// Out-of-line code for Huffman code decoding.
static int jpeg_huff_decode(ref bitread_working_state state, ulong get_buffer, int bits_left, d_derived_tbl htbl, int min_bits)
{
int l=min_bits;
// HUFF_DECODE has determined that the code is at least min_bits
// bits long, so fetch that many bits in one swoop.
//was CHECK_BIT_BUFFER(*state, l, return -1);
if(bits_left<l)
{
if(!jpeg_fill_bit_buffer(ref state, get_buffer, bits_left, l)) return -1;
get_buffer=state.get_buffer;
bits_left=state.bits_left;
}
//was code = GET_BITS(l);
int code=((int)(get_buffer>>(bits_left-=l)))&((1<<l)-1);
// Collect the rest of the Huffman code one bit at a time.
// This is per Figure F.16 in the JPEG spec.
while(code>htbl.maxcode[l])
{
code<<=1;
//was CHECK_BIT_BUFFER(*state, 1, return -1);
if(bits_left<1)
{
if(!jpeg_fill_bit_buffer(ref state, get_buffer, bits_left, 1)) return -1;
get_buffer=state.get_buffer;
bits_left=state.bits_left;
}
//was code |= GET_BITS(1);
code|=((int)(get_buffer>>(bits_left-=1)))&1;
l++;
}
// Unload the local registers
state.get_buffer=get_buffer;
state.bits_left=bits_left;
// With garbage input we may reach the sentinel value l = 17.
if(l>16)
{
WARNMS(state.cinfo, J_MESSAGE_CODE.JWRN_HUFF_BAD_CODE);
return 0; // fake a zero as the safest result
}
return htbl.pub.huffval[(int)(code+htbl.valoffset[l])];
}
// Expand a Huffman table definition into the derived format
// Compute the derived values for a Huffman table.
// This routine also performs some validation checks on the table.
static void jpeg_make_d_derived_tbl(jpeg_decompress cinfo, bool isDC, int tblno, ref d_derived_tbl pdtbl)
{
// Note that huffsize[] and huffcode[] are filled in code-length order,
// paralleling the order of the symbols themselves in htbl.huffval[].
// Find the input Huffman table
if(tblno<0||tblno>=NUM_HUFF_TBLS) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tblno);
JHUFF_TBL htbl=isDC?cinfo.dc_huff_tbl_ptrs[tblno]:cinfo.ac_huff_tbl_ptrs[tblno];
if(htbl==null) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tblno);
// Allocate a workspace if we haven't already done so.
if(pdtbl==null)
{
try
{
pdtbl=new d_derived_tbl();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
d_derived_tbl dtbl=pdtbl;
dtbl.pub=htbl; // fill in back link
// Figure C.1: make table of Huffman code length for each symbol
byte[] huffsize=new byte[257];
int p=0;
for(byte l=1; l<=16; l++)
{
int i=(int)htbl.bits[l];
if(i<0||p+i>256) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE); // protect against table overrun
while((i--)!=0) huffsize[p++]=l;
}
huffsize[p]=0;
int numsymbols=p;
// Figure C.2: generate the codes themselves
// We also validate that the counts represent a legal Huffman code tree.
uint[] huffcode=new uint[257];
uint code=0;
int si=huffsize[0];
p=0;
while(huffsize[p]!=0)
{
while(((int)huffsize[p])==si)
{
huffcode[p++]=code;
code++;
}
// code is now 1 more than the last code used for codelength si; but
// it must still fit in si bits, since no code is allowed to be all ones.
if(((int)code)>=(1<<si)) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE);
code<<=1;
si++;
}
// Figure F.15: generate decoding tables for bit-sequential decoding
p=0;
for(int l=1; l<=16; l++)
{
if(htbl.bits[l]!=0)
{
// valoffset[l] = huffval[] index of 1st symbol of code length l,
// minus the minimum code of length l
dtbl.valoffset[l]=(int)p-(int)huffcode[p];
p+=htbl.bits[l];
dtbl.maxcode[l]=(int)huffcode[p-1]; // maximum code of length l
}
else
{
dtbl.maxcode[l]=-1; // -1 if no codes of this length
}
}
dtbl.maxcode[17]=0xFFFFF; // ensures jpeg_huff_decode terminates
// Compute lookahead tables to speed up decoding.
// First we set all the table entries to 0, indicating "too long";
// then we iterate through the Huffman codes that are short enough and
// fill in all the entries that correspond to bit sequences starting
// with that code.
for(int i=0; i<dtbl.look_nbits.Length; i++) dtbl.look_nbits[i]=0;
p=0;
for(int l=1; l<=HUFF_LOOKAHEAD; l++)
{
for(int i=1; i<=(int)htbl.bits[l]; i++, p++)
{
// l = current code's length, p = its index in huffcode[] & huffval[].
// Generate left-justified code followed by all possible bit sequences
int lookbits=((int)huffcode[p])<<(HUFF_LOOKAHEAD-l);
for(int ctr=1<<(HUFF_LOOKAHEAD-l); ctr>0; ctr--)
{
dtbl.look_nbits[lookbits]=l;
dtbl.look_sym[lookbits]=htbl.huffval[p];
lookbits++;
}
}
}
// Validate symbols as being reasonable.
// For AC tables, we make no check, but accept all byte values 0..255.
// For DC tables, we require the symbols to be in range 0..16.
// (Tighter bounds could be applied depending on the data depth and mode,
// but this is sufficient to ensure safe decoding.)
if(isDC)
{
for(int i=0; i<numsymbols; i++)
{
int sym=htbl.huffval[i];
if(sym<0||sym>16) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE);
}
}
}
// Expand a Huffman table definition into the derived format
// Compute the derived values for a Huffman table.
// This routine also performs some validation checks on the table.
static void jpeg_make_d_derived_tbl(jpeg_decompress cinfo, bool isDC, int tblno, ref d_derived_tbl pdtbl)
{
// Note that huffsize[] and huffcode[] are filled in code-length order,
// paralleling the order of the symbols themselves in htbl.huffval[].
// Find the input Huffman table
if (tblno < 0 || tblno >= NUM_HUFF_TBLS)
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tblno);
}
JHUFF_TBL htbl = isDC?cinfo.dc_huff_tbl_ptrs[tblno]:cinfo.ac_huff_tbl_ptrs[tblno];
if (htbl == null)
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tblno);
}
// Allocate a workspace if we haven't already done so.
if (pdtbl == null)
{
try
{
pdtbl = new d_derived_tbl();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
d_derived_tbl dtbl = pdtbl;
dtbl.pub = htbl; // fill in back link
// Figure C.1: make table of Huffman code length for each symbol
byte[] huffsize = new byte[257];
int p = 0;
for (byte l = 1; l <= 16; l++)
{
int i = (int)htbl.bits[l];
if (i < 0 || p + i > 256)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE); // protect against table overrun
}
while ((i--) != 0)
{
huffsize[p++] = l;
}
}
huffsize[p] = 0;
int numsymbols = p;
// Figure C.2: generate the codes themselves
// We also validate that the counts represent a legal Huffman code tree.
uint[] huffcode = new uint[257];
uint code = 0;
int si = huffsize[0];
p = 0;
while (huffsize[p] != 0)
{
while (((int)huffsize[p]) == si)
{
huffcode[p++] = code;
code++;
}
// code is now 1 more than the last code used for codelength si; but
// it must still fit in si bits, since no code is allowed to be all ones.
if (((int)code) >= (1 << si))
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE);
}
code <<= 1;
si++;
}
// Figure F.15: generate decoding tables for bit-sequential decoding
p = 0;
for (int l = 1; l <= 16; l++)
{
if (htbl.bits[l] != 0)
{
// valoffset[l] = huffval[] index of 1st symbol of code length l,
// minus the minimum code of length l
dtbl.valoffset[l] = (int)p - (int)huffcode[p];
p += htbl.bits[l];
dtbl.maxcode[l] = (int)huffcode[p - 1]; // maximum code of length l
}
else
{
dtbl.maxcode[l] = -1; // -1 if no codes of this length
}
}
dtbl.maxcode[17] = 0xFFFFF; // ensures jpeg_huff_decode terminates
// Compute lookahead tables to speed up decoding.
// First we set all the table entries to 0, indicating "too long";
// then we iterate through the Huffman codes that are short enough and
// fill in all the entries that correspond to bit sequences starting
// with that code.
for (int i = 0; i < dtbl.look_nbits.Length; i++)
{
dtbl.look_nbits[i] = 0;
}
p = 0;
for (int l = 1; l <= HUFF_LOOKAHEAD; l++)
{
for (int i = 1; i <= (int)htbl.bits[l]; i++, p++)
{
// l = current code's length, p = its index in huffcode[] & huffval[].
// Generate left-justified code followed by all possible bit sequences
int lookbits = ((int)huffcode[p]) << (HUFF_LOOKAHEAD - l);
for (int ctr = 1 << (HUFF_LOOKAHEAD - l); ctr > 0; ctr--)
{
dtbl.look_nbits[lookbits] = l;
dtbl.look_sym[lookbits] = htbl.huffval[p];
lookbits++;
}
}
}
// Validate symbols as being reasonable.
// For AC tables, we make no check, but accept all byte values 0..255.
// For DC tables, we require the symbols to be in range 0..16.
// (Tighter bounds could be applied depending on the data depth and mode,
// but this is sufficient to ensure safe decoding.)
if (isDC)
{
for (int i = 0; i < numsymbols; i++)
{
int sym = htbl.huffval[i];
if (sym < 0 || sym > 16)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_HUFF_TABLE);
}
}
}
}
// Decode and return nMCU's worth of Huffman-compressed differences.
// Each MCU is also disassembled and placed accordingly in diff_buf.
//
// MCU_col_num specifies the column of the first MCU being requested within
// the MCU-row. This tells us where to position the output row pointers in
// diff_buf.
//
// Returns the number of MCUs decoded. This may be less than nMCU if data
// source requested suspension. In that case no changes have been made to
// permanent state. (Exception: some output differences may already have
// been assigned. This is harmless for this module, since we'll just
// re-assign them on the next call.)
static uint decode_mcus_dlhuff(jpeg_decompress cinfo, int[][][] diff_buf, uint MCU_row_num, uint MCU_col_num, uint nMCU)
{
jpeg_lossless_d_codec losslsd = (jpeg_lossless_d_codec)cinfo.coef;
lhuff_entropy_decoder entropy = (lhuff_entropy_decoder)losslsd.entropy_private;
// Set output pointer locations based on MCU_col_num
for (int ptrn = 0; ptrn < entropy.num_output_ptrs; ptrn++)
{
int ci = entropy.output_ptr_info[ptrn].ci;
int yoffset = entropy.output_ptr_info[ptrn].yoffset;
int MCU_width = entropy.output_ptr_info[ptrn].MCU_width;
entropy.output_ptr[ptrn] = diff_buf[ci][MCU_row_num + yoffset];
entropy.output_ptr_ind[ptrn] = (int)(MCU_col_num * MCU_width);
}
// If we've run out of data, zero out the buffers and return.
// By resetting the undifferencer, the output samples will be CENTERJSAMPLE.
//
// NB: We should find a way to do this without interacting with the
// undifferencer module directly.
if (entropy.insufficient_data)
{
for (int ptrn = 0; ptrn < entropy.num_output_ptrs; ptrn++)
{
for (int i = 0; i < nMCU * entropy.output_ptr_info[ptrn].MCU_width; i++)
{
entropy.output_ptr[ptrn][entropy.output_ptr_ind[ptrn] + i] = 0;
}
}
losslsd.predict_process_restart(cinfo);
}
else
{
// Load up working state
//was BITREAD_STATE_VARS;
bitread_working_state br_state = new bitread_working_state();
//was BITREAD_LOAD_STATE(cinfo, entropy.bitstate);
br_state.cinfo = cinfo;
br_state.input_bytes = cinfo.src.input_bytes;
br_state.next_input_byte = cinfo.src.next_input_byte;
br_state.bytes_in_buffer = cinfo.src.bytes_in_buffer;
ulong get_buffer = entropy.bitstate.get_buffer;
int bits_left = entropy.bitstate.bits_left;
// Outer loop handles the number of MCU requested
for (uint mcu_num = 0; mcu_num < nMCU; mcu_num++)
{
// Inner loop handles the samples in the MCU
for (int sampn = 0; sampn < cinfo.blocks_in_MCU; sampn++)
{
d_derived_tbl dctbl = entropy.cur_tbls[sampn];
int s = 0, r;
// Section H.2.2: decode the sample difference
//was HUFF_DECODE(s, br_state, dctbl, return mcu_num, label1);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(mcu_num);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, dctbl, nb)) < 0)
{
return(mcu_num);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = dctbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = dctbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, dctbl, nb)) < 0)
{
return(mcu_num);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
if (s != 0)
{
if (s == 16)
{
s = 32768; // special case: always output 32768
}
else
{ // normal case: fetch subsequent bits
//was CHECK_BIT_BUFFER(br_state, s, return mcu_num);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(mcu_num);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(s);
r = ((int)(get_buffer >> (bits_left -= s))) & ((1 << s) - 1);
//was s=HUFF_EXTEND(r, s);
s = (r < (1 << (s - 1))?r + (((-1) << s) + 1):r);
}
}
// Output the sample difference
int ind = entropy.output_ptr_index[sampn];
entropy.output_ptr[ind][entropy.output_ptr_ind[ind]++] = (int)s;
}
// Completed MCU, so update state
//was BITREAD_SAVE_STATE(cinfo, entropy.bitstate);
cinfo.src.input_bytes = br_state.input_bytes;
cinfo.src.next_input_byte = br_state.next_input_byte;
cinfo.src.bytes_in_buffer = br_state.bytes_in_buffer;
entropy.bitstate.get_buffer = get_buffer;
entropy.bitstate.bits_left = bits_left;
}
}
return(nMCU);
}
// Out-of-line code for Huffman code decoding.
static int jpeg_huff_decode(ref bitread_working_state state, ulong get_buffer, int bits_left, d_derived_tbl htbl, int min_bits)
{
int l = min_bits;
// HUFF_DECODE has determined that the code is at least min_bits
// bits long, so fetch that many bits in one swoop.
//was CHECK_BIT_BUFFER(*state, l, return -1);
if (bits_left < l)
{
if (!jpeg_fill_bit_buffer(ref state, get_buffer, bits_left, l))
{
return(-1);
}
get_buffer = state.get_buffer;
bits_left = state.bits_left;
}
//was code = GET_BITS(l);
int code = ((int)(get_buffer >> (bits_left -= l))) & ((1 << l) - 1);
// Collect the rest of the Huffman code one bit at a time.
// This is per Figure F.16 in the JPEG spec.
while (code > htbl.maxcode[l])
{
code <<= 1;
//was CHECK_BIT_BUFFER(*state, 1, return -1);
if (bits_left < 1)
{
if (!jpeg_fill_bit_buffer(ref state, get_buffer, bits_left, 1))
{
return(-1);
}
get_buffer = state.get_buffer;
bits_left = state.bits_left;
}
//was code |= GET_BITS(1);
code |= ((int)(get_buffer >> (bits_left -= 1))) & 1;
l++;
}
// Unload the local registers
state.get_buffer = get_buffer;
state.bits_left = bits_left;
// With garbage input we may reach the sentinel value l = 17.
if (l > 16)
{
WARNMS(state.cinfo, J_MESSAGE_CODE.JWRN_HUFF_BAD_CODE);
return(0); // fake a zero as the safest result
}
return(htbl.pub.huffval[(int)(code + htbl.valoffset[l])]);
}
// Decode and return one MCU's worth of Huffman-compressed coefficients.
// The coefficients are reordered from zigzag order into natural array order,
// but are not dequantized.
//
// The i'th block of the MCU is stored into the block pointed to by
// MCU_data[i]. WE ASSUME THIS AREA HAS BEEN ZEROED BY THE CALLER.
// (Wholesale zeroing is usually a little faster than retail...)
//
// Returns false if data source requested suspension. In that case no
// changes have been made to permanent state. (Exception: some output
// coefficients may already have been assigned. This is harmless for
// this module, since we'll just re-assign them on the next call.)
static bool decode_mcu(jpeg_decompress cinfo, short[][] MCU_data)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
shuff_entropy_decoder entropy = (shuff_entropy_decoder)lossyd.entropy_private;
// Process restart marker if needed; may have to suspend
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
if (!process_restart_dshuff(cinfo))
{
return(false);
}
}
}
// If we've run out of data, just leave the MCU set to zeroes.
// This way, we return uniform gray for the remainder of the segment.
if (!entropy.insufficient_data)
{
bitread_working_state br_state = new bitread_working_state();
savable_state_sq state;
state.last_dc_val = new int[MAX_COMPS_IN_SCAN];
// Load up working state
//was BITREAD_STATE_VARS;
//was BITREAD_LOAD_STATE(cinfo, entropy.bitstate);
br_state.cinfo = cinfo;
br_state.input_bytes = cinfo.src.input_bytes;
br_state.next_input_byte = cinfo.src.next_input_byte;
br_state.bytes_in_buffer = cinfo.src.bytes_in_buffer;
ulong get_buffer = entropy.bitstate.get_buffer;
int bits_left = entropy.bitstate.bits_left;
//was state=entropy.saved;
entropy.saved.last_dc_val.CopyTo(state.last_dc_val, 0);
// Outer loop handles each block in the MCU
for (int blkn = 0; blkn < cinfo.blocks_in_MCU; blkn++)
{
short[] block = MCU_data[blkn];
d_derived_tbl dctbl = entropy.dc_cur_tbls[blkn];
d_derived_tbl actbl = entropy.ac_cur_tbls[blkn];
int s = 0, k, r;
// Decode a single block's worth of coefficients
// Section F.2.2.1: decode the DC coefficient difference
//was HUFF_DECODE(s, br_state, dctbl, return false, label1);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, dctbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = dctbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = dctbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, dctbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
if (s != 0)
{
//was CHECK_BIT_BUFFER(br_state, s, return false);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(s);
r = ((int)(get_buffer >> (bits_left -= s))) & ((1 << s) - 1);
//was s=HUFF_EXTEND(r, s);
s = (r < (1 << (s - 1))?r + (((-1) << s) + 1):r);
}
if (entropy.dc_needed[blkn])
{
// Convert DC difference to actual value, update last_dc_val
int ci = cinfo.MCU_membership[blkn];
s += state.last_dc_val[ci];
state.last_dc_val[ci] = s;
// Output the DC coefficient (assumes jpeg_natural_order[0] = 0)
block[0] = (short)s;
}
if (entropy.ac_needed[blkn])
{
// Section F.2.2.2: decode the AC coefficients
// Since zeroes are skipped, output area must be cleared beforehand
for (k = 1; k < DCTSIZE2; k++)
{
//was HUFF_DECODE(s, br_state, actbl, return false, label2);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, actbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = actbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = actbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, actbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
//was CHECK_BIT_BUFFER(br_state, s, return false);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(s);
r = ((int)(get_buffer >> (bits_left -= s))) & ((1 << s) - 1);
//was s=HUFF_EXTEND(r, s);
s = (r < (1 << (s - 1))?r + (((-1) << s) + 1):r);
// Output coefficient in natural (dezigzagged) order.
// Note: the extra entries in jpeg_natural_order[] will save us
// if k >= DCTSIZE2, which could happen if the data is corrupted.
block[jpeg_natural_order[k]] = (short)s;
}
else
{
if (r != 15)
{
break;
}
k += 15;
}
}
}
else
{
// Section F.2.2.2: decode the AC coefficients
// In this path we just discard the values
for (k = 1; k < DCTSIZE2; k++)
{
//was HUFF_DECODE(s, br_state, actbl, return false, label3);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, actbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = actbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = actbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, actbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
//was CHECK_BIT_BUFFER(br_state, s, return false);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was DROP_BITS(s);
bits_left -= s;
}
else
{
if (r != 15)
{
break;
}
k += 15;
}
}
}
}
// Completed MCU, so update state
//was BITREAD_SAVE_STATE(cinfo, entropy.bitstate);
cinfo.src.input_bytes = br_state.input_bytes;
cinfo.src.next_input_byte = br_state.next_input_byte;
cinfo.src.bytes_in_buffer = br_state.bytes_in_buffer;
entropy.bitstate.get_buffer = get_buffer;
entropy.bitstate.bits_left = bits_left;
//was entropy.saved=state;
state.last_dc_val.CopyTo(entropy.saved.last_dc_val, 0);
}
// Account for restart interval (no-op if not using restarts)
entropy.restarts_to_go--;
return(true);
}
// MCU decoding for AC successive approximation refinement scan.
static bool decode_mcu_AC_refine(jpeg_decompress cinfo, short[][] MCU_data)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
phuff_entropy_decoder entropy = (phuff_entropy_decoder)lossyd.entropy_private;
int Se = cinfo.Se;
short p1 = (short)(1 << cinfo.Al); // 1 in the bit position being coded
short m1 = (short)((-1) << cinfo.Al); // -1 in the bit position being coded
short[] block = null;
// If we are forced to suspend, we must undo the assignments to any newly
// nonzero coefficients in the block, because otherwise we'd get confused
// next time about which coefficients were already nonzero.
// But we need not undo addition of bits to already-nonzero coefficients;
// instead, we can test the current bit to see if we already did it.
int num_newnz = 0;
int[] newnz_pos = new int[DCTSIZE2];
// Process restart marker if needed; may have to suspend
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
if (!process_restart_dphuff(cinfo))
{
return(false);
}
}
}
// If we've run out of data, don't modify the MCU.
if (!entropy.insufficient_data)
{
// Load up working state
//was BITREAD_STATE_VARS;
bitread_working_state br_state = new bitread_working_state();
//was BITREAD_LOAD_STATE(cinfo, entropy.bitstate);
br_state.cinfo = cinfo;
br_state.input_bytes = cinfo.src.input_bytes;
br_state.next_input_byte = cinfo.src.next_input_byte;
br_state.bytes_in_buffer = cinfo.src.bytes_in_buffer;
ulong get_buffer = entropy.bitstate.get_buffer;
int bits_left = entropy.bitstate.bits_left;
uint EOBRUN = entropy.saved.EOBRUN; // only part of saved state we need
// There is always only one block per MCU
block = MCU_data[0];
d_derived_tbl tbl = entropy.ac_derived_tbl;
// initialize coefficient loop counter to start of band
int k = cinfo.Ss;
if (EOBRUN == 0)
{
for (; k <= Se; k++)
{
int s = 0, r;
//was HUFF_DECODE(s, br_state, tbl, goto undoit, label3);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
goto undoit;
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
goto undoit;
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = tbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = tbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
goto undoit;
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
r = s >> 4;
s &= 15;
if (s != 0)
{
if (s != 1)
{
WARNMS(cinfo, J_MESSAGE_CODE.JWRN_HUFF_BAD_CODE); // size of new coef should always be 1
}
//was CHECK_BIT_BUFFER(br_state, 1, goto undoit);
if (bits_left < 1)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 1))
{
goto undoit;
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was if (GET_BITS(1))
if ((((int)(get_buffer >> (bits_left -= 1))) & 1) != 0)
{
s = p1; // newly nonzero coef is positive
}
else
{
s = m1; // newly nonzero coef is negative
}
}
else
{
if (r != 15)
{
EOBRUN = (uint)(1 << r); // EOBr, run length is 2^r + appended bits
if (r != 0)
{
//was CHECK_BIT_BUFFER(br_state, r, goto undoit);
if (bits_left < r)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, r))
{
goto undoit;
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(r);
r = ((int)(get_buffer >> (bits_left -= r))) & ((1 << r) - 1);
EOBRUN += (uint)r;
}
break; // rest of block is handled by EOB logic
}
// note s = 0 for processing ZRL
}
// Advance over already-nonzero coefs and r still-zero coefs,
// appending correction bits to the nonzeroes. A correction bit is 1
// if the absolute value of the coefficient must be increased.
do
{
int thiscoef = jpeg_natural_order[k];
if (block[thiscoef] != 0)
{
//was CHECK_BIT_BUFFER(br_state, 1, goto undoit);
if (bits_left < 1)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 1))
{
goto undoit;
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was if (GET_BITS(1))
if ((((int)(get_buffer >> (bits_left -= 1))) & 1) != 0)
{
if ((block[thiscoef] & p1) == 0)
{ // do nothing if already set it
if (block[thiscoef] >= 0)
{
block[thiscoef] += p1;
}
else
{
block[thiscoef] += m1;
}
}
}
}
else
{
if (--r < 0)
{
break; // reached target zero coefficient
}
}
k++;
} while(k <= Se);
if (s != 0)
{
int pos = jpeg_natural_order[k];
// Output newly nonzero coefficient
block[pos] = (short)s;
// Remember its position in case we have to suspend
newnz_pos[num_newnz++] = pos;
}
}
}
if (EOBRUN > 0)
{
// Scan any remaining coefficient positions after the end-of-band
// (the last newly nonzero coefficient, if any). Append a correction
// bit to each already-nonzero coefficient. A correction bit is 1
// if the absolute value of the coefficient must be increased.
for (; k <= Se; k++)
{
int thiscoef = jpeg_natural_order[k];
if (block[thiscoef] != 0)
{
//was CHECK_BIT_BUFFER(br_state, 1, goto undoit);
if (bits_left < 1)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 1))
{
goto undoit;
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was if (GET_BITS(1))
if ((((int)(get_buffer >> (bits_left -= 1))) & 1) != 0)
{
if ((block[thiscoef] & p1) == 0)
{ // do nothing if already changed it
if (block[thiscoef] >= 0)
{
block[thiscoef] += p1;
}
else
{
block[thiscoef] += m1;
}
}
}
}
}
// Count one block completed in EOB run
EOBRUN--;
}
// Completed MCU, so update state
//was BITREAD_SAVE_STATE(cinfo, entropy.bitstate);
cinfo.src.input_bytes = br_state.input_bytes;
cinfo.src.next_input_byte = br_state.next_input_byte;
cinfo.src.bytes_in_buffer = br_state.bytes_in_buffer;
entropy.bitstate.get_buffer = get_buffer;
entropy.bitstate.bits_left = bits_left;
entropy.saved.EOBRUN = EOBRUN; // only part of saved state we need
}
// Account for restart interval (no-op if not using restarts)
entropy.restarts_to_go--;
return(true);
undoit:
// Re-zero any output coefficients that we made newly nonzero
while (num_newnz > 0)
{
block[newnz_pos[--num_newnz]] = 0;
}
return(false);
}
// MCU decoding for AC initial scan (either spectral selection,
// or first pass of successive approximation).
static bool decode_mcu_AC_first(jpeg_decompress cinfo, short[][] MCU_data)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
phuff_entropy_decoder entropy = (phuff_entropy_decoder)lossyd.entropy_private;
int Se = cinfo.Se;
int Al = cinfo.Al;
// Process restart marker if needed; may have to suspend
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
if (!process_restart_dphuff(cinfo))
{
return(false);
}
}
}
// If we've run out of data, just leave the MCU set to zeroes.
// This way, we return uniform gray for the remainder of the segment.
if (!entropy.insufficient_data)
{
// Load up working state.
// We can avoid loading/saving bitread state if in an EOB run.
uint EOBRUN = entropy.saved.EOBRUN; // only part of saved state we need
// There is always only one block per MCU
if (EOBRUN > 0)
{
EOBRUN--; // if it's a band of zeroes... ...process it now (we do nothing)
}
else
{
//was BITREAD_STATE_VARS;
bitread_working_state br_state = new bitread_working_state();
//was BITREAD_LOAD_STATE(cinfo, entropy.bitstate);
br_state.cinfo = cinfo;
br_state.input_bytes = cinfo.src.input_bytes;
br_state.next_input_byte = cinfo.src.next_input_byte;
br_state.bytes_in_buffer = cinfo.src.bytes_in_buffer;
ulong get_buffer = entropy.bitstate.get_buffer;
int bits_left = entropy.bitstate.bits_left;
short[] block = MCU_data[0];
d_derived_tbl tbl = entropy.ac_derived_tbl;
for (int k = cinfo.Ss; k <= Se; k++)
{
int s = 0, r;
//was HUFF_DECODE(s, br_state, tbl, return false, label2);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = tbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = tbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
r = s >> 4;
s &= 15;
if (s != 0)
{
k += r;
//was CHECK_BIT_BUFFER(br_state, s, return false);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(s);
r = ((int)(get_buffer >> (bits_left -= s))) & ((1 << s) - 1);
//was s=HUFF_EXTEND(r, s);
s = (r < (1 << (s - 1))?r + (((-1) << s) + 1):r);
// Scale and output coefficient in natural (dezigzagged) order
block[jpeg_natural_order[k]] = (short)(s << Al);
}
else
{
if (r == 15)
{ // ZRL
k += 15; // skip 15 zeroes in band
}
else
{ // EOBr, run length is 2^r + appended bits
EOBRUN = (uint)(1 << r);
if (r != 0)
{ // EOBr, r > 0
//was CHECK_BIT_BUFFER(br_state, r, return false);
if (bits_left < r)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, r))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(r);
r = ((int)(get_buffer >> (bits_left -= r))) & ((1 << r) - 1);
EOBRUN += (uint)r;
}
EOBRUN--; // this band is processed at this moment
break; // force end-of-band
}
}
}
//was BITREAD_SAVE_STATE(cinfo, entropy.bitstate);
cinfo.src.input_bytes = br_state.input_bytes;
cinfo.src.next_input_byte = br_state.next_input_byte;
cinfo.src.bytes_in_buffer = br_state.bytes_in_buffer;
entropy.bitstate.get_buffer = get_buffer;
entropy.bitstate.bits_left = bits_left;
}
// Completed MCU, so update state
entropy.saved.EOBRUN = EOBRUN; // only part of saved state we need
}
// Account for restart interval (no-op if not using restarts)
entropy.restarts_to_go--;
return(true);
}
// Huffman MCU decoding.
// Each of these routines decodes and returns one MCU's worth of
// Huffman-compressed coefficients.
// The coefficients are reordered from zigzag order into natural array order,
// but are not dequantized.
//
// The i'th block of the MCU is stored into the block pointed to by
// MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER.
//
// We return false if data source requested suspension. In that case no
// changes have been made to permanent state. (Exception: some output
// coefficients may already have been assigned. This is harmless for
// spectral selection, since we'll just re-assign them on the next call.
// Successive approximation AC refinement has to be more careful, however.)
// MCU decoding for DC initial scan (either spectral selection,
// or first pass of successive approximation).
static bool decode_mcu_DC_first(jpeg_decompress cinfo, short[][] MCU_data)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
phuff_entropy_decoder entropy = (phuff_entropy_decoder)lossyd.entropy_private;
int Al = cinfo.Al;
// Process restart marker if needed; may have to suspend
if (cinfo.restart_interval != 0)
{
if (entropy.restarts_to_go == 0)
{
if (!process_restart_dphuff(cinfo))
{
return(false);
}
}
}
// If we've run out of data, just leave the MCU set to zeroes.
// This way, we return uniform gray for the remainder of the segment.
if (!entropy.insufficient_data)
{
// Load up working state
//was BITREAD_STATE_VARS;
bitread_working_state br_state = new bitread_working_state();
savable_state state;
state.last_dc_val = new int[MAX_COMPS_IN_SCAN];
//was BITREAD_LOAD_STATE(cinfo, entropy.bitstate);
br_state.cinfo = cinfo;
br_state.input_bytes = cinfo.src.input_bytes;
br_state.next_input_byte = cinfo.src.next_input_byte;
br_state.bytes_in_buffer = cinfo.src.bytes_in_buffer;
ulong get_buffer = entropy.bitstate.get_buffer;
int bits_left = entropy.bitstate.bits_left;
//was state=entropy.saved;
state.EOBRUN = entropy.saved.EOBRUN;
entropy.saved.last_dc_val.CopyTo(state.last_dc_val, 0);
// Outer loop handles each block in the MCU
for (int blkn = 0; blkn < cinfo.blocks_in_MCU; blkn++)
{
short[] block = MCU_data[blkn];
int ci = cinfo.MCU_membership[blkn];
jpeg_component_info compptr = cinfo.cur_comp_info[ci];
d_derived_tbl tbl = entropy.derived_tbls[compptr.dc_tbl_no];
int s = 0;
// Decode a single block's worth of coefficients
// Section F.2.2.1: decode the DC coefficient difference
//was HUFF_DECODE(s, br_state, tbl, return false, label1);
{
int nb, look;
bool label = false;
if (bits_left < HUFF_LOOKAHEAD)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, 0))
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
if (bits_left < HUFF_LOOKAHEAD)
{
nb = 1;
label = true;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
if (!label)
{
//was look=PEEK_BITS(HUFF_LOOKAHEAD);
look = ((int)(get_buffer >> (bits_left - HUFF_LOOKAHEAD))) & ((1 << HUFF_LOOKAHEAD) - 1);
if ((nb = tbl.look_nbits[look]) != 0)
{
//was DROP_BITS(nb);
bits_left -= nb;
s = tbl.look_sym[look];
}
else
{
nb = HUFF_LOOKAHEAD + 1;
if ((s = jpeg_huff_decode(ref br_state, get_buffer, bits_left, tbl, nb)) < 0)
{
return(false);
}
get_buffer = br_state.get_buffer;
bits_left = br_state.bits_left;
}
}
}
if (s != 0)
{
//was CHECK_BIT_BUFFER(br_state, s, return false);
if (bits_left < s)
{
if (!jpeg_fill_bit_buffer(ref br_state, get_buffer, bits_left, s))
{
return(false);
}
get_buffer = br_state.get_buffer; bits_left = br_state.bits_left;
}
//was r = GET_BITS(s);
int r = ((int)(get_buffer >> (bits_left -= s))) & ((1 << s) - 1);
//was s=HUFF_EXTEND(r, s);
s = (r < (1 << (s - 1))?r + (((-1) << s) + 1):r);
}
// Convert DC difference to actual value, update last_dc_val
s += state.last_dc_val[ci];
state.last_dc_val[ci] = s;
// Scale and output the coefficient (assumes jpeg_natural_order[0]=0)
block[0] = (short)(s << Al);
}
// Completed MCU, so update state
//was BITREAD_SAVE_STATE(cinfo, entropy.bitstate);
cinfo.src.input_bytes = br_state.input_bytes;
cinfo.src.next_input_byte = br_state.next_input_byte;
cinfo.src.bytes_in_buffer = br_state.bytes_in_buffer;
entropy.bitstate.get_buffer = get_buffer;
entropy.bitstate.bits_left = bits_left;
//was entropy.saved=state;
entropy.saved.EOBRUN = state.EOBRUN;
state.last_dc_val.CopyTo(entropy.saved.last_dc_val, 0);
}
// Account for restart interval (no-op if not using restarts)
entropy.restarts_to_go--;
return(true);
}
