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Make improvements
- Invent openatemp() API - Invent O_UNLINK open flag - Introduce getenv_secure() API - Remove `git pull` from cosmocc - Fix utimes() when path is NULL - Fix mktemp() to never return NULL - Fix utimensat() UTIME_OMIT on XNU - Improve utimensat() code for RHEL5 - Turn `argv[0]` C:/ to /C/ on Windows - Introduce tmpnam() and tmpnam_r() APIs - Fix more const issues with internal APIs - Permit utimes() on WIN32 in O_RDONLY mode - Fix fdopendir() to check fd is a directory - Fix recent crash regression in landlock make - Fix futimens(AT_FDCWD, NULL) to return EBADF - Use workaround so `make -j` doesn't fork bomb - Rename dontdiscard to __wur (just like glibc) - Fix st_size for WIN32 symlinks containing UTF-8 - Introduce stdio ext APIs needed by GNU coreutils - Fix lstat() on WIN32 for symlinks to directories - Move some constants from normalize.inc to limits.h - Fix segv with memchr() and memcmp() overlapping page - Implement POSIX fflush() behavior for reader streams - Implement AT_SYMLINK_NOFOLLOW for utimensat() on WIN32 - Don't change read-only status of existing files on WIN32 - Correctly handle `0x[^[:xdigit:]]` case in strtol() functions
This commit is contained in:
Justine Tunney
parent
8596e83cce
commit
f531acc8f9
297 changed files with 1920 additions and 1681 deletions
115
libc/str/bcmp.c
115
libc/str/bcmp.c
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@ -16,128 +16,15 @@
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/intrin/likely.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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typedef uint64_t xmm_t __attribute__((__vector_size__(16), __aligned__(1)));
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#if !defined(__chibicc__)
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static int bcmp_sse(const char *p, const char *q, size_t n) {
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xmm_t a;
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while (n > 32) {
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a = *(const xmm_t *)p ^ *(const xmm_t *)q;
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if (a[0] | a[1]) return 1;
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p += 16;
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q += 16;
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n -= 16;
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}
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a = (*(const xmm_t *)p ^ *(const xmm_t *)q) |
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(*(const xmm_t *)(p + n - 16) ^ *(const xmm_t *)(q + n - 16));
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return !!(a[0] | a[1]);
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}
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#endif
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#if defined(__x86_64__) && !defined(__chibicc__)
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_Microarchitecture("avx") static int bcmp_avx(const char *p, const char *q,
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size_t n) {
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xmm_t a, b, c, d;
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if (n > 32) {
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if (n >= 16 + 64) {
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do {
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a = ((const xmm_t *)p)[0] ^ ((const xmm_t *)q)[0];
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b = ((const xmm_t *)p)[1] ^ ((const xmm_t *)q)[1];
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c = ((const xmm_t *)p)[2] ^ ((const xmm_t *)q)[2];
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d = ((const xmm_t *)p)[3] ^ ((const xmm_t *)q)[3];
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a = a | b | c | d;
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if (a[0] | a[1]) return 1;
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p += 64;
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q += 64;
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n -= 64;
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} while (n >= 16 + 64);
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}
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while (n > 16 + 16) {
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a = *(const xmm_t *)p ^ *(const xmm_t *)q;
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if (a[0] | a[1]) return 1;
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p += 16;
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q += 16;
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n -= 16;
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}
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}
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a = (*(const xmm_t *)p ^ *(const xmm_t *)q) |
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(*(const xmm_t *)(p + n - 16) ^ *(const xmm_t *)(q + n - 16));
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return !!(a[0] | a[1]);
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}
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#endif
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/**
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* Tests inequality of first 𝑛 bytes of 𝑝 and 𝑞.
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*
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* bcmp n=0 992 picoseconds
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* bcmp n=1 992 ps/byte 984 mb/s
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* bcmp n=2 661 ps/byte 1,476 mb/s
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* bcmp n=3 441 ps/byte 2,214 mb/s
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* bcmp n=4 330 ps/byte 2,952 mb/s
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* bcmp n=5 264 ps/byte 3,690 mb/s
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* bcmp n=6 165 ps/byte 5,905 mb/s
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* bcmp n=7 189 ps/byte 5,166 mb/s
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* bcmp n=8 124 ps/byte 7,873 mb/s
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* bcmp n=9 183 ps/byte 5,314 mb/s
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* bcmp n=15 110 ps/byte 8,857 mb/s
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* bcmp n=16 62 ps/byte 15,746 mb/s
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* bcmp n=17 175 ps/byte 5,577 mb/s
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* bcmp n=31 96 ps/byte 10,169 mb/s
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* bcmp n=32 93 ps/byte 10,497 mb/s
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* bcmp n=33 80 ps/byte 12,179 mb/s
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* bcmp n=80 37 ps/byte 26,244 mb/s
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* bcmp n=128 36 ps/byte 26,994 mb/s
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* bcmp n=256 27 ps/byte 35,992 mb/s
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* bcmp n=16384 19 ps/byte 49,411 mb/s
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* bcmp n=32768 27 ps/byte 34,914 mb/s
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* bcmp n=131072 30 ps/byte 32,303 mb/s
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*
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* @return 0 if a and b have equal contents, otherwise nonzero
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* @see timingsafe_bcmp()
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* @asyncsignalsafe
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*/
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int bcmp(const void *a, const void *b, size_t n) {
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int c;
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uint32_t i, j;
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uint64_t x, y;
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const char *p, *q;
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if ((p = a) == (q = b)) return 0;
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if (!IsTiny()) {
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if (n <= 16) {
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if (n >= 8) {
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__builtin_memcpy(&x, p, 8);
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__builtin_memcpy(&y, q, 8);
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if (x ^ y) return 1;
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__builtin_memcpy(&x, p + n - 8, 8);
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__builtin_memcpy(&y, q + n - 8, 8);
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return !!(x ^ y);
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} else if (n >= 4) {
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__builtin_memcpy(&i, p, 4);
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__builtin_memcpy(&j, q, 4);
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if (i ^ j) return 1;
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__builtin_memcpy(&i, p + n - 4, 4);
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__builtin_memcpy(&j, q + n - 4, 4);
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return !!(i ^ j);
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}
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#ifndef __chibicc__
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#ifdef __x86_64__
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} else if (LIKELY(X86_HAVE(AVX))) {
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return bcmp_avx(p, q, n);
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#endif
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} else {
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return bcmp_sse(p, q, n);
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#endif
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}
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}
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while (n--) {
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if ((c = p[n] ^ q[n])) {
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return c;
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}
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}
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return 0;
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return memcmp(a, b, n);
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}
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