15.07

2026-01-31 20:24:05 -06:00 · 2015-09-22 00:00:00 +00:00
parent cba375916f
commit f6444c3256
96 changed files with 7301 additions and 2409 deletions
@@ -0,0 +1,129 @@
+// XpressDecoder.cpp
+
+#include "StdAfx.h"
+
+// #include <stdio.h>
+
+#include "../../../C/CpuArch.h"
+
+#include "HuffmanDecoder.h"
+
+namespace NCompress {
+namespace NXpress {
+
+struct CBitStream
+{
+  UInt32 Value;
+  unsigned BitPos;
+
+  UInt32 GetValue(unsigned numBits) const
+  {
+    return (Value >> (BitPos - numBits)) & ((1 << numBits) - 1);
+  }
+  
+  void MovePos(unsigned numBits)
+  {
+    BitPos -= numBits;
+  }
+};
+
+#define BIT_STREAM_NORMALIZE \
+    if (bs.BitPos < 16) { \
+      if (in >= lim) return S_FALSE; \
+      bs.Value = (bs.Value << 16) | GetUi16(in); \
+      in += 2; bs.BitPos += 16; }
+ 
+const unsigned kNumHuffBits = 15;
+const unsigned kNumLenSlots = 16;
+const unsigned kNumPosSlots = 16;
+const unsigned kNumSyms = 256 + kNumPosSlots * kNumLenSlots;
+
+HRESULT Decode(const Byte *in, size_t inSize, Byte *out, size_t outSize)
+{
+  NCompress::NHuffman::CDecoder<kNumHuffBits, kNumSyms> huff;
+  
+  if (inSize < kNumSyms / 2 + 4)
+    return S_FALSE;
+  {
+    Byte levels[kNumSyms];
+    for (unsigned i = 0; i < kNumSyms / 2; i++)
+    {
+      Byte b = in[i];
+      levels[i * 2] = (Byte)(b & 0xF);
+      levels[i * 2 + 1] = (Byte)(b >> 4);
+    }
+    if (!huff.BuildFull(levels))
+      return S_FALSE;
+  }
+
+
+  CBitStream bs;
+
+  const Byte *lim = in + inSize - 1;
+
+  in += kNumSyms / 2;
+  bs.Value = (GetUi16(in) << 16) | GetUi16(in + 2);
+  in += 4;
+  bs.BitPos = 32;
+
+  size_t pos = 0;
+
+  for (;;)
+  {
+    // printf("\n%d", pos);
+    UInt32 sym = huff.DecodeFull(&bs);
+    // printf(" sym = %d", sym);
+    BIT_STREAM_NORMALIZE
+
+    if (pos >= outSize)
+      return (sym == 256 && in == lim + 1) ? S_OK : S_FALSE;
+
+    if (sym < 256)
+      out[pos++] = (Byte)sym;
+    else
+    {
+      sym -= 256;
+      UInt32 dist = sym / kNumLenSlots;
+      UInt32 len = sym & (kNumLenSlots - 1);
+      
+      if (len == kNumLenSlots - 1)
+      {
+        if (in > lim)
+          return S_FALSE;
+        len = *in++;
+        if (len == 0xFF)
+        {
+          if (in >= lim)
+            return S_FALSE;
+          len = GetUi16(in);
+          in += 2;
+        }
+        else
+          len += kNumLenSlots - 1;
+      }
+
+      bs.BitPos -= dist;
+      dist = (UInt32)1 << dist;
+      dist += ((bs.Value >> bs.BitPos) & (dist - 1));
+
+      BIT_STREAM_NORMALIZE
+      
+      if (len > outSize - pos)
+        return S_FALSE;
+      if (dist > pos)
+        return S_FALSE;
+
+      Byte *dest = out + pos;
+      const Byte *src = dest - dist;
+      pos += len + 3;
+      len += 1;
+      *dest++ = *src++;
+      *dest++ = *src++;
+      do
+        *dest++ = *src++;
+      while (--len);
+    }
+  }
+}
+
+}}