X-Git-Url: http://woldlab.caltech.edu/gitweb/?p=pysam.git;a=blobdiff_plain;f=tabix%2Fkstring.c;fp=tabix%2Fkstring.c;h=e0203fa3e877604f53291b39ff6a2f273e6dff8f;hp=0000000000000000000000000000000000000000;hb=6a7c3f175b210cc16d09a5e8e4c1d47333dbe1c6;hpb=aa8ecff068edbb09a03bd874fce716e93e22e53c

diff --git a/tabix/kstring.c b/tabix/kstring.c
new file mode 100644
index 0000000..e0203fa
--- /dev/null
+++ b/tabix/kstring.c
@@ -0,0 +1,165 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdint.h>
+#include "kstring.h"
+
+int ksprintf(kstring_t *s, const char *fmt, ...)
+{
+	va_list ap;
+	int l;
+	va_start(ap, fmt);
+	l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap); // This line does not work with glibc 2.0. See `man snprintf'.
+	va_end(ap);
+	if (l + 1 > s->m - s->l) {
+		s->m = s->l + l + 2;
+		kroundup32(s->m);
+		s->s = (char*)realloc(s->s, s->m);
+		va_start(ap, fmt);
+		l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap);
+	}
+	va_end(ap);
+	s->l += l;
+	return l;
+}
+
+// s MUST BE a null terminated string; l = strlen(s)
+int ksplit_core(char *s, int delimiter, int *_max, int **_offsets)
+{
+	int i, n, max, last_char, last_start, *offsets, l;
+	n = 0; max = *_max; offsets = *_offsets;
+	l = strlen(s);
+	
+#define __ksplit_aux do {												\
+		if (_offsets) {													\
+			s[i] = 0;													\
+			if (n == max) {												\
+				max = max? max<<1 : 2;									\
+				offsets = (int*)realloc(offsets, sizeof(int) * max);	\
+			}															\
+			offsets[n++] = last_start;									\
+		} else ++n;														\
+	} while (0)
+
+	for (i = 0, last_char = last_start = 0; i <= l; ++i) {
+		if (delimiter == 0) {
+			if (isspace(s[i]) || s[i] == 0) {
+				if (isgraph(last_char)) __ksplit_aux; // the end of a field
+			} else {
+				if (isspace(last_char) || last_char == 0) last_start = i;
+			}
+		} else {
+			if (s[i] == delimiter || s[i] == 0) {
+				if (last_char != 0 && last_char != delimiter) __ksplit_aux; // the end of a field
+			} else {
+				if (last_char == delimiter || last_char == 0) last_start = i;
+			}
+		}
+		last_char = s[i];
+	}
+	*_max = max; *_offsets = offsets;
+	return n;
+}
+
+/**********************
+ * Boyer-Moore search *
+ **********************/
+
+// reference: http://www-igm.univ-mlv.fr/~lecroq/string/node14.html
+int *ksBM_prep(const uint8_t *pat, int m)
+{
+	int i, *suff, *prep, *bmGs, *bmBc;
+	prep = calloc(m + 256, 1);
+	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;
+}
+
+int *ksBM_search(const uint8_t *str, int n, const uint8_t *pat, int m, int *_prep, int *n_matches)
+{
+	int i, j, *prep, *bmGs, *bmBc;
+	int *matches = 0, mm = 0, nm = 0;
+	prep = _prep? _prep : ksBM_prep(pat, m);
+	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) {
+			if (nm == mm) {
+				mm = mm? mm<<1 : 1;
+				matches = realloc(matches, mm * sizeof(int));
+			}
+			matches[nm++] = j;
+			j += bmGs[0];
+		} else {
+			int max = bmBc[str[i+j]] - m + 1 + i;
+			if (max < bmGs[i]) max = bmGs[i];
+			j += max;
+		}
+	}
+	*n_matches = nm;
+	if (_prep == 0) free(prep);
+	return matches;
+}
+
+#ifdef KSTRING_MAIN
+#include <stdio.h>
+int main()
+{
+	kstring_t *s;
+	int *fields, n, i;
+	s = (kstring_t*)calloc(1, sizeof(kstring_t));
+	// test ksprintf()
+	ksprintf(s, " abcdefg:    %d ", 100);
+	printf("'%s'\n", s->s);
+	// test ksplit()
+	fields = ksplit(s, 0, &n);
+	for (i = 0; i < n; ++i)
+		printf("field[%d] = '%s'\n", i, s->s + fields[i]);
+	free(s);
+
+	{
+		static char *str = "abcdefgcdg";
+		static char *pat = "cd";
+		int n, *matches;
+		matches = ksBM_search(str, strlen(str), pat, strlen(pat), 0, &n);
+		printf("%d: \n", n);
+		for (i = 0; i < n; ++i)
+			printf("- %d\n", matches[i]);
+		free(matches);
+	}
+	return 0;
+}
+#endif