pd.if.org Git - liblfds/blob - liblfds/liblfds6.1.0/liblfds610/src/lfds610_stack/lfds610_stack_push_pop.c

   1 #include "lfds610_stack_internal.h"
   2
   3
   4
   5
   6
   7 /****************************************************************************/
   8 int lfds610_stack_push( struct lfds610_stack_state *ss, void *user_data )
   9 {
  10   LFDS610_ALIGN(LFDS610_ALIGN_DOUBLE_POINTER) struct lfds610_stack_element
  11     *se[LFDS610_STACK_PAC_SIZE];
  12
  13   assert( ss != NULL );
  14   // TRD : user_data can be NULL
  15
  16   lfds610_stack_internal_new_element_from_freelist( ss, se, user_data );
  17
  18   if( se[LFDS610_STACK_POINTER] == NULL )
  19     return( 0 );
  20
  21   lfds610_stack_internal_push( ss, se );
  22
  23   return( 1 );
  24 }
  25
  26
  27
  28
  29
  30 /****************************************************************************/
  31 int lfds610_stack_guaranteed_push( struct lfds610_stack_state *ss, void *user_data )
  32 {
  33   LFDS610_ALIGN(LFDS610_ALIGN_DOUBLE_POINTER) struct lfds610_stack_element
  34     *se[LFDS610_STACK_PAC_SIZE];
  35
  36   assert( ss != NULL );
  37   // TRD : user_data can be NULL
  38
  39   /* TRD : this function allocated a new lfds610_freelist element and uses that
  40            to push onto the lfds610_stack, guaranteeing success (unless malloc()
  41            fails of course)
  42   */
  43
  44   lfds610_stack_internal_new_element( ss, se, user_data );
  45
  46   // TRD : malloc failed
  47   if( se[LFDS610_STACK_POINTER] == NULL )
  48     return( 0 );
  49
  50   lfds610_stack_internal_push( ss, se );
  51
  52   return( 1 );
  53 }
  54
  55
  56
  57
  58
  59 /****************************************************************************/
  60 void lfds610_stack_internal_push( struct lfds610_stack_state *ss, struct lfds610_stack_element *se[LFDS610_STACK_PAC_SIZE] )
  61 {
  62   LFDS610_ALIGN(LFDS610_ALIGN_DOUBLE_POINTER) struct lfds610_stack_element
  63     *original_se_next[LFDS610_STACK_PAC_SIZE];
  64
  65   assert( ss != NULL );
  66   assert( se != NULL );
  67
  68   LFDS610_BARRIER_LOAD;
  69
  70   original_se_next[LFDS610_STACK_POINTER] = ss->top[LFDS610_STACK_POINTER];
  71   original_se_next[LFDS610_STACK_COUNTER] = ss->top[LFDS610_STACK_COUNTER];
  72
  73   do
  74   {
  75     se[LFDS610_STACK_POINTER]->next[LFDS610_STACK_POINTER] = original_se_next[LFDS610_STACK_POINTER];
  76     se[LFDS610_STACK_POINTER]->next[LFDS610_STACK_COUNTER] = original_se_next[LFDS610_STACK_COUNTER];
  77   }
  78   while( 0 == lfds610_abstraction_dcas((volatile lfds610_atom_t *) ss->top, (lfds610_atom_t *) se, (lfds610_atom_t *) original_se_next) );
  79
  80   return;
  81 }
  82
  83
  84
  85
  86
  87 /****************************************************************************/
  88 int lfds610_stack_pop( struct lfds610_stack_state *ss, void **user_data )
  89 {
  90   LFDS610_ALIGN(LFDS610_ALIGN_DOUBLE_POINTER) struct lfds610_stack_element
  91     *se[LFDS610_STACK_PAC_SIZE];
  92
  93   assert( ss != NULL );
  94   assert( user_data != NULL );
  95
  96   LFDS610_BARRIER_LOAD;
  97
  98   se[LFDS610_STACK_COUNTER] = ss->top[LFDS610_STACK_COUNTER];
  99   se[LFDS610_STACK_POINTER] = ss->top[LFDS610_STACK_POINTER];
 100
 101   do
 102   {
 103     if( se[LFDS610_STACK_POINTER] == NULL )
 104       return( 0 );
 105   }
 106   while( 0 == lfds610_abstraction_dcas((volatile lfds610_atom_t *) ss->top, (lfds610_atom_t *) se[LFDS610_STACK_POINTER]->next, (lfds610_atom_t *) se) );
 107
 108   *user_data = se[LFDS610_STACK_POINTER]->user_data;
 109
 110   lfds610_freelist_push( ss->fs, se[LFDS610_STACK_POINTER]->fe );
 111
 112   return( 1 );
 113 }
 114