// Module initialization routine for Huffman entropy encoding.
static void jinit_lhuff_encoder(jpeg_compress cinfo)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = null;
try
{
entropy = new lhuff_entropy_encoder();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
losslsc.entropy_private = entropy;
losslsc.entropy_start_pass = start_pass_huff_ls;
losslsc.need_optimization_pass = need_optimization_pass_ls;
// Mark tables unallocated
for (int i = 0; i < NUM_HUFF_TBLS; i++)
{
entropy.derived_tbls[i] = null;
#if ENTROPY_OPT_SUPPORTED
entropy.count_ptrs[i] = null;
#endif
}
}
// Finish up at the end of a Huffman-compressed scan.
static void finish_pass_huff_ls(jpeg_compress cinfo)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = (lhuff_entropy_encoder)losslsc.entropy_private;
// Load up working state ... flush_bits needs it
working_state_ls state;
state.output_bytes = cinfo.dest.output_bytes;
state.next_output_byte = cinfo.dest.next_output_byte;
state.free_in_buffer = cinfo.dest.free_in_buffer;
state.cur = entropy.saved;
state.cinfo = cinfo;
// Flush out the last data
if (!flush_bits(ref state))
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CANT_SUSPEND);
}
// Update state
cinfo.dest.output_bytes = state.output_bytes;
cinfo.dest.next_output_byte = state.next_output_byte;
cinfo.dest.free_in_buffer = state.free_in_buffer;
entropy.saved = state.cur;
}
// Finish up a statistics-gathering pass and create the new Huffman tables.
static void finish_pass_gather_ls(jpeg_compress cinfo)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = (lhuff_entropy_encoder)losslsc.entropy_private;
// It's important not to apply jpeg_gen_optimal_table more than once
// per table, because it clobbers the input frequency counts!
bool[] did_dc = new bool[NUM_HUFF_TBLS];
for (int ci = 0; ci < cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr = cinfo.cur_comp_info[ci];
int dctbl = compptr.dc_tbl_no;
if (!did_dc[dctbl])
{
if (cinfo.dc_huff_tbl_ptrs[dctbl] == null)
{
cinfo.dc_huff_tbl_ptrs[dctbl] = jpeg_alloc_huff_table(cinfo);
}
jpeg_gen_optimal_table(cinfo, cinfo.dc_huff_tbl_ptrs[dctbl], entropy.count_ptrs[dctbl]);
did_dc[dctbl] = true;
}
}
}
// Initialize for a Huffman-compressed scan.
// If gather_statistics is true, we do not output anything during the scan,
// just count the Huffman symbols used and generate Huffman code tables.
static void start_pass_huff_ls(jpeg_compress cinfo, bool gather_statistics)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = (lhuff_entropy_encoder)losslsc.entropy_private;
if (gather_statistics)
{
#if ENTROPY_OPT_SUPPORTED
losslsc.entropy_encode_mcus = encode_mcus_gather_ls;
losslsc.entropy_finish_pass = finish_pass_gather_ls;
#else
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_NOT_COMPILED);
#endif
}
else
{
losslsc.entropy_encode_mcus = encode_mcus_huff_ls;
losslsc.entropy_finish_pass = finish_pass_huff_ls;
}
for (int ci = 0; ci < cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr = cinfo.cur_comp_info[ci];
int dctbl = compptr.dc_tbl_no;
if (gather_statistics)
{
#if ENTROPY_OPT_SUPPORTED
// Check for invalid table indexes
// (make_c_derived_tbl does this in the other path)
if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS)
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, dctbl);
}
// Allocate and zero the statistics tables
// Note that jpeg_gen_optimal_table expects 257 entries in each table!
if (entropy.count_ptrs[dctbl] == null)
{
entropy.count_ptrs[dctbl] = new int[257];
}
else
{
for (int i = 0; i < 257; i++)
{
entropy.count_ptrs[dctbl][i] = 0;
}
}
#endif
}
else
{
// Compute derived values for Huffman tables
// We may do this more than once for a table, but it's not expensive
jpeg_make_c_derived_tbl(cinfo, true, dctbl, ref entropy.derived_tbls[dctbl]);
}
}
// Precalculate encoding info for each sample in an MCU of this scan
int ptrn = 0;
for (int sampn = 0; sampn < cinfo.block_in_MCU;)
{
jpeg_component_info compptr = cinfo.cur_comp_info[cinfo.MCU_membership[sampn]];
int ci = compptr.component_index;
//ci=cinfo.MCU_membership[sampn];
//compptr=cinfo.cur_comp_info[ci];
for (int yoffset = 0; yoffset < compptr.MCU_height; yoffset++, ptrn++)
{
// Precalculate the setup info for each input pointer
entropy.input_ptr_info[ptrn].ci = ci;
entropy.input_ptr_info[ptrn].yoffset = yoffset;
entropy.input_ptr_info[ptrn].MCU_width = compptr.MCU_width;
for (int xoffset = 0; xoffset < compptr.MCU_width; xoffset++, sampn++)
{
// Precalculate the input pointer index for each sample
entropy.input_ptr_index[sampn] = ptrn;
// Precalculate which tables to use for each sample
entropy.cur_tbls[sampn] = entropy.derived_tbls[compptr.dc_tbl_no];
entropy.cur_counts[sampn] = entropy.count_ptrs[compptr.dc_tbl_no];
}
}
}
entropy.num_input_ptrs = ptrn;
// Initialize bit buffer to empty
entropy.saved.put_buffer = 0;
entropy.saved.put_bits = 0;
// Initialize restart stuff
entropy.restarts_to_go = cinfo.restart_interval;
entropy.next_restart_num = 0;
}
// Huffman coding optimization.
//
// We first scan the supplied data and count the number of uses of each symbol
// that is to be Huffman-coded. (This process MUST agree with the code above.)
// Then we build a Huffman coding tree for the observed counts.
// Symbols which are not needed at all for the particular image are not
// assigned any code, which saves space in the DHT marker as well as in
// the compressed data.
#if ENTROPY_OPT_SUPPORTED
// Trial-encode one nMCU's worth of Huffman-compressed differences.
// No data is actually output, so no suspension return is possible.
static uint encode_mcus_gather_ls(jpeg_compress cinfo, int[][][] diff_buf, uint MCU_row_num, uint MCU_col_num, uint nMCU)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = (lhuff_entropy_encoder)losslsc.entropy_private;
// Take care of restart intervals if needed
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
entropy.restarts_to_go = cinfo.restart_interval; // Update restart state
}
entropy.restarts_to_go--;
}
// Set input pointer locations based on MCU_col_num
for (int ptrn = 0; ptrn < entropy.num_input_ptrs; ptrn++)
{
int ci = entropy.input_ptr_info[ptrn].ci;
int yoffset = entropy.input_ptr_info[ptrn].yoffset;
int MCU_width = entropy.input_ptr_info[ptrn].MCU_width;
entropy.input_ptr[ptrn] = diff_buf[ci][MCU_row_num + yoffset];
entropy.input_ptr_ind[ptrn] = (int)MCU_col_num * MCU_width;
}
for (uint mcu_num = 0; mcu_num < nMCU; mcu_num++)
{
// Inner loop handles the samples in the MCU
for (int sampn = 0; sampn < cinfo.block_in_MCU; sampn++)
{
c_derived_tbl dctbl = entropy.cur_tbls[sampn];
int[] counts = entropy.cur_counts[sampn];
// Encode the difference per section H.1.2.2
// Input the sample difference
int temp3 = entropy.input_ptr_index[sampn];
int temp = entropy.input_ptr[temp3][entropy.input_ptr_ind[temp3]++];
if ((temp & 0x8000) != 0)
{ // instead of temp < 0
temp = (-temp) & 0x7FFF; // absolute value, mod 2^16
if (temp == 0)
{
temp = 0x8000; // special case: magnitude = 32768
}
}
else
{
temp &= 0x7FFF; // abs value mod 2^16
}
// Find the number of bits needed for the magnitude of the difference
int nbits = 0;
while (temp != 0)
{
nbits++;
temp >>= 1;
}
// Check for out-of-range difference values.
if (nbits > MAX_DIFF_BITS)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_DIFF);
}
// Count the Huffman symbol for the number of bits
counts[nbits]++;
}
}
return(nMCU);
}
// Encode and output one nMCU's worth of Huffman-compressed differences.
static uint encode_mcus_huff_ls(jpeg_compress cinfo, int[][][] diff_buf, uint MCU_row_num, uint MCU_col_num, uint nMCU)
{
jpeg_lossless_c_codec losslsc = (jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy = (lhuff_entropy_encoder)losslsc.entropy_private;
// Load up working state
working_state_ls state;
state.output_bytes = cinfo.dest.output_bytes;
state.next_output_byte = cinfo.dest.next_output_byte;
state.free_in_buffer = cinfo.dest.free_in_buffer;
state.cur = entropy.saved;
state.cinfo = cinfo;
// Emit restart marker if needed
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
if (!emit_restart(ref state, entropy.next_restart_num))
{
return(0);
}
}
}
// Set input pointer locations based on MCU_col_num
for (int ptrn = 0; ptrn < entropy.num_input_ptrs; ptrn++)
{
int ci = entropy.input_ptr_info[ptrn].ci;
int yoffset = entropy.input_ptr_info[ptrn].yoffset;
int MCU_width = entropy.input_ptr_info[ptrn].MCU_width;
entropy.input_ptr[ptrn] = diff_buf[ci][MCU_row_num + yoffset];
entropy.input_ptr_ind[ptrn] = (int)MCU_col_num * MCU_width;
}
for (uint mcu_num = 0; mcu_num < nMCU; mcu_num++)
{
// Inner loop handles the samples in the MCU
for (int sampn = 0; sampn < cinfo.block_in_MCU; sampn++)
{
c_derived_tbl dctbl = entropy.cur_tbls[sampn];
// Encode the difference per section H.1.2.2
// Input the sample difference
int temp3 = entropy.input_ptr_index[sampn];
int temp = entropy.input_ptr[temp3][entropy.input_ptr_ind[temp3]++];
int temp2;
if ((temp & 0x8000) != 0)
{ // instead of temp < 0
temp = (-temp) & 0x7FFF; // absolute value, mod 2^16
if (temp == 0)
{
temp2 = temp = 0x8000; // special case: magnitude = 32768
}
temp2 = ~temp; // one's complement of magnitude
}
else
{
temp &= 0x7FFF; // abs value mod 2^16
temp2 = temp; // magnitude
}
// Find the number of bits needed for the magnitude of the difference
int nbits = 0;
while (temp != 0)
{
nbits++;
temp >>= 1;
}
// Check for out-of-range difference values.
if (nbits > MAX_DIFF_BITS)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_DIFF);
}
// Emit the Huffman-coded symbol for the number of bits
if (!emit_bits(ref state, dctbl.ehufco[nbits], dctbl.ehufsi[nbits]))
{
return(mcu_num);
}
// Emit that number of bits of the value, if positive,
// or the complement of its magnitude, if negative.
if (nbits != 0 && // emit_bits rejects calls with size 0
nbits != 16) // special case: no bits should be emitted
{
if (!emit_bits(ref state, (uint)temp2, nbits))
{
return(mcu_num);
}
}
}
// Completed MCU, so update state
cinfo.dest.output_bytes = state.output_bytes;
cinfo.dest.next_output_byte = state.next_output_byte;
cinfo.dest.free_in_buffer = state.free_in_buffer;
entropy.saved = state.cur;
// Update restart-interval state too
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
entropy.restarts_to_go = cinfo.restart_interval;
entropy.next_restart_num++;
entropy.next_restart_num &= 7;
}
entropy.restarts_to_go--;
}
}
return(nMCU);
}
// Module initialization routine for Huffman entropy encoding.
static void jinit_lhuff_encoder(jpeg_compress cinfo)
{
jpeg_lossless_c_codec losslsc=(jpeg_lossless_c_codec)cinfo.coef;
lhuff_entropy_encoder entropy=null;
try
{
entropy=new lhuff_entropy_encoder();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
losslsc.entropy_private=entropy;
losslsc.entropy_start_pass=start_pass_huff_ls;
losslsc.need_optimization_pass=need_optimization_pass_ls;
// Mark tables unallocated
for(int i=0; i<NUM_HUFF_TBLS; i++)
{
entropy.derived_tbls[i]=null;
#if ENTROPY_OPT_SUPPORTED
entropy.count_ptrs[i]=null;
#endif
}
}
