add CHD support.

[pcsx_rearmed.git] / deps / lzma-16.04 / C / Delta.c

/* Delta.c -- Delta converter\r
2009-05-26 : Igor Pavlov : Public domain */\r
\r
#include "Precomp.h"\r
\r
#include "Delta.h"\r
\r
void Delta_Init(Byte *state)\r
{\r
  unsigned i;\r
  for (i = 0; i < DELTA_STATE_SIZE; i++)\r
    state[i] = 0;\r
}\r
\r
static void MyMemCpy(Byte *dest, const Byte *src, unsigned size)\r
{\r
  unsigned i;\r
  for (i = 0; i < size; i++)\r
    dest[i] = src[i];\r
}\r
\r
void Delta_Encode(Byte *state, unsigned delta, Byte *data, SizeT size)\r
{\r
  Byte buf[DELTA_STATE_SIZE];\r
  unsigned j = 0;\r
  MyMemCpy(buf, state, delta);\r
  {\r
    SizeT i;\r
    for (i = 0; i < size;)\r
    {\r
      for (j = 0; j < delta && i < size; i++, j++)\r
      {\r
        Byte b = data[i];\r
        data[i] = (Byte)(b - buf[j]);\r
        buf[j] = b;\r
      }\r
    }\r
  }\r
  if (j == delta)\r
    j = 0;\r
  MyMemCpy(state, buf + j, delta - j);\r
  MyMemCpy(state + delta - j, buf, j);\r
}\r
\r
void Delta_Decode(Byte *state, unsigned delta, Byte *data, SizeT size)\r
{\r
  Byte buf[DELTA_STATE_SIZE];\r
  unsigned j = 0;\r
  MyMemCpy(buf, state, delta);\r
  {\r
    SizeT i;\r
    for (i = 0; i < size;)\r
    {\r
      for (j = 0; j < delta && i < size; i++, j++)\r
      {\r
        buf[j] = data[i] = (Byte)(buf[j] + data[i]);\r
      }\r
    }\r
  }\r
  if (j == delta)\r
    j = 0;\r
  MyMemCpy(state, buf + j, delta - j);\r
  MyMemCpy(state + delta - j, buf, j);\r
}\r