1 #include "lfds611_stack_internal.h"
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7 /****************************************************************************/
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8 void lfds611_stack_query( struct lfds611_stack_state *ss, enum lfds611_stack_query_type query_type, void *query_input, void *query_output )
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10 assert( ss != NULL );
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11 // TRD : query_type can be any value in its range
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12 // TRD : query_iput can be NULL
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13 assert( query_output != NULL );
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15 LFDS611_BARRIER_LOAD;
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17 switch( query_type )
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19 case LFDS611_STACK_QUERY_ELEMENT_COUNT:
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20 assert( query_input == NULL );
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22 lfds611_freelist_query( ss->fs, LFDS611_FREELIST_QUERY_ELEMENT_COUNT, NULL, query_output );
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25 case LFDS611_STACK_QUERY_VALIDATE:
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26 // TRD : query_input can be NULL
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28 /* TRD : the validation info passed in is for the stack
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29 it indicates the minimum and maximum number of elements
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30 which should be present
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32 we need to validate the freelist
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33 and validate the stack
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35 we cannot know the min/max for the freelist, given only
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36 the min/max for the stack
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39 lfds611_freelist_query( ss->fs, LFDS611_FREELIST_QUERY_VALIDATE, NULL, (enum lfds611_data_structure_validity *) query_output );
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41 if( *(enum lfds611_data_structure_validity *) query_output == LFDS611_VALIDITY_VALID )
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42 lfds611_stack_internal_validate( ss, (struct lfds611_validation_info *) query_input, (enum lfds611_data_structure_validity *) query_output, ((enum lfds611_data_structure_validity *) query_output)+1 );
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53 /****************************************************************************/
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54 void lfds611_stack_internal_validate( struct lfds611_stack_state *ss, struct lfds611_validation_info *vi, enum lfds611_data_structure_validity *stack_validity, enum lfds611_data_structure_validity *freelist_validity )
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56 struct lfds611_stack_element
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65 struct lfds611_validation_info
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68 assert( ss != NULL );
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69 // TRD : vi can be NULL
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70 assert( stack_validity != NULL );
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72 *stack_validity = LFDS611_VALIDITY_VALID;
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74 se_slow = se_fast = (struct lfds611_stack_element *) ss->top[LFDS611_STACK_POINTER];
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76 /* TRD : first, check for a loop
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77 we have two pointers
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78 both of which start at the top of the stack
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80 and on each iteration
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81 we advance one pointer by one element
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82 and the other by two
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84 we exit the loop when both pointers are NULL
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85 (have reached the end of the stack)
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89 if we fast pointer 'sees' the slow pointer
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90 which means we have a loop
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93 if( se_slow != NULL )
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96 se_slow = se_slow->next[LFDS611_STACK_POINTER];
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98 if( se_fast != NULL )
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99 se_fast = se_fast->next[LFDS611_STACK_POINTER];
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101 if( se_fast != NULL )
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102 se_fast = se_fast->next[LFDS611_STACK_POINTER];
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104 while( se_slow != NULL and se_fast != se_slow );
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106 if( se_fast != NULL and se_slow != NULL and se_fast == se_slow )
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107 *stack_validity = LFDS611_VALIDITY_INVALID_LOOP;
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109 /* TRD : now check for expected number of elements
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110 vi can be NULL, in which case we do not check
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111 we know we don't have a loop from our earlier check
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114 if( *stack_validity == LFDS611_VALIDITY_VALID and vi != NULL )
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116 se = (struct lfds611_stack_element *) ss->top[LFDS611_STACK_POINTER];
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118 while( se != NULL )
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121 se = (struct lfds611_stack_element *) se->next[LFDS611_STACK_POINTER];
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124 if( element_count < vi->min_elements )
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125 *stack_validity = LFDS611_VALIDITY_INVALID_MISSING_ELEMENTS;
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127 if( element_count > vi->max_elements )
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128 *stack_validity = LFDS611_VALIDITY_INVALID_ADDITIONAL_ELEMENTS;
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131 /* TRD : now we validate the freelist
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133 we may be able to check for the expected number of
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134 elements in the freelist
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136 if the caller has given us an expected min and max
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137 number of elements in the stack, then the total number
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138 of elements in the freelist, minus that min and max,
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139 gives us the expected number of elements in the
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145 lfds611_freelist_query( ss->fs, LFDS611_FREELIST_QUERY_ELEMENT_COUNT, NULL, (void *) &total_elements );
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147 freelist_vi.min_elements = total_elements - vi->max_elements;
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148 freelist_vi.max_elements = total_elements - vi->min_elements;
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150 lfds611_freelist_query( ss->fs, LFDS611_FREELIST_QUERY_VALIDATE, (void *) &freelist_vi, (void *) freelist_validity );
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154 lfds611_freelist_query( ss->fs, LFDS611_FREELIST_QUERY_VALIDATE, NULL, (void *) freelist_validity );
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