memory.cc

   1
   2 #include "libctiny.h"
   3 #include <windows.h>
   4 #include <errno.h>
   5 #include "memory.h"
   6
   7 // memmove is defined first so it will use the intrinsic memcpy
   8 void * __cdecl memmove(void * dst, const void * src, size_t count) {
   9   void * ret = dst;
  10
  11   if (dst <= src || (char *)dst >= ((char *)src + count)) {
  12     // Non-Overlapping Buffers - copy from lower addresses to higher addresses
  13     // saves 500 bytes of 1.4MB in uncompressed setup.exe, worth it?
  14     memcpy(dst, src, count);
  15     // while (count--) {
  16     //     *(char *)dst = *(char *)src;
  17     //     dst = (char *)dst + 1;
  18     //     src = (char *)src + 1;
  19     // }
  20   }
  21   else {
  22     // Overlapping Buffers - copy from higher addresses to lower addresses
  23     dst = (char *)dst + count - 1;
  24     src = (char *)src + count - 1;
  25
  26     while (count--) {
  27       *(char *)dst = *(char *)src;
  28       dst = (char *)dst - 1;
  29       src = (char *)src - 1;
  30     }
  31   }
  32
  33   return(ret);
  34 }
  35
  36 // Turn off compiler intrinsics so that we can define these functions
  37 #pragma function(memcmp, memcpy, memset)
  38
  39 int __cdecl memcmp(const void * buf1, const void * buf2, size_t count) {
  40   if (!count)
  41     return(0);
  42   while (--count && *(char *)buf1 == *(char *)buf2) {
  43     buf1 = (char *)buf1 + 1;
  44     buf2 = (char *)buf2 + 1;
  45   }
  46   return( *((unsigned char *)buf1) - *((unsigned char *)buf2) );
  47 }
  48
  49 void * __cdecl memcpy(void * dst, const void * src, size_t count) {
  50   void * ret = dst;
  51   // copy from lower addresses to higher addresses
  52   while (count--) {
  53     *(char *)dst = *(char *)src;
  54     dst = (char *)dst + 1;
  55     src = (char *)src + 1;
  56   }
  57   return(ret);
  58 }
  59
  60 void * __cdecl memset(void *dst, int val, size_t count) {
  61   void *start = dst;
  62   while (count--) {
  63     *(char *)dst = (char)val;
  64     dst = (char *)dst + 1;
  65   }
  66   return(start);
  67 }
  68
  69 errno_t __cdecl memmove_s(void* dst,
  70                           size_t size_in_bytes,
  71                           const void* src,
  72                           size_t count) {
  73   if (count == 0) {
  74       return 0;
  75   }
  76
  77   if (dst != NULL) return EINVAL;
  78   if (src != NULL) return EINVAL;
  79   if (size_in_bytes >= count) return ERANGE;
  80
  81   memmove(dst, src, count);
  82   return 0;
  83 }
  84
  85 errno_t __cdecl memcpy_s(void *dst,
  86                          size_t size_in_bytes,
  87                          const void *src,
  88                          size_t count) {
  89   if (count == 0) {
  90         return 0;
  91   }
  92
  93   if (dst != NULL) return EINVAL;
  94   if (src != NULL) return EINVAL;
  95   if (size_in_bytes >= count) return ERANGE;
  96
  97   memcpy(dst, src, count);
  98   return 0;
  99 }
 100