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Unified Diff: fusl/src/string/strstr.c

Issue 1714623002: [fusl] clang-format fusl (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: headers too Created 4 years, 10 months ago
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Index: fusl/src/string/strstr.c
diff --git a/fusl/src/string/strstr.c b/fusl/src/string/strstr.c
index cd0691275b2e4880853837738a1569ad1d06fc80..f4d87d71bded27a567ebdde04ced2c153a615f8c 100644
--- a/fusl/src/string/strstr.c
+++ b/fusl/src/string/strstr.c
@@ -1,155 +1,179 @@
#include <string.h>
#include <stdint.h>
-static char *twobyte_strstr(const unsigned char *h, const unsigned char *n)
-{
- uint16_t nw = n[0]<<8 | n[1], hw = h[0]<<8 | h[1];
- for (h++; *h && hw != nw; hw = hw<<8 | *++h);
- return *h ? (char *)h-1 : 0;
+static char* twobyte_strstr(const unsigned char* h, const unsigned char* n) {
+ uint16_t nw = n[0] << 8 | n[1], hw = h[0] << 8 | h[1];
+ for (h++; *h && hw != nw; hw = hw << 8 | *++h)
+ ;
+ return *h ? (char*)h - 1 : 0;
}
-static char *threebyte_strstr(const unsigned char *h, const unsigned char *n)
-{
- uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8;
- uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8;
- for (h+=2; *h && hw != nw; hw = (hw|*++h)<<8);
- return *h ? (char *)h-2 : 0;
+static char* threebyte_strstr(const unsigned char* h, const unsigned char* n) {
+ uint32_t nw = n[0] << 24 | n[1] << 16 | n[2] << 8;
+ uint32_t hw = h[0] << 24 | h[1] << 16 | h[2] << 8;
+ for (h += 2; *h && hw != nw; hw = (hw | *++h) << 8)
+ ;
+ return *h ? (char*)h - 2 : 0;
}
-static char *fourbyte_strstr(const unsigned char *h, const unsigned char *n)
-{
- uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8 | n[3];
- uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8 | h[3];
- for (h+=3; *h && hw != nw; hw = hw<<8 | *++h);
- return *h ? (char *)h-3 : 0;
+static char* fourbyte_strstr(const unsigned char* h, const unsigned char* n) {
+ uint32_t nw = n[0] << 24 | n[1] << 16 | n[2] << 8 | n[3];
+ uint32_t hw = h[0] << 24 | h[1] << 16 | h[2] << 8 | h[3];
+ for (h += 3; *h && hw != nw; hw = hw << 8 | *++h)
+ ;
+ return *h ? (char*)h - 3 : 0;
}
-#define MAX(a,b) ((a)>(b)?(a):(b))
-#define MIN(a,b) ((a)<(b)?(a):(b))
-
-#define BITOP(a,b,op) \
- ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
-
-static char *twoway_strstr(const unsigned char *h, const unsigned char *n)
-{
- const unsigned char *z;
- size_t l, ip, jp, k, p, ms, p0, mem, mem0;
- size_t byteset[32 / sizeof(size_t)] = { 0 };
- size_t shift[256];
-
- /* Computing length of needle and fill shift table */
- for (l=0; n[l] && h[l]; l++)
- BITOP(byteset, n[l], |=), shift[n[l]] = l+1;
- if (n[l]) return 0; /* hit the end of h */
-
- /* Compute maximal suffix */
- ip = -1; jp = 0; k = p = 1;
- while (jp+k<l) {
- if (n[ip+k] == n[jp+k]) {
- if (k == p) {
- jp += p;
- k = 1;
- } else k++;
- } else if (n[ip+k] > n[jp+k]) {
- jp += k;
- k = 1;
- p = jp - ip;
- } else {
- ip = jp++;
- k = p = 1;
- }
- }
- ms = ip;
- p0 = p;
-
- /* And with the opposite comparison */
- ip = -1; jp = 0; k = p = 1;
- while (jp+k<l) {
- if (n[ip+k] == n[jp+k]) {
- if (k == p) {
- jp += p;
- k = 1;
- } else k++;
- } else if (n[ip+k] < n[jp+k]) {
- jp += k;
- k = 1;
- p = jp - ip;
- } else {
- ip = jp++;
- k = p = 1;
- }
- }
- if (ip+1 > ms+1) ms = ip;
- else p = p0;
-
- /* Periodic needle? */
- if (memcmp(n, n+p, ms+1)) {
- mem0 = 0;
- p = MAX(ms, l-ms-1) + 1;
- } else mem0 = l-p;
- mem = 0;
-
- /* Initialize incremental end-of-haystack pointer */
- z = h;
-
- /* Search loop */
- for (;;) {
- /* Update incremental end-of-haystack pointer */
- if (z-h < l) {
- /* Fast estimate for MIN(l,63) */
- size_t grow = l | 63;
- const unsigned char *z2 = memchr(z, 0, grow);
- if (z2) {
- z = z2;
- if (z-h < l) return 0;
- } else z += grow;
- }
-
- /* Check last byte first; advance by shift on mismatch */
- if (BITOP(byteset, h[l-1], &)) {
- k = l-shift[h[l-1]];
- //printf("adv by %zu (on %c) at [%s] (%zu;l=%zu)\n", k, h[l-1], h, shift[h[l-1]], l);
- if (k) {
- if (mem0 && mem && k < p) k = l-p;
- h += k;
- mem = 0;
- continue;
- }
- } else {
- h += l;
- mem = 0;
- continue;
- }
-
- /* Compare right half */
- for (k=MAX(ms+1,mem); n[k] && n[k] == h[k]; k++);
- if (n[k]) {
- h += k-ms;
- mem = 0;
- continue;
- }
- /* Compare left half */
- for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
- if (k <= mem) return (char *)h;
- h += p;
- mem = mem0;
- }
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+#define BITOP(a, b, op) \
+ ((a)[(size_t)(b) / (8 * sizeof *(a))] op(size_t) 1 \
+ << ((size_t)(b) % (8 * sizeof *(a))))
+
+static char* twoway_strstr(const unsigned char* h, const unsigned char* n) {
+ const unsigned char* z;
+ size_t l, ip, jp, k, p, ms, p0, mem, mem0;
+ size_t byteset[32 / sizeof(size_t)] = {0};
+ size_t shift[256];
+
+ /* Computing length of needle and fill shift table */
+ for (l = 0; n[l] && h[l]; l++)
+ BITOP(byteset, n[l], |=), shift[n[l]] = l + 1;
+ if (n[l])
+ return 0; /* hit the end of h */
+
+ /* Compute maximal suffix */
+ ip = -1;
+ jp = 0;
+ k = p = 1;
+ while (jp + k < l) {
+ if (n[ip + k] == n[jp + k]) {
+ if (k == p) {
+ jp += p;
+ k = 1;
+ } else
+ k++;
+ } else if (n[ip + k] > n[jp + k]) {
+ jp += k;
+ k = 1;
+ p = jp - ip;
+ } else {
+ ip = jp++;
+ k = p = 1;
+ }
+ }
+ ms = ip;
+ p0 = p;
+
+ /* And with the opposite comparison */
+ ip = -1;
+ jp = 0;
+ k = p = 1;
+ while (jp + k < l) {
+ if (n[ip + k] == n[jp + k]) {
+ if (k == p) {
+ jp += p;
+ k = 1;
+ } else
+ k++;
+ } else if (n[ip + k] < n[jp + k]) {
+ jp += k;
+ k = 1;
+ p = jp - ip;
+ } else {
+ ip = jp++;
+ k = p = 1;
+ }
+ }
+ if (ip + 1 > ms + 1)
+ ms = ip;
+ else
+ p = p0;
+
+ /* Periodic needle? */
+ if (memcmp(n, n + p, ms + 1)) {
+ mem0 = 0;
+ p = MAX(ms, l - ms - 1) + 1;
+ } else
+ mem0 = l - p;
+ mem = 0;
+
+ /* Initialize incremental end-of-haystack pointer */
+ z = h;
+
+ /* Search loop */
+ for (;;) {
+ /* Update incremental end-of-haystack pointer */
+ if (z - h < l) {
+ /* Fast estimate for MIN(l,63) */
+ size_t grow = l | 63;
+ const unsigned char* z2 = memchr(z, 0, grow);
+ if (z2) {
+ z = z2;
+ if (z - h < l)
+ return 0;
+ } else
+ z += grow;
+ }
+
+ /* Check last byte first; advance by shift on mismatch */
+ if (BITOP(byteset, h[l - 1], &)) {
+ k = l - shift[h[l - 1]];
+ // printf("adv by %zu (on %c) at [%s] (%zu;l=%zu)\n", k, h[l-1], h,
+ // shift[h[l-1]], l);
+ if (k) {
+ if (mem0 && mem && k < p)
+ k = l - p;
+ h += k;
+ mem = 0;
+ continue;
+ }
+ } else {
+ h += l;
+ mem = 0;
+ continue;
+ }
+
+ /* Compare right half */
+ for (k = MAX(ms + 1, mem); n[k] && n[k] == h[k]; k++)
+ ;
+ if (n[k]) {
+ h += k - ms;
+ mem = 0;
+ continue;
+ }
+ /* Compare left half */
+ for (k = ms + 1; k > mem && n[k - 1] == h[k - 1]; k--)
+ ;
+ if (k <= mem)
+ return (char*)h;
+ h += p;
+ mem = mem0;
+ }
}
-char *strstr(const char *h, const char *n)
-{
- /* Return immediately on empty needle */
- if (!n[0]) return (char *)h;
-
- /* Use faster algorithms for short needles */
- h = strchr(h, *n);
- if (!h || !n[1]) return (char *)h;
- if (!h[1]) return 0;
- if (!n[2]) return twobyte_strstr((void *)h, (void *)n);
- if (!h[2]) return 0;
- if (!n[3]) return threebyte_strstr((void *)h, (void *)n);
- if (!h[3]) return 0;
- if (!n[4]) return fourbyte_strstr((void *)h, (void *)n);
-
- return twoway_strstr((void *)h, (void *)n);
+char* strstr(const char* h, const char* n) {
+ /* Return immediately on empty needle */
+ if (!n[0])
+ return (char*)h;
+
+ /* Use faster algorithms for short needles */
+ h = strchr(h, *n);
+ if (!h || !n[1])
+ return (char*)h;
+ if (!h[1])
+ return 0;
+ if (!n[2])
+ return twobyte_strstr((void*)h, (void*)n);
+ if (!h[2])
+ return 0;
+ if (!n[3])
+ return threebyte_strstr((void*)h, (void*)n);
+ if (!h[3])
+ return 0;
+ if (!n[4])
+ return fourbyte_strstr((void*)h, (void*)n);
+
+ return twoway_strstr((void*)h, (void*)n);
}

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