input string. Return the
205 * next character after the final ASCII zero to enable the caller
206 * to check for the end of the string (NULL terminator).
207 *
208 ******************************************************************************/
209
210 char acpi_ut_remove_whitespace(char **string)
211 {
212
213 while (isspace((u8)**string)) {
214 *string += 1;
215 }
216
217 return (**string);
218 }
219
220 /*******************************************************************************
221 *
222 * FUNCTION: acpi_ut_detect_hex_prefix
223 *
224 * PARAMETERS: string - Pointer to input ASCII string
225 *
226 * RETURN: TRUE if a "0x" prefix was found at the start of the string
227 *
228 * DESCRIPTION: Detect and remove a hex "0x" prefix
229 *
230 ******************************************************************************/
231
232 u8 acpi_ut_detect_hex_prefix(char **string)
233 {
234 char *initial_position = *string;
235
236 acpi_ut_remove_hex_prefix(string);
237 if (*string != initial_position) {
238 return (TRUE); /* String is past leading 0x */
239 }
240
241 return (FALSE); /* Not a hex string */
242 }
243
244 /*******************************************************************************
245 *
246 * FUNCTION: acpi_ut_remove_hex_prefix
247 *
248 * PARAMETERS: string - Pointer to input ASCII string
249 *
250 * RETURN: none
251 *
252 * DESCRIPTION: Remove a hex "0x" prefix
253 *
254 ******************************************************************************/
255
256 void acpi_ut_remove_hex_prefix(char **string)
257 {
258 if ((**string == ACPI_ASCII_ZERO) &&
259 (tolower((int)*(*string + 1)) == 'x')) {
260 *string += 2; /* Go past the leading 0x */
261 }
262 }
263
264 /*******************************************************************************
265 *
266 * FUNCTION: acpi_ut_detect_octal_prefix
267 *
268 * PARAMETERS: string - Pointer to input ASCII string
269 *
270 * RETURN: True if an octal "0" prefix was found at the start of the
271 * string
272 *
273 * DESCRIPTION: Detect and remove an octal prefix (zero)
274 *
275 ******************************************************************************/
276
277 u8 acpi_ut_detect_octal_prefix(char **string)
278 {
279
280 if (**string == ACPI_ASCII_ZERO) {
281 *string += 1; /* Go past the leading 0 */
282 return (TRUE);
283 }
284
285 return (FALSE); /* Not an octal string */
286 }
287
288 /*******************************************************************************
289 *
290 * FUNCTION: acpi_ut_insert_digit
291 *
292 * PARAMETERS: accumulated_value - Current value of the integer value
293 * accumulator. The new value is
294 * returned here.
295 * base - Radix, either 8/10/16
296 * ascii_digit - ASCII single digit to be inserted
297 *
298 * RETURN: Status and result of the convert/insert operation. The only
299 * possible returned exception code is numeric overflow of
300 * either the multiply or add conversion operations.
301 *
302 * DESCRIPTION: Generic conversion and insertion function for all bases:
303 *
304 * 1) Multiply the current accumulated/converted value by the
305 * base in order to make room for the new character.
306 *
307 * 2) Convert the new character to binary and add it to the
308 * current accumulated value.
309 *
310 * Note: The only possible exception indicates an integer
311 * overflow (AE_NUMERIC_OVERFLOW)
312 *
313 ******************************************************************************/
314
315 static acpi_status
316 acpi_ut_insert_digit(u64 *accumulated_value, u32 base, int ascii_digit)
317 {
318 acpi_status status;
319 u64 product;
320
321 /* Make room in the accumulated value for the incoming digit */
322
323 status = acpi_ut_strtoul_multiply64(*accumulated_value, base, &product);
324 if (ACPI_FAILURE(status)) {
325 return (status);
326 }
327
328 /* Add in the new digit, and store the sum to the accumulated value */
329
330 status =
331 acpi_ut_strtoul_add64(product,
332 acpi_ut_ascii_char_to_hex(ascii_digit),
333 accumulated_value);
334
335 return (status);
336 }
337
338 /*******************************************************************************
339 *
340 * FUNCTION: acpi_ut_strtoul_multiply64
341 *
342 * PARAMETERS: multiplicand - Current accumulated converted integer
343 * base - Base/Radix
344 * out_product - Where the product is returned
345 *
346 * RETURN: Status and 64-bit product
347 *
348 * DESCRIPTION: Multiply two 64-bit values, with checking for 64-bit overflow as
349 * well as 32-bit overflow if necessary (if the current global
350 * integer width is 32).
351 *
352 ******************************************************************************/
353
354 static acpi_status
355 acpi_ut_strtoul_multiply64(u64 multiplicand, u32 base, u64 *out_product)
356 {
357 u64 product;
358 u64 quotient;
359
360 /* Exit if either operand is zero */
361
362 *out_product = 0;
363 if (!multiplicand || !base) {
364 return (AE_OK);
365 }
366
367 /*
368 * Check for 64-bit overflow before the actual multiplication.
369 *
370 * Notes: 64-bit division is often not supported on 32-bit platforms
371 * (it requires a library function), Therefore ACPICA has a local
372 * 64-bit divide function. Also, Multiplier is currently only used
373 * as the radix (8/10/16), to the 64/32 divide will always work.
374 */
375 acpi_ut_short_divide(ACPI_UINT64_MAX, base, "ient, NULL);
376 if (multiplicand > quotient) {
377 return (AE_NUMERIC_OVERFLOW);
378 }
379
380 product = multiplicand * base;
381
382 /* Check for 32-bit overflow if necessary */
383
384 if ((acpi_gbl_integer_bit_width == 32) && (product > ACPI_UINT32_MAX)) {
385 return (AE_NUMERIC_OVERFLOW);
386 }
387
388 *out_product = product;
389 return (AE_OK);
390 }
391
392 /*******************************************************************************
393 *
394 * FUNCTION: acpi_ut_strtoul_add64
395 *
396 * PARAMETERS: addend1 - Current accumulated converted integer
397 * digit - New hex value/char
398 * out_sum - Where sum is returned (Accumulator)
399 *
400 * RETURN: Status and 64-bit sum
401 *
402 * DESCRIPTION: Add two 64-bit values, with checking for 64-bit overflow as
403 * well as 32-bit overflow if necessary (if the current global
404 * integer width is 32).
405 *
406 ******************************************************************************/
407
408 static acpi_status acpi_ut_strtoul_add64(u64 addend1, u32 digit, u64 *out_sum)
409 {
410 u64 sum;
411
412 /* Check for 64-bit overflow before the actual addition */
413
414 if ((addend1 > 0) && (digit > (ACPI_UINT64_MAX - addend1))) {
415 return (AE_NUMERIC_OVERFLOW);
416 }
417
418 sum = addend1 + digit;
419
420 /* Check for 32-bit overflow if necessary */
421
422 if ((acpi_gbl_integer_bit_width == 32) && (sum > ACPI_UINT32_MAX)) {
423 return (AE_NUMERIC_OVERFLOW);
424 }
425
426 *out_sum = sum;
427 return (AE_OK);
428 }