[PATCH v2 8/9] winedmo: Use the stream context as a buffer for larger reads.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/winedmo/main.c    |  3 ++-
 dlls/winedmo/unixlib.c | 26 ++++++++++++++++++--------
 dlls/winedmo/unixlib.h |  4 ++++
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/dlls/winedmo/main.c b/dlls/winedmo/main.c
index 5bd66733d86..9de56e64902 100644
--- a/dlls/winedmo/main.c
+++ b/dlls/winedmo/main.c
@@ -27,9 +27,10 @@ static struct stream_context *stream_context_create(void)
 {
     struct stream_context *context;

-    if (!(context = malloc( sizeof(*context) ))) return NULL;
+    if (!(context = malloc( 0x10000 ))) return NULL;
     context->length = 0;
     context->position = 0;
+    context->buffer_size = 0x10000 - offsetof(struct stream_context, buffer);

return context;
 }
diff --git a/dlls/winedmo/unixlib.c b/dlls/winedmo/unixlib.c
index 33c8bea54aa..59c83554c0d 100644
--- a/dlls/winedmo/unixlib.c
+++ b/dlls/winedmo/unixlib.c
@@ -57,18 +57,28 @@ int64_t unix_seek_callback( void *opaque, int64_t offset, int whence )

int unix_read_callback( void *opaque, uint8_t *buffer, int size )
 {
-    struct read_callback_params params = {.dispatch = {.callback = read_callback}, .context = (UINT_PTR)opaque};
     struct stream_context *context = opaque;
-    int status, total;
-    void *ret_ptr;
-    ULONG ret_len;
+    int ret, status, total = 0;

TRACE( "opaque %p, buffer %p, size %#x\n", opaque, buffer, size );

-    params.size = size;
-    status = KeUserDispatchCallback( &params.dispatch, sizeof(params), &ret_ptr, &ret_len );
-    if (status || ret_len != sizeof(ULONG)) return AVERROR( EINVAL );
-    total = *(ULONG *)ret_ptr;
+    if (!size) return AVERROR_EOF;
+
+    do
+    {
+        struct read_callback_params params = {.dispatch = {.callback = read_callback}, .context = (UINT_PTR)context};
+        void *ret_ptr;
+        ULONG ret_len;
+
+        params.size = min( size, context->buffer_size );
+        status = KeUserDispatchCallback( &params.dispatch, sizeof(params), &ret_ptr, &ret_len );
+        if (status || ret_len != sizeof(ULONG)) return AVERROR( EINVAL );
+        if (!(ret = *(ULONG *)ret_ptr)) break;
+        memcpy( buffer, context->buffer, ret );
+        buffer += ret;
+        total += ret;
+        size -= ret;
+    } while (size && ret == context->buffer_size);

if (!total) return AVERROR_EOF;
     context->position += total;
diff --git a/dlls/winedmo/unixlib.h b/dlls/winedmo/unixlib.h
index e97e47ea259..5aa4cc42ba2 100644
--- a/dlls/winedmo/unixlib.h
+++ b/dlls/winedmo/unixlib.h
@@ -41,8 +41,12 @@ struct stream_context
 {
     UINT64 length;
     UINT64 position;
+    UINT64 buffer_size;
+    BYTE buffer[];
 };

+C_ASSERT( sizeof(struct stream_context) == offsetof( struct stream_context, buffer[0] ) );
+
 struct seek_callback_params
 {
     struct dispatch_callback_params dispatch;