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 void RingBuffer_Free(tRingBuffer *Buffer)
  21 {
  22         free(Buffer);
  23 }
  24
  25 size_t RingBuffer_Read(void *Dest, tRingBuffer *Buffer, size_t Length)
  26 {
  27         size_t  tmpLen;
  28
  29         tmpLen = Buffer->Length;        // Changed in Write, so cache it for our read
  30
  31         if(Length > tmpLen)     Length = tmpLen;
  32
  33         if( Buffer->Start + Length > Buffer->Space )
  34         {
  35                  int    endData = Buffer->Space - Buffer->Start;
  36                 memcpy(Dest, &Buffer->Data[Buffer->Start], endData);
  37                 memcpy((Uint8*)Dest + endData, Buffer->Data, Length - endData);
  38         }
  39         else
  40         {
  41                 memcpy(Dest, &Buffer->Data[Buffer->Start], Length);
  42         }
  43
  44         // Lock then modify
  45         SHORTLOCK( &Buffer->Lock );
  46         Buffer->Start += Length;
  47         if( Buffer->Start > Buffer->Space )
  48                 Buffer->Start -= Buffer->Space;
  49         Buffer->Length -= Length;
  50         SHORTREL( &Buffer->Lock );
  51
  52         return Length;
  53 }
  54
  55 size_t RingBuffer_Write(tRingBuffer *Buffer, const void *Source, size_t Length)
  56 {
  57         size_t  bufEnd, endSpace;
  58         size_t  tmpLen, tmpStart;
  59
  60         // Cache Start and Length because _Read can change these
  61         SHORTLOCK( &Buffer->Lock );
  62         tmpStart = Buffer->Start;
  63         tmpLen = Buffer->Length;
  64         SHORTREL( &Buffer->Lock );
  65
  66         bufEnd = (tmpStart + Buffer->Length) % Buffer->Space;
  67         endSpace = Buffer->Space - bufEnd;
  68
  69         // Force to bounds
  70         if(Length > Buffer->Space - tmpLen)     Length = Buffer->Space - tmpLen;
  71
  72         if(endSpace < Length)
  73         {
  74                 memcpy( &Buffer->Data[bufEnd], Source, endSpace );
  75                 memcpy( Buffer->Data, (Uint8*)Source + endSpace, Length - endSpace );
  76         }
  77         else
  78         {
  79                 memcpy( &Buffer->Data[bufEnd], Source, Length );
  80         }
  81
  82         // Lock then modify
  83         SHORTLOCK( &Buffer->Lock );
  84         Buffer->Length += Length;
  85         SHORTREL( &Buffer->Lock );
  86
  87         return Length;
  88 }
  89