X-Git-Url: http://woldlab.caltech.edu/gitweb/?p=samtools.git;a=blobdiff_plain;f=kstring.c;h=b2a0dab03c36f616c50aa6e5b79709134855db8e;hp=dc20faeac9fef21c88813c34f9f42ac6c69d449d;hb=d59366b97f0e6a0cbb0dfcdc5679f0ed88c8fe1e;hpb=b27e00385f41769d03a8cca4dbd71275fc9fa906

diff --git a/kstring.c b/kstring.c
index dc20fae..b2a0dab 100644
--- a/kstring.c
+++ b/kstring.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <ctype.h>
 #include <string.h>
+#include <stdint.h>
 #include "kstring.h"
 
 int ksprintf(kstring_t *s, const char *fmt, ...)
@@ -23,6 +24,32 @@ int ksprintf(kstring_t *s, const char *fmt, ...)
 	return l;
 }
 
+char *kstrtok(const char *str, const char *sep, ks_tokaux_t *aux)
+{
+	const char *p, *start;
+	if (sep) { // set up the table
+		if (str == 0 && (aux->tab[0]&1)) return 0; // no need to set up if we have finished
+		aux->finished = 0;
+		if (sep[1]) {
+			aux->sep = -1;
+			aux->tab[0] = aux->tab[1] = aux->tab[2] = aux->tab[3] = 0;
+			for (p = sep; *p; ++p) aux->tab[*p>>6] |= 1ull<<(*p&0x3f);
+		} else aux->sep = sep[0];
+	}
+	if (aux->finished) return 0;
+	else if (str) aux->p = str - 1, aux->finished = 0;
+	if (aux->sep < 0) {
+		for (p = start = aux->p + 1; *p; ++p)
+			if (aux->tab[*p>>6]>>(*p&0x3f)&1) break;
+	} else {
+		for (p = start = aux->p + 1; *p; ++p)
+			if (*p == aux->sep) break;
+	}
+	aux->p = p; // end of token
+	if (*p == 0) aux->finished = 1; // no more tokens
+	return (char*)start;
+}
+
 // s MUST BE a null terminated string; l = strlen(s)
 int ksplit_core(char *s, int delimiter, int *_max, int **_offsets)
 {
@@ -61,12 +88,96 @@ int ksplit_core(char *s, int delimiter, int *_max, int **_offsets)
 	return n;
 }
 
+/**********************
+ * Boyer-Moore search *
+ **********************/
+
+typedef unsigned char ubyte_t;
+
+// reference: http://www-igm.univ-mlv.fr/~lecroq/string/node14.html
+static int *ksBM_prep(const ubyte_t *pat, int m)
+{
+	int i, *suff, *prep, *bmGs, *bmBc;
+	prep = calloc(m + 256, sizeof(int));
+	bmGs = prep; bmBc = prep + m;
+	{ // preBmBc()
+		for (i = 0; i < 256; ++i) bmBc[i] = m;
+		for (i = 0; i < m - 1; ++i) bmBc[pat[i]] = m - i - 1;
+	}
+	suff = calloc(m, sizeof(int));
+	{ // suffixes()
+		int f = 0, g;
+		suff[m - 1] = m;
+		g = m - 1;
+		for (i = m - 2; i >= 0; --i) {
+			if (i > g && suff[i + m - 1 - f] < i - g)
+				suff[i] = suff[i + m - 1 - f];
+			else {
+				if (i < g) g = i;
+				f = i;
+				while (g >= 0 && pat[g] == pat[g + m - 1 - f]) --g;
+				suff[i] = f - g;
+			}
+		}
+	}
+	{ // preBmGs()
+		int j = 0;
+		for (i = 0; i < m; ++i) bmGs[i] = m;
+		for (i = m - 1; i >= 0; --i)
+			if (suff[i] == i + 1)
+				for (; j < m - 1 - i; ++j)
+					if (bmGs[j] == m)
+						bmGs[j] = m - 1 - i;
+		for (i = 0; i <= m - 2; ++i)
+			bmGs[m - 1 - suff[i]] = m - 1 - i;
+	}
+	free(suff);
+	return prep;
+}
+
+void *kmemmem(const void *_str, int n, const void *_pat, int m, int **_prep)
+{
+	int i, j, *prep = 0, *bmGs, *bmBc;
+	const ubyte_t *str, *pat;
+	str = (const ubyte_t*)_str; pat = (const ubyte_t*)_pat;
+	prep = (_prep == 0 || *_prep == 0)? ksBM_prep(pat, m) : *_prep;
+	if (_prep && *_prep == 0) *_prep = prep;
+	bmGs = prep; bmBc = prep + m;
+	j = 0;
+	while (j <= n - m) {
+		for (i = m - 1; i >= 0 && pat[i] == str[i+j]; --i);
+		if (i >= 0) {
+			int max = bmBc[str[i+j]] - m + 1 + i;
+			if (max < bmGs[i]) max = bmGs[i];
+			j += max;
+		} else return (void*)(str + j);
+	}
+	if (_prep == 0) free(prep);
+	return 0;
+}
+
+char *kstrstr(const char *str, const char *pat, int **_prep)
+{
+	return (char*)kmemmem(str, strlen(str), pat, strlen(pat), _prep);
+}
+
+char *kstrnstr(const char *str, const char *pat, int n, int **_prep)
+{
+	return (char*)kmemmem(str, n, pat, strlen(pat), _prep);
+}
+
+/***********************
+ * The main() function *
+ ***********************/
+
 #ifdef KSTRING_MAIN
 #include <stdio.h>
 int main()
 {
 	kstring_t *s;
 	int *fields, n, i;
+	ks_tokaux_t aux;
+	char *p;
 	s = (kstring_t*)calloc(1, sizeof(kstring_t));
 	// test ksprintf()
 	ksprintf(s, " abcdefg:    %d ", 100);
@@ -75,7 +186,27 @@ int main()
 	fields = ksplit(s, 0, &n);
 	for (i = 0; i < n; ++i)
 		printf("field[%d] = '%s'\n", i, s->s + fields[i]);
-	free(s);
+	// test kstrtok()
+	s->l = 0;
+	for (p = kstrtok("ab:cde:fg/hij::k", ":/", &aux); p; p = kstrtok(0, 0, &aux)) {
+		kputsn(p, aux.p - p, s);
+		kputc('\n', s);
+	}
+	printf("%s", s->s);
+	// free
+	free(s->s); free(s); free(fields);
+
+	{
+		static char *str = "abcdefgcdgcagtcakcdcd";
+		static char *pat = "cd";
+		char *ret, *s = str;
+		int *prep = 0;
+		while ((ret = kstrstr(s, pat, &prep)) != 0) {
+			printf("match: %s\n", ret);
+			s = ret + prep[0];
+		}
+		free(prep);
+	}
 	return 0;
 }
 #endif