KernelLand/Kernel/adt.c

   1 /*
   2  * Acess2 Kernel
   3  *
   4  * adt.c
   5  * - Complex data type code
   6  */
   7 #include <acess.h>
   8 #include <adt.h>
   9
  10
  11 // === CODE ===
  12 // --- Ring Buffers ---
  13 tRingBuffer *RingBuffer_Create(size_t Space)
  14 {
  15         tRingBuffer     *ret = calloc(1, sizeof(tRingBuffer)+Space);
  16         ret->Space = Space;
  17         return ret;
  18 }
  19
  20 size_t RingBuffer_Read(void *Dest, tRingBuffer *Buffer, size_t Length)
  21 {
  22         size_t  tmpLen;
  23
  24         tmpLen = Buffer->Length;        // Changed in Write, so cache it for our read
  25
  26         if(Length > tmpLen)     Length = tmpLen;
  27
  28         if( Buffer->Start + Length > Buffer->Space )
  29         {
  30                  int    endData = Buffer->Space - Buffer->Start;
  31                 memcpy(Dest, &Buffer->Data[Buffer->Start], endData);
  32                 memcpy((Uint8*)Dest + endData, Buffer->Data, Length - endData);
  33         }
  34         else
  35         {
  36                 memcpy(Dest, &Buffer->Data[Buffer->Start], Length);
  37         }
  38
  39         // Lock then modify
  40         SHORTLOCK( &Buffer->Lock );
  41         Buffer->Start += Length;
  42         if( Buffer->Start > Buffer->Space )
  43                 Buffer->Start -= Buffer->Space;
  44         Buffer->Length -= Length;
  45         SHORTREL( &Buffer->Lock );
  46
  47         return Length;
  48 }
  49
  50 size_t RingBuffer_Write(tRingBuffer *Buffer, const void *Source, size_t Length)
  51 {
  52         size_t  bufEnd, endSpace;
  53         size_t  tmpLen, tmpStart;
  54
  55         // Cache Start and Length because _Read can change these
  56         SHORTLOCK( &Buffer->Lock );
  57         tmpStart = Buffer->Start;
  58         tmpLen = Buffer->Length;
  59         SHORTREL( &Buffer->Lock );
  60
  61         bufEnd = (tmpStart + Buffer->Length) % Buffer->Space;
  62         endSpace = Buffer->Space - bufEnd;
  63
  64         // Force to bounds
  65         if(Length > Buffer->Space - tmpLen)     Length = Buffer->Space - tmpLen;
  66
  67         if(endSpace < Length)
  68         {
  69                 memcpy( &Buffer->Data[bufEnd], Source, endSpace );
  70                 memcpy( Buffer->Data, (Uint8*)Source + endSpace, Length - endSpace );
  71         }
  72         else
  73         {
  74                 memcpy( &Buffer->Data[bufEnd], Source, Length );
  75         }
  76
  77         // Lock then modify
  78         SHORTLOCK( &Buffer->Lock );
  79         Buffer->Length += Length;
  80         SHORTREL( &Buffer->Lock );
  81
  82         return Length;
  83 }
  84