Libav Dictionary

gistfile1.txt

From 6919a147f72647de98791af7f0473643adc5854d Mon Sep 17 00:00:00 2001
From: Josh Allmann <joshua.allmann@gmail.com>
Date: Fri, 4 Jun 2010 22:58:00 -0700
Subject: [PATCH 1/2] Added dictionary data structure. This will make setting custom HTTP headers more flexible.

---
 libavformat/http.c |   91 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 91 insertions(+), 0 deletions(-)

diff --git a/libavformat/http.c b/libavformat/http.c
index 9be921b..199dc99 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -37,6 +37,19 @@
 #define URL_SIZE    4096
 #define MAX_REDIRECTS 8
 
+#define TABLESIZE 128
+
+typedef struct pair {
+    int hashval;
+    char key[128];
+    char value[128];
+    struct pair *next;
+} pair;
+
+typedef struct {
+    pair *table[TABLESIZE];
+} DictContext;
+
 typedef struct {
     URLContext *hd;
     unsigned char buffer[BUFFER_SIZE], *buf_ptr, *buf_end;
@@ -66,6 +79,84 @@ void ff_http_set_chunked_transfer_encoding(URLContext *h, int is_chunked)
     ((HTTPContext*)h->priv_data)->is_chunked = is_chunked;
 }
 
+/**
+ * bernstein hash function
+ * source:
+ *   http://groups.google.com/group/comp.lang.c/msg/6b82e964887d73d9?dmode=source&output=gplain
+ */
+static int hash(const char *key)
+{
+    int h = 5381;
+    while (*key) {
+        h = ((h << 5) + h) + *key++;
+    }
+    return h & (TABLESIZE-1);
+}
+
+static int dict_add(DictContext *hc, const char *key, const char *value)
+{
+    int hashval = hash(key);
+    pair *p = hc->table[hashval], *first = p;
+
+    while (p && strcmp(key, p->key))
+        p = p->next;
+
+    if (!p) {
+        pair* newp = (pair*)av_malloc(sizeof(pair));
+        if (!newp) return AVERROR(ENOMEM);
+        strncpy(newp->key, key, sizeof(newp->key));
+        newp->key[sizeof(newp->key)-1] = '\0';
+        newp->next = first;
+        p = hc->table[hashval] = newp;
+    }
+
+    strncpy(p->value, value, sizeof(p->value));
+    p->value[sizeof(p->value)-1] = '\0';
+    return 0;
+}
+
+static void dict_remove(DictContext *hc, const char *key)
+{
+    int hashval = hash(key);
+    pair *p = hc->table[hashval], *prev = NULL;
+    while (p && strcmp(key, p->key)) {
+        prev = p;
+        p = p->next;
+    }
+
+    if (p) {
+        if (prev)
+            prev->next = p->next;
+        else
+            hc->table[hashval] = p->next;
+        av_free(p);
+    }
+}
+
+static void free_buckets(pair *p)
+{
+    if (p->next)
+        free_buckets(p->next);
+    av_free(p);
+}
+
+static void dict_free(DictContext *hc)
+{
+    int i;
+    for (i = 0; i < TABLESIZE; i++) {
+        pair *p = hc->table[i];
+        if (p)
+            free_buckets(p);
+    }
+    av_free(hc);
+}
+
+static DictContext* dict_init(DictContext **hc)
+{
+    *hc = (DictContext*)av_mallocz(sizeof(DictContext*)*TABLESIZE);
+    return *hc;
+}
+
 /* return non zero if error */
 static int http_open_cnx(URLContext *h)
 {
-- 
1.7.0.4