| 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);
|
| }
|
|
|