md5: Allocate a normal private context for the opaque md5 context pointer

This avoids having to overestimate the md5 context size, which
isn't known beforehand, allowing us to use the new allocate functions
instead.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 15 insertions, 9 deletions

diff --git a/libavformat/md5proto.c b/libavformat/md5proto.c
index 796b4ea..12ddde3 100644
--- a/libavformat/md5proto.c
+++ b/libavformat/md5proto.c
@@ -27,37 +27,41 @@
 #include "avio.h"
 #include "url.h"
 
-#define PRIV_SIZE 128
+struct MD5Context {
+    struct AVMD5 *md5;
+};
 
 static int md5_open(URLContext *h, const char *filename, int flags)
 {
-    if (PRIV_SIZE < av_md5_size) {
-        av_log(NULL, AV_LOG_ERROR, "Insuffient size for MD5 context\n");
-        return -1;
-    }
+    struct MD5Context *c = h->priv_data;
 
     if (!(flags & AVIO_FLAG_WRITE))
         return AVERROR(EINVAL);
 
-    av_md5_init(h->priv_data);
+    c->md5 = av_md5_alloc();
+    if (!c->md5)
+        return AVERROR(ENOMEM);
+    av_md5_init(c->md5);
 
     return 0;
 }
 
 static int md5_write(URLContext *h, const unsigned char *buf, int size)
 {
-    av_md5_update(h->priv_data, buf, size);
+    struct MD5Context *c = h->priv_data;
+    av_md5_update(c->md5, buf, size);
     return size;
 }
 
 static int md5_close(URLContext *h)
 {
+    struct MD5Context *c = h->priv_data;
     const char *filename = h->filename;
     uint8_t md5[16], buf[64];
     URLContext *out;
     int i, err = 0;
 
-    av_md5_final(h->priv_data, md5);
+    av_md5_final(c->md5, md5);
     for (i = 0; i < sizeof(md5); i++)
         snprintf(buf + i*2, 3, "%02x", md5[i]);
     buf[i*2] = '\n';
@@ -76,6 +80,8 @@ static int md5_close(URLContext *h)
             err = AVERROR(errno);
     }
 
+    av_freep(&c->md5);
+
     return err;
 }
 
@@ -85,5 +91,5 @@ URLProtocol ff_md5_protocol = {
     .url_open            = md5_open,
     .url_write           = md5_write,
     .url_close           = md5_close,
-    .priv_data_size      = PRIV_SIZE,
+    .priv_data_size      = sizeof(struct MD5Context),
 };