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); |
} |