More quality of life changes

1 files changed, 59 insertions, 0 deletions

diff --git a/src/str.c b/src/str.c
new file mode 100644
index 0000000..9cf5685
--- /dev/null
+++ b/src/str.c
@@ -0,0 +1,59 @@
+#include "db.h"
+
+
+uint16_t len(const char *s){
+	uint16_t l = -1;
+	while(s[++l]);
+	return l;
+}
+
+bool sameStr(const char *s1, const char *s2){
+	uint16_t i1 = 0, i2 = 0;
+	while(s1[i1] && s2[i2] && s1[i1] == s2[i2])
+		++i1, ++i2;
+	return !s1[i1] && !s2[i2];
+}
+
+// Auxiliary function for creating a lookup table of the haystack
+// table[i] will be the number of shifts right until the next
+// separator when checking position i
+// Only really useful for this implementation of tags
+static int *table(const char *y, int n, char sep){
+	int *tb = calloc(n, sizeof(int));
+	if(tb == NULL){
+		fprintf(stderr, "Error callocating array (table)");
+		exit(EXIT_FAILURE);
+	}
+
+	int lSep = n-1;
+	for(int i = n-1; i >= 0; --i){
+		if(y[i] == sep){
+			tb[i] = 1;
+			lSep = i;
+		}else if(y[i] != '\0'){
+			tb[i] = lSep-i;
+		}
+	}
+	return tb;
+}
+
+// Returns the position of ndl in tags, -1 if its not found
+// A return of 0 means ndl occurs in tags starting in position 0
+// Use 'if(strInTags(...) != -1)' when using this function
+ssize_t strInTags(const char *tags, int n, const char *ndl, int m, char sep){
+	int *tb = table(tags, n, sep);
+
+	for(int i = 0; i < n; ){
+		int j = 0;
+		while(j < m && tags[i+j] == ndl[j]){
+			++j;
+		}
+		if(j == m){
+			return i;
+		}
+		if(tags[i+j] != ndl[j]){
+			i += tb[i];
+		}
+	}
+	return -1;
+}
\ No newline at end of file