private static void LZ4_compressCtx_FrameHeader(
byte[] dst,
ref int dst_p,
LZ4F_preferences_t prefs)
{
/* Magic Number */
Poke4(dst, dst_p, MAGICNUMBER);
dst_p += 4;
/* FLG Byte */
dst[dst_p++] = (byte)(((1 & _2BITS) << 6) /* Version('01') */
+ (((byte)prefs.frameInfo.blockMode & _1BIT) << 5)
+ (((byte)prefs.frameInfo.blockChecksumFlag & _1BIT) << 4)
+ ((prefs.frameInfo.contentSize > 0 ? 1 : 0) << 3)
+ (((byte)prefs.frameInfo.contentChecksumFlag & _1BIT) << 2)
+ (prefs.frameInfo.dictID > 0 ? 1 : 0));
/* BD Byte */
dst[dst_p++] = (byte)(((byte)prefs.frameInfo.blockSizeID & _3BITS) << 4);
/* Optional Frame content size field */
if (prefs.frameInfo.contentSize != 0)
{
Poke8(dst, dst_p, prefs.frameInfo.contentSize);
dst_p += 8;
//cctxPtr->totalInSize = 0;
}
/* Optional dictionary ID field */
if (prefs.frameInfo.dictID != 0)
{
Poke4(dst, dst_p, prefs.frameInfo.dictID);
dst_p += 8;
}
/* Header CRC Byte */
dst[dst_p] = LZ4F_headerChecksum(dst, 0, dst_p);
dst_p++;
}
private static int LZ4_compress64kCtx_safe32(
ushort[] hash_table,
byte[] src,
byte[] dst,
int src_0,
int dst_0,
int src_len,
int dst_maxlen,
ref LZ4F_preferences_t prefs)
{
unchecked
{
var debruijn32 = DEBRUIJN_TABLE_32;
int _i;
// ---- preprocessed source start here ----
// r93
var src_p = src_0;
var src_anchor = src_p;
var src_base = src_p;
var src_end = src_p + src_len;
var src_mflimit = src_end - MFLIMIT;
var dst_p = dst_0;
var dst_end = dst_p + dst_maxlen;
var src_LASTLITERALS = src_end - LASTLITERALS;
var src_LASTLITERALS_1 = src_LASTLITERALS - 1;
var src_LASTLITERALS_STEPSIZE_1 = src_LASTLITERALS - (STEPSIZE_32 - 1);
var dst_LASTLITERALS_1 = dst_end - (1 + LASTLITERALS);
var dst_LASTLITERALS_3 = dst_end - (2 + 1 + LASTLITERALS);
int len, length;
uint h, h_fwd;
// Init
if (src_len < MINLENGTH)
{
goto _last_literals;
}
// First Byte
src_p++;
h_fwd = (((Peek4(src, src_p)) * 2654435761u) >> HASH64K_ADJUST);
// Main Loop
while (true)
{
var findMatchAttempts = (1 << SKIPSTRENGTH) + 3;
var src_p_fwd = src_p;
int src_ref;
int dst_token;
// Find a match
do
{
h = h_fwd;
var step = findMatchAttempts++ >> SKIPSTRENGTH;
src_p = src_p_fwd;
src_p_fwd = src_p + step;
if (src_p_fwd > src_mflimit)
{
goto _last_literals;
}
h_fwd = (((Peek4(src, src_p_fwd)) * 2654435761u) >> HASH64K_ADJUST);
src_ref = src_base + hash_table[h];
hash_table[h] = (ushort)(src_p - src_base);
} while (!Equal4(src, src_ref, src_p));
// Catch up
while ((src_p > src_anchor) && (src_ref > src_0) && (src[src_p - 1] == src[src_ref - 1]))
{
src_p--;
src_ref--;
}
// Encode Literal length
length = (src_p - src_anchor);
dst_token = dst_p++;
if (dst_p + length + (length >> 8) > dst_LASTLITERALS_3)
{
return(0); // Check output limit
}
if (length >= RUN_MASK)
{
len = length - RUN_MASK;
dst[dst_token] = (RUN_MASK << ML_BITS);
if (len > 254)
{
do
{
dst[dst_p++] = 255;
len -= 255;
} while (len > 254);
dst[dst_p++] = (byte)len;
BlockCopy(src, src_anchor, dst, dst_p, length);
dst_p += length;
goto _next_match;
}
else
{
dst[dst_p++] = (byte)len;
}
}
else
{
dst[dst_token] = (byte)(length << ML_BITS);
}
// Copy Literals
if (length > 0)
{
_i = dst_p + length;
WildCopy(src, src_anchor, dst, dst_p, _i);
dst_p = _i;
}
_next_match:
// Encode Offset
Poke2(dst, dst_p, (ushort)(src_p - src_ref));
dst_p += 2;
// Start Counting
src_p += MINMATCH;
src_ref += MINMATCH; // MinMatch verified
src_anchor = src_p;
while (src_p < src_LASTLITERALS_STEPSIZE_1)
{
var diff = (int)Xor4(src, src_ref, src_p);
if (diff == 0)
{
src_p += STEPSIZE_32;
src_ref += STEPSIZE_32;
continue;
}
src_p += debruijn32[((uint)((diff) & -(diff)) * 0x077CB531u) >> 27];
goto _endCount;
}
if ((src_p < src_LASTLITERALS_1) && (Equal2(src, src_ref, src_p)))
{
src_p += 2;
src_ref += 2;
}
if ((src_p < src_LASTLITERALS) && (src[src_ref] == src[src_p]))
{
src_p++;
}
_endCount:
// Encode MatchLength
len = (src_p - src_anchor);
if (dst_p + (len >> 8) > dst_LASTLITERALS_1)
{
return(0); // Check output limit
}
if (len >= ML_MASK)
{
dst[dst_token] += ML_MASK;
len -= ML_MASK;
for (; len > 509; len -= 510)
{
dst[dst_p++] = 255;
dst[dst_p++] = 255;
}
if (len > 254)
{
len -= 255;
dst[dst_p++] = 255;
}
dst[dst_p++] = (byte)len;
}
else
{
dst[dst_token] += (byte)len;
}
// Test end of chunk
if (src_p > src_mflimit)
{
src_anchor = src_p;
break;
}
// Fill table
hash_table[(((Peek4(src, src_p - 2)) * 2654435761u) >> HASH64K_ADJUST)] = (ushort)(src_p - 2 - src_base);
// Test next position
h = (((Peek4(src, src_p)) * 2654435761u) >> HASH64K_ADJUST);
src_ref = src_base + hash_table[h];
hash_table[h] = (ushort)(src_p - src_base);
if (Equal4(src, src_ref, src_p))
{
dst_token = dst_p++;
dst[dst_token] = 0;
goto _next_match;
}
// Prepare next loop
src_anchor = src_p++;
h_fwd = (((Peek4(src, src_p)) * 2654435761u) >> HASH64K_ADJUST);
}
_last_literals:
// Encode Last Literals
var lastRun = (src_end - src_anchor);
if (dst_p + lastRun + 1 + (lastRun - RUN_MASK + 255) / 255 > dst_end)
{
return(0);
}
if (lastRun >= RUN_MASK)
{
dst[dst_p++] = (RUN_MASK << ML_BITS);
lastRun -= RUN_MASK;
for (; lastRun > 254; lastRun -= 255)
{
dst[dst_p++] = 255;
}
dst[dst_p++] = (byte)lastRun;
}
else
{
dst[dst_p++] = (byte)(lastRun << ML_BITS);
}
BlockCopy(src, src_anchor, dst, dst_p, src_end - src_anchor);
dst_p += src_end - src_anchor;
// End
return((dst_p) - dst_0);
}
}
private static void LZ4_compressCtx_FrameFooter(
byte[] dst,
ref int dst_p,
LZ4F_preferences_t prefs)
{
}
