Revert recent changes that are broken

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15439 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 11 insertions, 9 deletions

diff --git a/apps/buffering.c b/apps/buffering.c
index 96c9d61..b92b5d1 100644
--- a/apps/buffering.c
+++ b/apps/buffering.c
@@ -105,7 +105,7 @@
 
 /* assert(sizeof(struct memory_handle)%4==0) */
 struct memory_handle {
-    int id;                    /* A unique ID for the handle */
+    unsigned int id;           /* A unique ID for the handle */
     enum data_type type;       /* Type of data buffered with this handle */
     char path[MAX_PATH];       /* Path if data originated in a file */
     int fd;                    /* File descriptor to path (-1 if closed) */
@@ -146,7 +146,7 @@ static struct memory_handle *first_handle;
 
 static int num_handles;  /* number of handles in the list */
 
-static int base_handle_id;
+static unsigned int base_handle_id;
 
 static struct mutex llist_mutex;
 
@@ -224,7 +224,7 @@ static struct memory_handle *add_handle(size_t data_size, const bool can_wrap,
                                         const bool alloc_all)
 {
     /* gives each handle a unique id, unsigned to handle wraps gracefully */
-    static int cur_handle_id = 0;
+    static unsigned int cur_handle_id = 1;
     size_t shift;
     size_t new_widx;
     size_t len;
@@ -291,7 +291,9 @@ static struct memory_handle *add_handle(size_t data_size, const bool can_wrap,
     buf_widx = RINGBUF_ADD(buf_widx, sizeof(struct memory_handle));
 
     new_handle->id = cur_handle_id;
-    cur_handle_id = (cur_handle_id + 1) & BUF_HANDLE_ID_MASK;
+    /* Use += 2 instead of ++ to guarantee that the low bit is always high and
+     * prevent the assignment of a zero id when wrapping. */
+    cur_handle_id += 2;
     new_handle->next = NULL;
     num_handles++;
 
@@ -356,9 +358,9 @@ static bool rm_handle(const struct memory_handle *h)
 
 /* Return a pointer to the memory handle of given ID.
    NULL if the handle wasn't found */
-static struct memory_handle *find_handle(const int handle_id)
+static struct memory_handle *find_handle(const unsigned int handle_id)
 {
-    if (handle_id < 0)
+    if (handle_id <= 0)
         return NULL;
 
     mutex_lock(&llist_mutex);
@@ -548,7 +550,7 @@ static bool buffer_handle(int handle_id)
     logf("buffer_handle(%d)", handle_id);
     struct memory_handle *h = find_handle(handle_id);
     if (!h)
-        return false;
+        return -1;
 
     if (h->filerem == 0) {
         /* nothing left to buffer */
@@ -768,7 +770,7 @@ void update_data_counters(void)
 {
     struct memory_handle *m = find_handle(base_handle_id);
     if (!m)
-        base_handle_id = -1;
+        base_handle_id = 0;
 
     memset(&data_counters, 0, sizeof(data_counters));
 
@@ -1308,7 +1310,7 @@ bool buffering_reset(char *buf, size_t buflen)
     cur_handle = NULL;
     cached_handle = NULL;
     num_handles = 0;
-    base_handle_id = -1;
+    base_handle_id = 0;
 
     buffer_callback_count = 0;
     memset(buffer_low_callback_funcs, 0, sizeof(buffer_low_callback_funcs));