Add comment to fix -Wfallthrough warning
[official-gcc.git] / libsanitizer / sanitizer_common / sanitizer_libc.cc
blob82d37675e479421afed9704ab06963918c510076
1 //===-- sanitizer_libc.cc -------------------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is shared between AddressSanitizer and ThreadSanitizer
9 // run-time libraries. See sanitizer_libc.h for details.
10 //===----------------------------------------------------------------------===//
12 #include "sanitizer_allocator_internal.h"
13 #include "sanitizer_common.h"
14 #include "sanitizer_libc.h"
16 namespace __sanitizer {
18 s64 internal_atoll(const char *nptr) {
19 return internal_simple_strtoll(nptr, nullptr, 10);
22 void *internal_memchr(const void *s, int c, uptr n) {
23 const char *t = (const char *)s;
24 for (uptr i = 0; i < n; ++i, ++t)
25 if (*t == c)
26 return reinterpret_cast<void *>(const_cast<char *>(t));
27 return nullptr;
30 void *internal_memrchr(const void *s, int c, uptr n) {
31 const char *t = (const char *)s;
32 void *res = nullptr;
33 for (uptr i = 0; i < n; ++i, ++t) {
34 if (*t == c) res = reinterpret_cast<void *>(const_cast<char *>(t));
36 return res;
39 int internal_memcmp(const void* s1, const void* s2, uptr n) {
40 const char *t1 = (const char *)s1;
41 const char *t2 = (const char *)s2;
42 for (uptr i = 0; i < n; ++i, ++t1, ++t2)
43 if (*t1 != *t2)
44 return *t1 < *t2 ? -1 : 1;
45 return 0;
48 void *internal_memcpy(void *dest, const void *src, uptr n) {
49 char *d = (char*)dest;
50 const char *s = (const char *)src;
51 for (uptr i = 0; i < n; ++i)
52 d[i] = s[i];
53 return dest;
56 void *internal_memmove(void *dest, const void *src, uptr n) {
57 char *d = (char*)dest;
58 const char *s = (const char *)src;
59 sptr i, signed_n = (sptr)n;
60 CHECK_GE(signed_n, 0);
61 if (d < s) {
62 for (i = 0; i < signed_n; ++i)
63 d[i] = s[i];
64 } else {
65 if (d > s && signed_n > 0)
66 for (i = signed_n - 1; i >= 0 ; --i) {
67 d[i] = s[i];
70 return dest;
73 // Semi-fast bzero for 16-aligned data. Still far from peak performance.
74 void internal_bzero_aligned16(void *s, uptr n) {
75 struct ALIGNED(16) S16 { u64 a, b; };
76 CHECK_EQ((reinterpret_cast<uptr>(s) | n) & 15, 0);
77 for (S16 *p = reinterpret_cast<S16*>(s), *end = p + n / 16; p < end; p++) {
78 p->a = p->b = 0;
79 // Make sure this does not become memset.
80 SanitizerBreakOptimization(nullptr);
84 void *internal_memset(void* s, int c, uptr n) {
85 // The next line prevents Clang from making a call to memset() instead of the
86 // loop below.
87 // FIXME: building the runtime with -ffreestanding is a better idea. However
88 // there currently are linktime problems due to PR12396.
89 char volatile *t = (char*)s;
90 for (uptr i = 0; i < n; ++i, ++t) {
91 *t = c;
93 return s;
96 uptr internal_strcspn(const char *s, const char *reject) {
97 uptr i;
98 for (i = 0; s[i]; i++) {
99 if (internal_strchr(reject, s[i]))
100 return i;
102 return i;
105 char* internal_strdup(const char *s) {
106 uptr len = internal_strlen(s);
107 char *s2 = (char*)InternalAlloc(len + 1);
108 internal_memcpy(s2, s, len);
109 s2[len] = 0;
110 return s2;
113 char* internal_strndup(const char *s, uptr n) {
114 uptr len = internal_strnlen(s, n);
115 char *s2 = (char*)InternalAlloc(len + 1);
116 internal_memcpy(s2, s, len);
117 s2[len] = 0;
118 return s2;
121 int internal_strcmp(const char *s1, const char *s2) {
122 while (true) {
123 unsigned c1 = *s1;
124 unsigned c2 = *s2;
125 if (c1 != c2) return (c1 < c2) ? -1 : 1;
126 if (c1 == 0) break;
127 s1++;
128 s2++;
130 return 0;
133 int internal_strncmp(const char *s1, const char *s2, uptr n) {
134 for (uptr i = 0; i < n; i++) {
135 unsigned c1 = *s1;
136 unsigned c2 = *s2;
137 if (c1 != c2) return (c1 < c2) ? -1 : 1;
138 if (c1 == 0) break;
139 s1++;
140 s2++;
142 return 0;
145 char* internal_strchr(const char *s, int c) {
146 while (true) {
147 if (*s == (char)c)
148 return const_cast<char *>(s);
149 if (*s == 0)
150 return nullptr;
151 s++;
155 char *internal_strchrnul(const char *s, int c) {
156 char *res = internal_strchr(s, c);
157 if (!res)
158 res = const_cast<char *>(s) + internal_strlen(s);
159 return res;
162 char *internal_strrchr(const char *s, int c) {
163 const char *res = nullptr;
164 for (uptr i = 0; s[i]; i++) {
165 if (s[i] == c) res = s + i;
167 return const_cast<char *>(res);
170 uptr internal_strlen(const char *s) {
171 uptr i = 0;
172 while (s[i]) i++;
173 return i;
176 uptr internal_strlcat(char *dst, const char *src, uptr maxlen) {
177 const uptr srclen = internal_strlen(src);
178 const uptr dstlen = internal_strnlen(dst, maxlen);
179 if (dstlen == maxlen) return maxlen + srclen;
180 if (srclen < maxlen - dstlen) {
181 internal_memmove(dst + dstlen, src, srclen + 1);
182 } else {
183 internal_memmove(dst + dstlen, src, maxlen - dstlen - 1);
184 dst[maxlen - 1] = '\0';
186 return dstlen + srclen;
189 char *internal_strncat(char *dst, const char *src, uptr n) {
190 uptr len = internal_strlen(dst);
191 uptr i;
192 for (i = 0; i < n && src[i]; i++)
193 dst[len + i] = src[i];
194 dst[len + i] = 0;
195 return dst;
198 uptr internal_strlcpy(char *dst, const char *src, uptr maxlen) {
199 const uptr srclen = internal_strlen(src);
200 if (srclen < maxlen) {
201 internal_memmove(dst, src, srclen + 1);
202 } else if (maxlen != 0) {
203 internal_memmove(dst, src, maxlen - 1);
204 dst[maxlen - 1] = '\0';
206 return srclen;
209 char *internal_strncpy(char *dst, const char *src, uptr n) {
210 uptr i;
211 for (i = 0; i < n && src[i]; i++)
212 dst[i] = src[i];
213 internal_memset(dst + i, '\0', n - i);
214 return dst;
217 uptr internal_strnlen(const char *s, uptr maxlen) {
218 uptr i = 0;
219 while (i < maxlen && s[i]) i++;
220 return i;
223 char *internal_strstr(const char *haystack, const char *needle) {
224 // This is O(N^2), but we are not using it in hot places.
225 uptr len1 = internal_strlen(haystack);
226 uptr len2 = internal_strlen(needle);
227 if (len1 < len2) return nullptr;
228 for (uptr pos = 0; pos <= len1 - len2; pos++) {
229 if (internal_memcmp(haystack + pos, needle, len2) == 0)
230 return const_cast<char *>(haystack) + pos;
232 return nullptr;
235 uptr internal_wcslen(const wchar_t *s) {
236 uptr i = 0;
237 while (s[i]) i++;
238 return i;
241 s64 internal_simple_strtoll(const char *nptr, char **endptr, int base) {
242 CHECK_EQ(base, 10);
243 while (IsSpace(*nptr)) nptr++;
244 int sgn = 1;
245 u64 res = 0;
246 bool have_digits = false;
247 char *old_nptr = const_cast<char *>(nptr);
248 if (*nptr == '+') {
249 sgn = 1;
250 nptr++;
251 } else if (*nptr == '-') {
252 sgn = -1;
253 nptr++;
255 while (IsDigit(*nptr)) {
256 res = (res <= UINT64_MAX / 10) ? res * 10 : UINT64_MAX;
257 int digit = ((*nptr) - '0');
258 res = (res <= UINT64_MAX - digit) ? res + digit : UINT64_MAX;
259 have_digits = true;
260 nptr++;
262 if (endptr) {
263 *endptr = (have_digits) ? const_cast<char *>(nptr) : old_nptr;
265 if (sgn > 0) {
266 return (s64)(Min((u64)INT64_MAX, res));
267 } else {
268 return (res > INT64_MAX) ? INT64_MIN : ((s64)res * -1);
272 bool mem_is_zero(const char *beg, uptr size) {
273 CHECK_LE(size, 1ULL << FIRST_32_SECOND_64(30, 40)); // Sanity check.
274 const char *end = beg + size;
275 uptr *aligned_beg = (uptr *)RoundUpTo((uptr)beg, sizeof(uptr));
276 uptr *aligned_end = (uptr *)RoundDownTo((uptr)end, sizeof(uptr));
277 uptr all = 0;
278 // Prologue.
279 for (const char *mem = beg; mem < (char*)aligned_beg && mem < end; mem++)
280 all |= *mem;
281 // Aligned loop.
282 for (; aligned_beg < aligned_end; aligned_beg++)
283 all |= *aligned_beg;
284 // Epilogue.
285 if ((char*)aligned_end >= beg)
286 for (const char *mem = (char*)aligned_end; mem < end; mem++)
287 all |= *mem;
288 return all == 0;
291 } // namespace __sanitizer