Branch data     Line data    Source code

       1                 :             : #include "mem.h"
       2                 :             : #include "mem_internal.h"
       3                 :             : #include <string.h>
       4                 :             : 
       5                 :             : /**
       6                 :             :  * @brief Copy one descriptor into another when both descriptors use the same mode
       7                 :             :  *
       8                 :             :  * This helper copies one descriptor into another when both descriptors already
       9                 :             :  * use the same semantic mode.
      10                 :             :  * When both operands are treated as strings, the copy trusts the cached
      11                 :             :  * `source->string_length`, treats the source as a fixed-string payload that
      12                 :             :  * ends exactly at that cached visible length plus one terminator element, and
      13                 :             :  * delegates the replacement to @ref mem_copy_fixed_string. When both
      14                 :             :  * operands are already in data mode, the raw descriptor transfer is delegated
      15                 :             :  * to @ref mem_copy_data
      16                 :             :  *
      17                 :             :  * Mixed string/data copies are rejected on purpose. This helper does not perform
      18                 :             :  * implicit mode conversion because that would hide a change in the semantic kind
      19                 :             :  * of the payload behind a plain copy call. In string mode the source and
      20                 :             :  * destination must also use the same element size, and a string source must
      21                 :             :  * provide consistent cached string metadata
      22                 :             :  *
      23                 :             :  * @param destination Pointer to the destination descriptor that receives the copy
      24                 :             :  * @param source Pointer to the source descriptor to copy from
      25                 :             :  * @return `SUCCESS` on success; `FAILURE` otherwise
      26                 :             :  */
      27                 :         647 : Return mem_copy(
      28                 :             :         memory       *destination,
      29                 :             :         const memory *source)
      30                 :             : {
      31                 :             :         /* Status returned by this function through provide()
      32                 :             :            Default value assumes successful completion */
      33                 :         647 :         Return status = SUCCESS;
      34                 :             : 
      35                 :             :         /* Total source byte count passed to the routed copy helper */
      36                 :         647 :         size_t source_size_bytes = 0;
      37                 :             : 
      38                 :             :         /* Logical source element count used for fixed-string routing */
      39                 :         647 :         size_t source_total_elements = 0;
      40                 :             : 
      41   [ +  -  -  + ]:         647 :         if(destination == NULL || source == NULL)
      42                 :             :         {
      43                 :           0 :                 report("Memory management; copy arguments must be non-NULL");
      44                 :           0 :                 provide(FAILURE);
      45                 :             :         }
      46                 :             : 
      47   [ +  +  +  + ]:         647 :         if(destination->length > 0 && destination->data == NULL)
      48                 :             :         {
      49                 :           1 :                 report("Memory management; Descriptor has non-zero length with NULL data pointer");
      50                 :           1 :                 provide(FAILURE);
      51                 :             :         }
      52                 :             : 
      53   [ +  +  +  + ]:         646 :         if(source->length > 0 && source->data == NULL)
      54                 :             :         {
      55                 :           2 :                 report("Memory management; Descriptor has non-zero length with NULL data pointer");
      56                 :           2 :                 provide(FAILURE);
      57                 :             :         }
      58                 :             : 
      59         [ +  + ]:         644 :         if(destination->single_element_size == 0)
      60                 :             :         {
      61                 :           1 :                 report("Memory management; Destination element size is zero (uninitialized)");
      62                 :           1 :                 provide(FAILURE);
      63                 :             :         }
      64                 :             : 
      65         [ +  + ]:         643 :         if(source->single_element_size == 0)
      66                 :             :         {
      67                 :           1 :                 report("Memory management; Source element size is zero (uninitialized)");
      68                 :           1 :                 provide(FAILURE);
      69                 :             :         }
      70                 :             : 
      71         [ +  + ]:         642 :         if(destination->is_string != source->is_string)
      72                 :             :         {
      73                 :           2 :                 report("Memory management; Source and destination must both be strings or both be data");
      74                 :           2 :                 provide(FAILURE);
      75                 :             :         }
      76                 :             : 
      77         [ +  + ]:         640 :         if(destination->is_string == true)
      78                 :             :         {
      79         [ +  + ]:         635 :                 if(destination->single_element_size != source->single_element_size)
      80                 :             :                 {
      81                 :           1 :                         report("Memory management; Element size mismatch (%zu vs %zu)",
      82                 :             :                                 destination->single_element_size,
      83                 :             :                                 source->single_element_size);
      84                 :           1 :                         provide(FAILURE);
      85                 :             :                 }
      86                 :             : 
      87   [ +  +  -  + ]:         634 :                 if((source->length == 0 && source->string_length != 0) ||
      88   [ +  -  -  + ]:         633 :                         (source->length > 0 && source->string_length >= source->length))
      89                 :             :                 {
      90                 :           1 :                         report("Memory management; Source string descriptor is inconsistent");
      91                 :           1 :                         provide(FAILURE);
      92                 :             :                 }
      93                 :             : 
      94                 :             :                 /* In descriptor-to-descriptor string mode, the source contract already
      95                 :             :                    guarantees a cached visible length and a terminator right after it.
      96                 :             :                    Route the copy through fixed-string semantics so the transfer uses exactly
      97                 :             :                    that visible prefix plus one terminator element, instead of rescanning
      98                 :             :                    the whole logical span in search of zero */
      99                 :         633 :                 run(mem_guarded_add(source->string_length,1,&source_total_elements));
     100                 :         633 :                 run(mem_guarded_byte_size(source,source_total_elements,&source_size_bytes));
     101                 :         633 :                 run(mem_copy_fixed_string(destination,source_size_bytes,source->data));
     102                 :             :         } else {
     103                 :           5 :                 run(mem_copy_data(destination,source));
     104                 :             :         }
     105                 :             : 
     106                 :         638 :         provide(status);
     107                 :             : }