// Emit a restart marker & resynchronize predictions.
static bool emit_restart(ref working_state_sq state, int restart_num)
{
if (!flush_bits(ref state))
{
return(false);
}
//was emit_byte(state, 0xFF, return false);
state.output_bytes[state.next_output_byte++] = 0xFF;
state.free_in_buffer--;
if (state.free_in_buffer == 0)
{
if (!dump_buffer(ref state))
{
return(false);
}
}
//was emit_byte(state, JPEG_RST0 + restart_num, return false);
state.output_bytes[state.next_output_byte++] = (byte)(JPEG_RST0 + restart_num);
state.free_in_buffer--;
if (state.free_in_buffer == 0)
{
if (!dump_buffer(ref state))
{
return(false);
}
}
// Re-initialize DC predictions to 0
for (int ci = 0; ci < state.cinfo.comps_in_scan; ci++)
{
state.cur.last_dc_val[ci] = 0;
}
// The restart counter is not updated until we successfully write the MCU.
return(true);
}
// Emit a restart marker & resynchronize predictions.
static bool emit_restart(ref working_state_sq state, int restart_num)
{
if(!flush_bits(ref state)) return false;
//was emit_byte(state, 0xFF, return false);
state.output_bytes[state.next_output_byte++]=0xFF;
state.free_in_buffer--;
if(state.free_in_buffer==0)
{
if(!dump_buffer(ref state)) return false;
}
//was emit_byte(state, JPEG_RST0 + restart_num, return false);
state.output_bytes[state.next_output_byte++]=(byte)(JPEG_RST0+restart_num);
state.free_in_buffer--;
if(state.free_in_buffer==0)
{
if(!dump_buffer(ref state)) return false;
}
// Re-initialize DC predictions to 0
for(int ci=0; ci<state.cinfo.comps_in_scan; ci++) state.cur.last_dc_val[ci]=0;
// The restart counter is not updated until we successfully write the MCU.
return true;
}
// Encode a single block's worth of coefficients
static bool encode_one_block(ref working_state_sq state, short[] block, int last_dc_val, c_derived_tbl dctbl, c_derived_tbl actbl)
{
// Encode the DC coefficient difference per section F.1.2.1
int temp=block[0]-last_dc_val;
int temp2=temp;
if(temp<0)
{
temp=-temp; // temp is abs value of input
// For a negative input, want temp2 = bitwise complement of abs(input)
// This code assumes we are on a two's complement machine
temp2--;
}
// Find the number of bits needed for the magnitude of the coefficient
int nbits=0;
while(temp!=0)
{
nbits++;
temp>>=1;
}
// Check for out-of-range coefficient values.
// Since we're encoding a difference, the range limit is twice as much.
if(nbits>MAX_COEF_BITS+1) ERREXIT(state.cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
// Emit the Huffman-coded symbol for the number of bits
if(!emit_bits(ref state, dctbl.ehufco[nbits], dctbl.ehufsi[nbits])) return false;
// 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
{
if(!emit_bits(ref state, (uint)temp2, nbits)) return false;
}
// Encode the AC coefficients per section F.1.2.2
int r=0; // r = run length of zeros
for(int k=1; k<DCTSIZE2; k++)
{
temp=block[jpeg_natural_order[k]];
if(temp==0)
{
r++;
continue;
}
// if run length > 15, must emit special run-length-16 codes (0xF0)
while(r>15)
{
if(!emit_bits(ref state, actbl.ehufco[0xF0], actbl.ehufsi[0xF0])) return false;
r-=16;
}
temp2=temp;
if(temp<0)
{
temp=-temp; // temp is abs value of input
// This code assumes we are on a two's complement machine
temp2--;
}
// Find the number of bits needed for the magnitude of the coefficient
nbits=1; // there must be at least one 1 bit
while((temp>>=1)!=0) nbits++;
// Check for out-of-range coefficient values
if(nbits>MAX_COEF_BITS) ERREXIT(state.cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
// Emit Huffman symbol for run length / number of bits
int i=(r<<4)+nbits;
if(!emit_bits(ref state, actbl.ehufco[i], actbl.ehufsi[i])) return false;
// Emit that number of bits of the value, if positive,
// or the complement of its magnitude, if negative.
if(!emit_bits(ref state, (uint)temp2, nbits)) return false;
r=0;
}
// If the last coef(s) were zero, emit an end-of-block code
if(r>0)
{
if(!emit_bits(ref state, actbl.ehufco[0], actbl.ehufsi[0])) return false;
}
return true;
}
static bool flush_bits(ref working_state_sq state)
{
if(!emit_bits(ref state, 0x7F, 7)) return false; // fill any partial byte with ones
state.cur.put_buffer=0; // and reset bit-buffer to empty
state.cur.put_bits=0;
return true;
}
// Outputting bits to the file
// Only the right 24 bits of put_buffer are used; the valid bits are
// left-justified in this part. At most 16 bits can be passed to emit_bits
// in one call, and we never retain more than 7 bits in put_buffer
// between calls, so 24 bits are sufficient.
// Emit some bits; return true if successful, false if must suspend
static bool emit_bits(ref working_state_sq state, uint code, int size)
{
// This routine is heavily used, so it's worth coding tightly.
int put_buffer=(int)code;
int put_bits=state.cur.put_bits;
// if size is 0, caller used an invalid Huffman table entry
if(size==0) ERREXIT(state.cinfo, J_MESSAGE_CODE.JERR_HUFF_MISSING_CODE);
put_buffer&=(1<<size)-1; // mask off any extra bits in code
put_bits+=size; // new number of bits in buffer
put_buffer<<=24-put_bits; // align incoming bits
put_buffer|=state.cur.put_buffer; // and merge with old buffer contents
while(put_bits>=8)
{
byte c=(byte)((put_buffer>>16)&0xFF);
//was emit_byte(state, c, return false);
state.output_bytes[state.next_output_byte++]=c;
state.free_in_buffer--;
if(state.free_in_buffer==0)
{
if(!dump_buffer(ref state)) return false;
}
if(c==0xFF)
{ // need to stuff a zero byte?
//was emit_byte(state, 0, return false);
state.output_bytes[state.next_output_byte++]=0;
state.free_in_buffer--;
if(state.free_in_buffer==0)
{
if(!dump_buffer(ref state)) return false;
}
}
put_buffer<<=8;
put_bits-=8;
}
state.cur.put_buffer=put_buffer; // update state variables
state.cur.put_bits=put_bits;
return true;
}
// Outputting bytes to the file
// Empty the output buffer; return true if successful, false if must suspend
static bool dump_buffer(ref working_state_sq state)
{
jpeg_destination_mgr dest=state.cinfo.dest;
if(!dest.empty_output_buffer(state.cinfo)) return false;
// After a successful buffer dump, must reset buffer pointers
state.output_bytes=dest.output_bytes;
state.next_output_byte=dest.next_output_byte;
state.free_in_buffer=dest.free_in_buffer;
return true;
}
// Encode a single block's worth of coefficients
static bool encode_one_block(ref working_state_sq state, short[] block, int last_dc_val, c_derived_tbl dctbl, c_derived_tbl actbl)
{
// Encode the DC coefficient difference per section F.1.2.1
int temp = block[0] - last_dc_val;
int temp2 = temp;
if (temp < 0)
{
temp = -temp; // temp is abs value of input
// For a negative input, want temp2 = bitwise complement of abs(input)
// This code assumes we are on a two's complement machine
temp2--;
}
// Find the number of bits needed for the magnitude of the coefficient
int nbits = 0;
while (temp != 0)
{
nbits++;
temp >>= 1;
}
// Check for out-of-range coefficient values.
// Since we're encoding a difference, the range limit is twice as much.
if (nbits > MAX_COEF_BITS + 1)
{
ERREXIT(state.cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
}
// Emit the Huffman-coded symbol for the number of bits
if (!emit_bits(ref state, dctbl.ehufco[nbits], dctbl.ehufsi[nbits]))
{
return(false);
}
// 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
{
if (!emit_bits(ref state, (uint)temp2, nbits))
{
return(false);
}
}
// Encode the AC coefficients per section F.1.2.2
int r = 0; // r = run length of zeros
for (int k = 1; k < DCTSIZE2; k++)
{
temp = block[jpeg_natural_order[k]];
if (temp == 0)
{
r++;
continue;
}
// if run length > 15, must emit special run-length-16 codes (0xF0)
while (r > 15)
{
if (!emit_bits(ref state, actbl.ehufco[0xF0], actbl.ehufsi[0xF0]))
{
return(false);
}
r -= 16;
}
temp2 = temp;
if (temp < 0)
{
temp = -temp; // temp is abs value of input
// This code assumes we are on a two's complement machine
temp2--;
}
// Find the number of bits needed for the magnitude of the coefficient
nbits = 1; // there must be at least one 1 bit
while ((temp >>= 1) != 0)
{
nbits++;
}
// Check for out-of-range coefficient values
if (nbits > MAX_COEF_BITS)
{
ERREXIT(state.cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
}
// Emit Huffman symbol for run length / number of bits
int i = (r << 4) + nbits;
if (!emit_bits(ref state, actbl.ehufco[i], actbl.ehufsi[i]))
{
return(false);
}
// Emit that number of bits of the value, if positive,
// or the complement of its magnitude, if negative.
if (!emit_bits(ref state, (uint)temp2, nbits))
{
return(false);
}
r = 0;
}
// If the last coef(s) were zero, emit an end-of-block code
if (r > 0)
{
if (!emit_bits(ref state, actbl.ehufco[0], actbl.ehufsi[0]))
{
return(false);
}
}
return(true);
}
