From 067b8f578c7b189840383b979ea4ca8ccc88ebe9 Mon Sep 17 00:00:00 2001
From: Matthias Kramm <kramm@quiss.org>
Date: Sun, 8 Feb 2009 21:20:14 +0100
Subject: [PATCH] added trie data structure

---
 lib/q.c |   34 ++++++++++++++++++++++++++++++++++
 lib/q.h |    9 +++++++++
 2 files changed, 43 insertions(+)

diff --git a/lib/q.c b/lib/q.c
index 9438033..e578107 100644
--- a/lib/q.c
+++ b/lib/q.c
@@ -278,6 +278,40 @@ void** heap_flatten(heap_t*h)
     return nodes;
 }
 
+// ------------------------------- trie --------------------------------------
+
+void trie_put(trie_t**t, unsigned const char*id)
+{
+    if(!*t) {
+        (*t) = rfx_calloc(sizeof(trie_t));
+        (*t)->rest = (unsigned char*)strdup(id);
+        return;
+    } 
+    if((*t)->rest && (*t)->rest[0]) {
+        // shift whatever's currently in here one node down
+        trie_put(&(*t)->row[(*t)->rest[0]], (*t)->rest+1);
+        (*t)->rest = 0;
+    }
+    if(id[0]) {
+        trie_put(&(*t)->row[id[0]], id+1);
+    } else {
+        (*t)->rest = "";
+    }
+}
+
+int trie_lookup(trie_t*t, unsigned const char*id)
+{
+    while(t) {
+        if(t->rest && !strcmp(t->rest, id))
+            return 1;
+        t = t->row[id[0]];
+        if(!*id) 
+            return 0;
+        id++;
+    }
+    return 0;
+}
+
 // ------------------------------- crc32 --------------------------------------
 static unsigned int*crc32 = 0;
 static void crc32_init(void)
diff --git a/lib/q.h b/lib/q.h
index 942bf28..3834e11 100644
--- a/lib/q.h
+++ b/lib/q.h
@@ -120,6 +120,12 @@ typedef struct _heap
     int(*compare)(const void *, const void *);
 } heap_t;
 
+typedef struct _trie {
+    struct _trie*row[256];
+    unsigned char*rest;
+} trie_t;
+
+
 char* strdup_n(const char*str, int size);
 
 unsigned int crc32_add_byte(unsigned int crc32, unsigned char b);
@@ -201,6 +207,9 @@ void* heap_chopmax(heap_t*h);
 void heap_dump(heap_t*h, FILE*fi);
 void** heap_flatten(heap_t*h);
 
+void trie_put(trie_t**t, unsigned const char*id);
+int trie_lookup(trie_t*t, unsigned const char*id);
+
 array_t* array_new();
 array_t* array_new2(type_t*type);
 void array_free(array_t*array);
-- 
1.7.10.4