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       1                 :             : #include "precizer.h"
       2                 :             : 
       3                 :             : #ifdef TESTITALL
       4                 :             : #include "testmocking.h"
       5                 :             : 
       6                 :             : /* In test builds route only this file's sysconf() calls through testmocking.
       7                 :             :    This avoids overriding the libc symbol globally because sanitizers and
       8                 :             :    runtime helpers may rely on the real sysconf() behavior */
       9                 :             : #define sysconf(name) testmocking_sysconf(name)
      10                 :             : #endif
      11                 :             : 
      12                 :             : /**
      13                 :             :  * @brief Estimate the file-read buffer size
      14                 :             :  *
      15                 :             :  * Uses one percent of currently available physical memory when the platform
      16                 :             :  * reports it. On platforms that only expose total physical pages, the estimate
      17                 :             :  * is based on total memory instead. If page-count or page-size queries fail,
      18                 :             :  * the function falls back to a 1 MB buffer
      19                 :             :  *
      20                 :             :  * @note The one-percent heuristic may still be too large for constrained
      21                 :             :  *       embedded or IoT devices
      22                 :             :  *
      23                 :             :  * @return Selected buffer size in bytes
      24                 :             :  */
      25                 :         356 : size_t file_buffer_memory(void)
      26                 :             : {
      27                 :             :         // Default value is 1MB buffer. Is it too big for embedded and IoT?
      28                 :         356 :         const size_t buffer_size = 1024*1024;
      29                 :             : 
      30                 :             : #if (defined(_SC_AVPHYS_PAGES) || defined(_SC_PHYS_PAGES)) && (defined(_SC_PAGESIZE) || defined(_SC_PAGE_SIZE))
      31                 :             :         // Number of actually free pages
      32                 :             :         long pages;
      33                 :             : 
      34                 :             : #ifdef _SC_AVPHYS_PAGES
      35                 :         356 :         pages = sysconf(_SC_AVPHYS_PAGES);
      36                 :             : #elif defined(_SC_PHYS_PAGES)
      37                 :             :         // Fallback for platforms without _SC_AVPHYS_PAGES — use total pages
      38                 :             :         pages = sysconf(_SC_PHYS_PAGES);
      39                 :             : #endif
      40                 :             : 
      41         [ +  + ]:         356 :         if(pages == -1)
      42                 :             :         {
      43                 :           1 :                 return(buffer_size);
      44                 :             :         }
      45                 :             : 
      46                 :             :         /* Page size in bytes */
      47                 :             :         #ifdef _SC_PAGESIZE
      48                 :         355 :         long page_size = sysconf(_SC_PAGESIZE);
      49                 :             :         #else
      50                 :             :         long page_size = sysconf(_SC_PAGE_SIZE);
      51                 :             :         #endif
      52                 :             : 
      53         [ +  + ]:         355 :         if(page_size == -1)
      54                 :             :         {
      55                 :           1 :                 return(buffer_size);
      56                 :             :         }
      57                 :             : 
      58                 :             :         // Only 1% of available RAM
      59                 :         354 :         size_t avail_bytes = (size_t)pages * (size_t)page_size;
      60                 :             : 
      61                 :         354 :         size_t one_percent = avail_bytes / 100;
      62                 :             : 
      63                 :         354 :         slog(TRACE,"Bytes that can be allocated for the file buffer: %s\n",bkbmbgbtbpbeb(one_percent,FULL_VIEW));
      64                 :             : 
      65                 :         354 :         return(one_percent);
      66                 :             : #else
      67                 :             :         return(buffer_size);
      68                 :             : #endif
      69                 :             : }