simplify some logic

diff --git a/src/stree.c b/src/stree.c
index 5b68bfedf61e2f01f3841f889998f8973e165f97..37ec431fe551c90236cd37df6e7adba5c856b8f8 100644 (file)
--- a/src/stree.c
+++ b/src/stree.c
@@ -65,30 +65,49 @@ static void node_split_son(struct node *self, struct node *edge, struct node *br
         self->son = split;
 }
 
+static void node_sort_sons(struct node *self)
+{
+    struct node *node, *brother, *tmp;
+
+    for (brother = (struct node *) 0, node = self->son; node && node->brother; brother = node, node = node->brother) {
+        if (node->to > node->brother->to) {
+            if (brother) {
+                tmp = node->brother;
+                node->brother = node->brother->brother;
+                tmp->brother = node;
+                brother->brother = tmp;
+            } else {
+                tmp = node->brother;
+                node->brother = node->brother->brother;
+                tmp->brother = node;
+                self->son = tmp;
+            }
+            brother = (struct node *) 0;
+            node = self->son;
+        }
+    }
+}
+
 static struct node *node_edge_inv(struct node *self, uint8_t edge, const uint8_t *str, struct node **brother, bool seen[], uint8_t *code, bool record_seen)
 {
     struct node *node;
 
     if (record_seen) {
-        for (node = self->son; node; node = node->brother) {
+        node_sort_sons(self);
+
+        for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother) {
             if (!seen[str[node->from]]) {
                 seen[str[node->from]] = true;
-                if (*code == 0) {
-                    edge = str[node->from];
-                    break;
-                }
+                if (*code == 0) return node;
                 --*code;
             }
         }
-        if (!node) {
-            return (struct node *) 0;
-        }
+    } else {
+        for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother)
+            if (str[node->from] == edge)
+                return node;
     }
 
-    for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother)
-        if (str[node->from] == edge)
-            return node;
-
     return (struct node *) 0;
 }
 
@@ -97,20 +116,21 @@ static struct node *node_edge(struct node *self, uint8_t edge, const uint8_t *st
     struct node *node;
 
     if (record_seen) {
-        for (node = self->son; node; node = node->brother) {
-            if (str[node->from] == edge)
-                break;
+        node_sort_sons(self);
+
+        for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother) {
+            if (str[node->from] == edge) return node;
             if (!seen[str[node->from]]) {
                 seen[str[node->from]] = true;
                 ++*code;
             }
         }
+    } else {
+        for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother)
+            if (str[node->from] == edge)
+                return node;
     }
 
-    for (*brother = (struct node *) 0, node = self->son; node; *brother = node, node = node->brother)
-        if (str[node->from] == edge)
-            return node;
-
     return (struct node *) 0;
 }
 
@@ -161,7 +181,6 @@ int stree_encode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
     struct node *active_node;
     struct node *active_edge = (struct node *) 0;
     struct node *brother = (struct node *) 0;
-    struct node *new_leaf;
     size_t active_len = 0;
     size_t rem = 0;
     size_t i;
@@ -193,7 +212,6 @@ int stree_encode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
                 if (!active_edge) {
                     node_init(nodes + n, i);
                     node_add_son(active_node, nodes + n);
-                    new_leaf = nodes + n;
                     ++n, --rem;
                 } else {
                     if (!seen[in[active_edge->from+active_len]]) {
@@ -205,13 +223,12 @@ int stree_encode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
                     if (prev) prev->link = nodes + n;
                     prev = nodes + n, n += 2, --rem;
                     if (active_node == root) --active_len;
-                    new_leaf = (struct node *) 0;
                 }
                 active_node = active_node->link ? active_node->link : (active_len = rem - 1, root);
-                if (active_len == 0 && active_node->son == new_leaf)
+                if (active_len == 0 && active_node->son == nodes + n - 1)
                     brother = active_edge = (struct node *) 0;
                 else
-                    active_edge = node_edge(active_node, in[i-active_len], in, &brother, seen, &code, active_len == 0 && active_node->son != new_leaf);
+                    active_edge = node_edge(active_node, in[i-active_len], in, &brother, seen, &code, active_len == 0);
             }
             while (active_edge && active_edge->from + active_len >= active_edge->to) {
                 active_node = active_edge;
@@ -250,7 +267,6 @@ int stree_decode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
     struct node *active_node;
     struct node *active_edge = (struct node *) 0;
     struct node *brother = (struct node *) 0;
-    struct node *new_leaf;
     size_t active_len = 0;
     size_t rem = 0;
     size_t i, n;
@@ -283,7 +299,6 @@ int stree_decode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
                 if (!active_edge) {
                     node_init(nodes + n, i);
                     node_add_son(active_node, nodes + n);
-                    new_leaf = nodes + n;
                     ++n, --rem;
                 } else {
                     if (!seen[out[active_edge->from+active_len]]) {
@@ -295,10 +310,9 @@ int stree_decode(size_t len, const uint8_t *in, uint8_t *out, size_t *aux)
                     if (prev) prev->link = nodes + n;
                     prev = nodes + n, n += 2, --rem;
                     if (active_node == root) --active_len;
-                    new_leaf = (struct node *) 0;
                 }
                 active_node = active_node->link ? active_node->link : (active_len = rem - 1, root);
-                if (active_len == 0 && active_node->son == new_leaf)
+                if (active_len == 0 && active_node->son == nodes + n - 1)
                     brother = active_edge = (struct node *) 0;
                 else
                     active_edge = node_edge_inv(active_node, out[i-active_len], out, &brother, seen, &code, active_len == 0);

diff --git a/test/test_stree.c b/test/test_stree.c
index 9047cd6b851742afe1cfc0409f79e49aa2272c01..acae1ca030b662ee930aa9ae0ac57998c2b2b481 100644 (file)
--- a/test/test_stree.c
+++ b/test/test_stree.c
@@ -58,7 +58,7 @@ static enum test_result test_stree_encode_so_example(void)
     ASSERT_EQ(2, out[3]);
     ASSERT_EQ(0, out[4]);
     ASSERT_EQ('x', out[5]);
-    ASSERT_EQ(3, out[6]);
+    ASSERT_EQ(1, out[6]);
     ASSERT_EQ(0, out[7]);
     ASSERT_EQ(0, out[8]);
     ASSERT_EQ('e', out[9]);