private static unsafe void BrotliBuildMetaBlockGreedyInternal(
ref MemoryManager m, byte *ringbuffer, size_t pos, size_t mask,
byte prev_byte, byte prev_byte2, ContextType literal_context_mode,
size_t num_contexts, uint *static_context_map,
Command *commands, size_t n_commands, MetaBlockSplit *mb)
{
lit_blocks_union lit_blocks = new lit_blocks_union();
BlockSplitterCommand cmd_blocks;
BlockSplitterDistance dist_blocks;
size_t num_literals = 0;
size_t i;
for (i = 0; i < n_commands; ++i)
{
num_literals += commands[i].insert_len_;
}
if (num_contexts == 1)
{
BlockSplitterLiteral.InitBlockSplitter(ref m, (BlockSplitterLiteral *)&lit_blocks, 256, 512, 400.0,
num_literals, &mb->literal_split, &mb->literal_histograms,
&mb->literal_histograms_size);
}
else
{
InitContextBlockSplitter(ref m, &lit_blocks.ctx, 256, num_contexts, 512, 400.0,
num_literals, &mb->literal_split, &mb->literal_histograms,
&mb->literal_histograms_size);
}
BlockSplitterCommand.InitBlockSplitter(ref m, &cmd_blocks, BROTLI_NUM_COMMAND_SYMBOLS, 1024,
500.0, n_commands, &mb->command_split, &mb->command_histograms,
&mb->command_histograms_size);
BlockSplitterDistance.InitBlockSplitter(ref m, &dist_blocks, 64, 512, 100.0, n_commands,
&mb->distance_split, &mb->distance_histograms,
&mb->distance_histograms_size);
for (i = 0; i < n_commands; ++i)
{
Command cmd = commands[i];
size_t j;
BlockSplitterCommand.BlockSplitterAddSymbol(&cmd_blocks, cmd.cmd_prefix_);
for (j = cmd.insert_len_; j != 0; --j)
{
byte literal = ringbuffer[pos & mask];
if (num_contexts == 1)
{
BlockSplitterLiteral.BlockSplitterAddSymbol((BlockSplitterLiteral *)&lit_blocks, literal);
}
else
{
size_t context = Context(prev_byte, prev_byte2, literal_context_mode);
ContextBlockSplitterAddSymbol(&lit_blocks.ctx, ref m, literal,
static_context_map[context]);
}
prev_byte2 = prev_byte;
prev_byte = literal;
++pos;
}
pos += CommandCopyLen(&cmd);
if (CommandCopyLen(&cmd) != 0)
{
prev_byte2 = ringbuffer[(pos - 2) & mask];
prev_byte = ringbuffer[(pos - 1) & mask];
if (cmd.cmd_prefix_ >= 128)
{
BlockSplitterDistance.BlockSplitterAddSymbol(&dist_blocks, cmd.dist_prefix_);
}
}
}
if (num_contexts == 1)
{
BlockSplitterLiteral.BlockSplitterFinishBlock(
(BlockSplitterLiteral *)&lit_blocks, /* is_final = */ true);
}
else
{
ContextBlockSplitterFinishBlock(
&lit_blocks.ctx, ref m, /* is_final = */ true);
}
BlockSplitterCommand.BlockSplitterFinishBlock(&cmd_blocks, /* is_final = */ true);
BlockSplitterDistance.BlockSplitterFinishBlock(&dist_blocks, /* is_final = */ true);
if (num_contexts > 1)
{
MapStaticContexts(ref m, num_contexts, static_context_map, mb);
}
}
private static unsafe void BrotliSplitBlock(ref MemoryManager m,
Command *cmds,
size_t num_commands,
byte *data,
size_t pos,
size_t mask,
BrotliEncoderParams *params_,
BlockSplit *literal_split,
BlockSplit *insert_and_copy_split,
BlockSplit *dist_split)
{
{
size_t literals_count = CountLiterals(cmds, num_commands);
byte * literals = (byte *)BrotliAllocate(ref m, literals_count * sizeof(byte));
/* Create a continuous array of literals. */
CopyLiteralsToByteArray(cmds, num_commands, data, pos, mask, literals);
/* Create the block split on the array of literals.
* Literal histograms have alphabet size 256. */
BlockSplitterLiteral.SplitByteVector(
ref m, literals, literals_count,
kSymbolsPerLiteralHistogram, kMaxLiteralHistograms,
kLiteralStrideLength, kLiteralBlockSwitchCost, params_,
literal_split);
BrotliFree(ref m, literals);
}
{
/* Compute prefix codes for commands. */
ushort *insert_and_copy_codes = (ushort *)BrotliAllocate(ref m, num_commands * sizeof(ushort));
size_t i;
for (i = 0; i < num_commands; ++i)
{
insert_and_copy_codes[i] = cmds[i].cmd_prefix_;
}
/* Create the block split on the array of command prefixes. */
BlockSplitterCommand.SplitByteVector(
ref m, insert_and_copy_codes, num_commands,
kSymbolsPerCommandHistogram, kMaxCommandHistograms,
kCommandStrideLength, kCommandBlockSwitchCost, params_,
insert_and_copy_split);
/* TODO: reuse for distances? */
BrotliFree(ref m, insert_and_copy_codes);
}
{
/* Create a continuous array of distance prefixes. */
ushort *distance_prefixes = (ushort *)BrotliAllocate(ref m, num_commands * sizeof(ushort));
size_t j = 0;
size_t i;
for (i = 0; i < num_commands; ++i)
{
Command *cmd = &cmds[i];
if (CommandCopyLen(cmd) != 0 && cmd->cmd_prefix_ >= 128)
{
distance_prefixes[j++] = cmd->dist_prefix_;
}
}
/* Create the block split on the array of distance prefixes. */
BlockSplitterDistance.SplitByteVector(
ref m, distance_prefixes, j,
kSymbolsPerDistanceHistogram, kMaxCommandHistograms,
kCommandStrideLength, kDistanceBlockSwitchCost, params_,
dist_split);
BrotliFree(ref m, distance_prefixes);
}
}