Initial commit

1 files changed, 122 insertions, 0 deletions

diff --git a/storage.c b/storage.c
new file mode 100644
index 0000000..043eeae
--- /dev/null
+++ b/storage.c
@@ -0,0 +1,122 @@
+#include "db.h"
+
+
+
+
+// Splits src into words based on a separator character (sep) and stores them in arr, and the length in len. Inspired by https://github.com/joshdk/tag/blob/master/src/dsv.c's split
+void split(const char *src, char sep, char ***arr, int *len){
+	int i = 0, asize = 1, ai = 0, wsize = 1, wi = 0;
+	char c = 0;
+
+	(*arr) = malloc(asize*sizeof(char*));
+	(*arr)[ai] = malloc(wsize*sizeof(char));
+
+	while((c = src[i]) != '\0'){
+		// If there's a new word (new array index) reallocate the array and allocate space for it
+		if(wi == 0){
+			char **tmp;
+			if((tmp = realloc((*arr), (asize+ai)*sizeof(char*))) != NULL){
+				*arr = tmp;
+				tmp = NULL;
+			}else{
+				fprintf(stderr, "Error reallocating array (split)");
+				exit(EXIT_FAILURE);
+			}
+			(*arr)[ai] = malloc(wsize*sizeof(char));
+		}
+		// Allocate space for a new character in a word
+		char *tmp;
+		if((tmp = realloc((*arr)[ai], (wsize+wi)*sizeof(char))) != NULL){
+			strcpy(tmp, (*arr)[ai]);
+			(*arr)[ai] = tmp;
+			tmp = NULL;
+		}else{
+			fprintf(stderr, "Error reallocating word (split)");
+			exit(EXIT_FAILURE);
+		}
+		// If the character is a separator, terminate the string and increment the array index; if not, assign the character and increment the word index
+		if(c == sep){
+			(*arr)[ai][wi] = '\0';
+			wi = 0;
+			++ai;
+		}else{
+			(*arr)[ai][wi] = c;
+			++wi;
+		}
+		++i;
+	}
+	if(src[i-1] != sep){
+		(*arr)[ai][wi] = '\0';
+		++ai;
+	}
+	(*arr)[ai] = NULL;
+	*len = ai;
+}
+
+void swapWords(char ***arr, int a, int b){
+	char *tmp = (*arr)[a];
+	(*arr)[a] = (*arr)[b];
+	(*arr)[b] = tmp;
+}
+
+char *normalizeTag(char *tag){
+	uint16_t l = len(tag);
+	char *ntag = calloc(l+1, sizeof(char));
+	for(int i = 0; i < l; ++i){
+		ntag[i] = tolower(tag[i]);
+	}
+	return ntag;
+}
+
+// Adds a tag in the tags array in the row r, sorted by natural string comparison with strnatcmp
+// We assume that when adding a tag all other tags are already sorted
+void insertTag(row *r, char *tag){
+
+	tag = normalizeTag(tag);
+
+	// Dump tags into array of strings and add tag
+	char **arr, **tmp;
+	int l;
+	split(r->tags, ';', &arr, &l);
+	if((tmp = realloc(arr, (l+1)*sizeof(char*))) != NULL){
+		arr = tmp;
+		tmp = NULL;
+	}else{
+		fprintf(stderr, "Error reallocating array (insertTag)");
+		exit(EXIT_FAILURE);
+	}
+	arr[l] = malloc((len(tag)+1)*sizeof(char));
+	strcpy(arr[l], tag);
+	
+	// Sort tag by natural string comparison, starting from the last element (the new tag)
+	for(int i = l; i > 0; --i){
+		switch(strnatcmp(arr[i-1], arr[i])){
+			case 1:
+				// arr[i-1] is higher than arr[i]; swap them
+				swapWords(&arr, i, i-1);
+				break;
+			case -1:
+				// arr[i-1] is lower than arr[i]; exit loop
+				i = 0;
+				break;
+			case 0:
+				// The tag already exists, no need to alter anything
+				free(arr);
+				return;
+		}
+	}
+	++l; // Succesfully added new tag
+
+	// Insert tags back into tags member of row structure with the ';' separator in between them
+	int g = 0;
+	for(int i = 0; i < l; ++i){
+		int j = 0;
+		while(arr[i][j] != '\0'){
+			r->tags[g] = arr[i][j];
+			++j;
+			++g;
+		}
+		r->tags[g++] = ';';
+	}
+	r->tags[g] = '\0';
+}
\ No newline at end of file