Zero count of consumers/tail readers of CBUFF is handled now.

[ulut.git] / ulut / ul_cbuff.h

diff --git a/ulut/ul_cbuff.h b/ulut/ul_cbuff.h
index bc54c0c05cfc5e020cfee93dcb21bb5600781618..a6fd8d8c06cc64a80d196cb6828bdbc58e1e803a 100644 (file)
--- a/ulut/ul_cbuff.h
+++ b/ulut/ul_cbuff.h
@@ -108,6 +108,7 @@ int ul_cbuff_tail_test(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info);
 int ul_cbuff_tail_release(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info);
 int ul_cbuff_tail_next(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info);
 int ul_cbuff_tail_state_update(ul_cbuff_t *buff, int release_result, ul_cbuff_loc_t loc, ul_cbuff_loc_t loc_next);
+int ul_cbuff_tail_detach_onestep(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info);
 void ul_cbuff_data_do_wrap(ul_cbuff_data_info_t *data_info);
 int ul_cbuff_data_at_once(ul_cbuff_data_info_t *data_info, void **pptr, int size);
 int ul_cbuff_put_data(ul_cbuff_data_info_t *data_info, const void *data, int size);
@@ -183,7 +184,14 @@ ul_cbuff_head_alloc(ul_cbuff_t *buff, ul_cbuff_put_info_t *put_info, unsigned in
 
   ((ul_cbuff_msg_head_t *)(buff->buff_start+state->head))->flags=0;
 
+  flags&=~(UL_CBUFF_MSG_READY|UL_CBUFF_MSG_READERS);
+
   put_info->msg_head->flags|=flags;
+  if(buff->state->readers>0)
+    put_info->msg_head->flags+=buff->state->readers;
+  else if (buff->state->readers==0)
+    put_info->msg_head->flags+=1;
+
   put_info->msg_head->length=length;
 
   return 0;
@@ -192,8 +200,6 @@ ul_cbuff_head_alloc(ul_cbuff_t *buff, ul_cbuff_put_info_t *put_info, unsigned in
 ul_cbuff_inline int
 ul_cbuff_head_put(ul_cbuff_t *buff, ul_cbuff_put_info_t *put_info)
 {
-  if(buff->state->readers>0)
-    put_info->msg_head->flags+=buff->state->readers;
   ul_cbuff_mark_ready(put_info->msg_head);
   put_info->msg_head=NULL;
   return 0;
@@ -258,21 +264,14 @@ ul_cbuff_tail_attach(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info, int mode
   ul_cbuff_state_t *state=buff->state;
   ul_cbuff_msg_head_t *msg_head;
 
-  msg_head=(ul_cbuff_msg_head_t *)(buff->buff_start+state->head);
+  if(state->readers>0)
+    msg_head=(ul_cbuff_msg_head_t *)(buff->buff_start+state->head);
+  else if(state->readers==0)
+    msg_head=(ul_cbuff_msg_head_t *)(buff->buff_start+state->lasttail);
   if(state->readers>=0)
     state->readers++;
-  if((state->readers<0)||(state->firsttail==state->head)){
-    tail_info->msg_head=msg_head;
-    tail_info->data.ptr=NULL;
-  }else{
-    /* There is already some message(s) write in progress */
-    tail_info->msg_head=NULL;
-    tail_info->msg_head->flags++;
-    /* Some data fields are abused for ready condition checking */
-    tail_info->data.ptr=(unsigned char*)msg_head;
-    tail_info->data.wrap_ptr=buff->buff_start+state->firsttail;
-    tail_info->data.wrap_len=state->cycles;
-  }
+  tail_info->msg_head=msg_head;
+  tail_info->data.ptr=NULL;
   return 0;
 }
 
@@ -280,23 +279,7 @@ ul_cbuff_inline int
 ul_cbuff_tail_incontact(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info)
 {
   if(tail_info->msg_head==NULL){
-    unsigned char *new_firsttail=buff->buff_start+buff->state->firsttail;
-    unsigned char *old_head=tail_info->data.ptr;
-    unsigned char *old_firsttail=tail_info->data.wrap_ptr;
-    unsigned int old_cycles=tail_info->data.wrap_len;
-    unsigned int new_cycles=buff->state->cycles;
-
-    if(old_firsttail<old_head){
-      if((new_firsttail<old_head)&&(new_cycles==old_cycles))
-        return 0;
-    }else{
-      if(new_cycles==old_cycles)
-        return 0;
-      if((new_firsttail<old_head)&&((new_cycles-old_cycles)==1))
-        return 0;
-    }
-    tail_info->msg_head=(ul_cbuff_msg_head_t *)old_head;
-    return 1;
+    return 0;
   }
   return 1;
 }
@@ -364,6 +347,39 @@ ul_cbuff_tail_state_update(ul_cbuff_t *buff, int release_result, ul_cbuff_loc_t
   }
 }
 
+ul_cbuff_inline int
+ul_cbuff_tail_detach_onestep(ul_cbuff_t *buff, ul_cbuff_tail_info_t *tail_info)
+{
+  ul_cbuff_state_t *state=buff->state;
+  ul_cbuff_loc_t loc;
+  ul_cbuff_loc_t loc_next;
+  unsigned msg_readers;
+
+  if(tail_info->msg_head==NULL)
+    return 0;
+
+  loc = ul_cbuff_head_loc(buff, tail_info->msg_head);
+
+  if(loc!=state->head) {
+    if(!ul_cbuff_is_ready(tail_info->msg_head))
+      return 2;
+    msg_readers=tail_info->msg_head->flags&UL_CBUFF_MSG_READERS;
+    loc_next=ul_cbuff_next_loc(buff, tail_info->msg_head);
+    if(msg_readers)
+      tail_info->msg_head->flags--;
+    tail_info->msg_head=(ul_cbuff_msg_head_t *)(buff->buff_start+loc_next);
+    ul_cbuff_tail_state_update(buff, msg_readers<=1? 1: 0, loc, loc_next);
+    return 1;
+  }
+
+  if(state->readers>0)
+    state->readers--;
+  tail_info->msg_head=NULL;
+  tail_info->data.ptr=NULL;
+  return 0;
+}
+
+
 ul_cbuff_inline void
 ul_cbuff_data_do_wrap(ul_cbuff_data_info_t *data_info)
 {