transliteration: use double pointers on syllable chain

syllable.c

@@ -3,17 +3,18 @@
 #include <stdlib.h>
 #include <string.h>
 #include "syllable.h"
+#include "utf8.h"
 
 
-struct syllable *syllable_alloc(const char *data)
+struct syllable *syllable_alloc(const char *data, unsigned int code)
 {
 	struct syllable *ptr = malloc(sizeof(*ptr));
 
 	if (ptr == NULL)
 		goto out;
 
-	ptr->data = strdup(data);
+	ptr->data = data != NULL ? strdup(data) : utf8_code_to_string(code);
-	ptr->code = 0;
+	ptr->code = code;
 	ptr->prev = NULL;
 	ptr->next = NULL;
 
@@ -30,17 +31,6 @@ void syllable_drop(struct syllable *ptr)
 	free(ptr);
 }
 
-struct syllable *syllable_append(struct syllable *tail, const char *data)
-{
-	struct syllable *ptr;
-
-	ptr = syllable_alloc(data);
-	ptr->prev = tail;
-	tail->next = ptr;
-
-	return ptr;
-}
-
 unsigned int syllable_chain_length(struct syllable *head)
 {
 	struct syllable *walk = head;

syllable.h

@@ -10,11 +10,9 @@ struct syllable {
 	struct syllable *next;
 };
 
-struct syllable *syllable_alloc();
+struct syllable *syllable_alloc(const char *data, unsigned int code);
 void syllable_drop(struct syllable *syllable);
 
-struct syllable *syllable_append(struct syllable *tail, const char *data);
-
 unsigned int syllable_chain_length(struct syllable *head);
 char *syllable_chain_to_string(struct syllable *head);
 void syllable_chain_drop(struct syllable *head);

transliteration.c

@@ -28,6 +28,9 @@ static void syllable_modify(struct syllable *syllable, const char *data)
 {
 	char buffer[10];
 
+	if (syllable == NULL)
+		return;
+
 	strcpy(buffer, syllable->data);
 	buffer[strlen(buffer) - 1] = 0;
 	strcat(buffer, data);
@@ -47,46 +50,35 @@ static void apply_transliteration_filters(struct syllable *head,
 	}
 }
 
-char *transliterate_devanagari_to_latin(const char *text,
+char *transliterate_devanagari_to_latin(const char *devanagari,
 	const struct transliteration_context *context)
 {
-	unsigned int length = strlen(text);
+	struct syllable *head = NULL, *tail = NULL, **indirect = &head;
-	const char *ptr = text;
-	const char *end = ptr + length;
-	char *tmp;
-	unsigned int code;
-	struct syllable *head, *tail;
 	const struct transliteration_letter *letter;
-
+	const char *ptr = devanagari;
-	head = syllable_alloc("");
+	const char *end = ptr + strlen(devanagari);
-	tail = head;
+	unsigned int code;
+	char *retval;
 
 	while (ptr < end) {
 		code = utf8_unpack_char(ptr);
 		ptr += utf8_char_length(code);
 
 		letter = find_letter_by_code(code, context->table);
-		if (letter != NULL) {
+		if (letter && letter->flags & FLAG_MODIFIER) {
-
-			if (letter->flags & FLAG_REGULAR) {
-				tail = syllable_append(tail, letter->data);
-				tail->code = code;
-			} else if (letter->flags & FLAG_MODIFIER) {
 			syllable_modify(tail, letter->data);
-			}
-
 			continue;
 		}
 
-		tmp = utf8_code_to_string(code);
+		*indirect = syllable_alloc(letter ? letter->data : NULL, code);
-		tail = syllable_append(tail, tmp);
+		tail = *indirect;
-		free(tmp);
+		indirect = &(*indirect)->next;
 	}
 
 	apply_transliteration_filters(head, context->filters);
 
-	tmp = syllable_chain_to_string(head);
+	retval = syllable_chain_to_string(head);
 	syllable_chain_drop(head);
 
-	return tmp;
+	return retval;
 }