//  * jcmarker.c
//  *
//  * Copyright (C) 1991-1995, Thomas G. Lane.
//  * This file is part of the Independent JPEG Group's software.
//  * For conditions of distribution and use, see the accompanying README file.
//  *
//  * This file contains routines to write JPEG datastream markers.



#define JPEG_INTERNALS
#include "JINCLUDE.h"
#include "JPEGLIB.h"


typedef enum {			// JPEG marker codes 
  M_SOF0  = 0xc0,
  M_SOF1  = 0xc1,
  M_SOF2  = 0xc2,
  M_SOF3  = 0xc3,

  M_SOF5  = 0xc5,
  M_SOF6  = 0xc6,
  M_SOF7  = 0xc7,

  M_JPG   = 0xc8,
  M_SOF9  = 0xc9,
  M_SOF10 = 0xca,
  M_SOF11 = 0xcb,

  M_SOF13 = 0xcd,
  M_SOF14 = 0xce,
  M_SOF15 = 0xcf,

  M_DHT   = 0xc4,

  M_DAC   = 0xcc,

  M_RST0  = 0xd0,
  M_RST1  = 0xd1,
  M_RST2  = 0xd2,
  M_RST3  = 0xd3,
  M_RST4  = 0xd4,
  M_RST5  = 0xd5,
  M_RST6  = 0xd6,
  M_RST7  = 0xd7,

  M_SOI   = 0xd8,
  M_EOI   = 0xd9,
  M_SOS   = 0xda,
  M_DQT   = 0xdb,
  M_DNL   = 0xdc,
  M_DRI   = 0xdd,
  M_DHP   = 0xde,
  M_EXP   = 0xdf,

  M_APP0  = 0xe0,
  M_APP1  = 0xe1,
  M_APP2  = 0xe2,
  M_APP3  = 0xe3,
  M_APP4  = 0xe4,
  M_APP5  = 0xe5,
  M_APP6  = 0xe6,
  M_APP7  = 0xe7,
  M_APP8  = 0xe8,
  M_APP9  = 0xe9,
  M_APP10 = 0xea,
  M_APP11 = 0xeb,
  M_APP12 = 0xec,
  M_APP13 = 0xed,
  M_APP14 = 0xee,
  M_APP15 = 0xef,

  M_JPG0  = 0xf0,
  M_JPG13 = 0xfd,
  M_COM   = 0xfe,

  M_TEM   = 0x01,

  M_ERROR = 0x100
} JPEG_MARKER;


//  * Basic output routines.
//  *
//  * Note that we do not support suspension while writing a marker.
//  * Therefore, an application using suspension must ensure that there is
//  * enough buffer space for the initial markers (typ. 600-700 bytes) before
//  * calling jpeg_start_compress, and enough space to write the trailing EOI
//  * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
//  * modes are not supported at all with suspension, so those two are the only
//  * points where markers will be written.

LOCAL void
emit_byte (j_compress_ptr cinfo, int val)
// Emit a byte 
{
  struct jpeg_destination_mgr * dest = cinfo->dest;

  *(dest->next_output_byte)++ = (JOCTET) val;
  if (--dest->free_in_buffer == 0) {
    if (! (*dest->empty_output_buffer) (cinfo))
      ERREXIT(cinfo, JERR_CANT_SUSPEND);
  }
}


LOCAL void
emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
// Emit a marker code 
{
  emit_byte(cinfo, 0xFF);
  emit_byte(cinfo, (int) mark);
}


LOCAL void
emit_2bytes (j_compress_ptr cinfo, int value)
// Emit a 2-byte integer; these are always MSB first in JPEG files 
{
  emit_byte(cinfo, (value >> 8) & 0xFF);
  emit_byte(cinfo, value & 0xFF);
}


//  * Routines to write specific marker types.

LOCAL int
emit_dqt (j_compress_ptr cinfo, int index)
// Emit a DQT marker 
// Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking 
{
  JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
  int prec;
  int i;

  if (qtbl == NULL)
    ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);

  prec = 0;
  for (i = 0; i < DCTSIZE2; i++) {
    if (qtbl->quantval[i] > 255)
      prec = 1;
  }

  if (! qtbl->sent_table) {
    emit_marker(cinfo, M_DQT);

    emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);

    emit_byte(cinfo, index + (prec<<4));

    for (i = 0; i < DCTSIZE2; i++) {
      if (prec)
	emit_byte(cinfo, qtbl->quantval[i] >> 8);
      emit_byte(cinfo, qtbl->quantval[i] & 0xFF);
    }

    qtbl->sent_table = TRUE;
  }

  return prec;
}


LOCAL void
emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
// Emit a DHT marker 
{
  JHUFF_TBL * htbl;
  int length, i;

  if (is_ac) {
    htbl = cinfo->ac_huff_tbl_ptrs[index];
    index += 0x10;		// output index has AC bit set 
  } else {
    htbl = cinfo->dc_huff_tbl_ptrs[index];
  }

  if (htbl == NULL)
    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);

  if (! htbl->sent_table) {
    emit_marker(cinfo, M_DHT);

    length = 0;
    for (i = 1; i <= 16; i++)
      length += htbl->bits[i];

    emit_2bytes(cinfo, length + 2 + 1 + 16);
    emit_byte(cinfo, index);

    for (i = 1; i <= 16; i++)
      emit_byte(cinfo, htbl->bits[i]);

    for (i = 0; i < length; i++)
      emit_byte(cinfo, htbl->huffval[i]);

    htbl->sent_table = TRUE;
  }
}


LOCAL void
emit_dac (j_compress_ptr cinfo)
// Emit a DAC marker 
// Since the useful info is so small, we want to emit all the tables in 
// one DAC marker.  Therefore this routine does its own scan of the table. 
{
#ifdef C_ARITH_CODING_SUPPORTED
  char dc_in_use[NUM_ARITH_TBLS];
  char ac_in_use[NUM_ARITH_TBLS];
  int length, i;
  jpeg_component_info *compptr;

  for (i = 0; i < NUM_ARITH_TBLS; i++)
    dc_in_use[i] = ac_in_use[i] = 0;

  for (i = 0; i < cinfo->comps_in_scan; i++) {
    compptr = cinfo->cur_comp_info[i];
    dc_in_use[compptr->dc_tbl_no] = 1;
    ac_in_use[compptr->ac_tbl_no] = 1;
  }

  length = 0;
  for (i = 0; i < NUM_ARITH_TBLS; i++)
    length += dc_in_use[i] + ac_in_use[i];

  emit_marker(cinfo, M_DAC);

  emit_2bytes(cinfo, length*2 + 2);

  for (i = 0; i < NUM_ARITH_TBLS; i++) {
    if (dc_in_use[i]) {
      emit_byte(cinfo, i);
      emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
    }
    if (ac_in_use[i]) {
      emit_byte(cinfo, i + 0x10);
      emit_byte(cinfo, cinfo->arith_ac_K[i]);
    }
  }
#endif // C_ARITH_CODING_SUPPORTED 
}


LOCAL void
emit_dri (j_compress_ptr cinfo)
// Emit a DRI marker 
{
  emit_marker(cinfo, M_DRI);

  emit_2bytes(cinfo, 4);	// fixed length 

  emit_2bytes(cinfo, (int) cinfo->restart_interval);
}


LOCAL void
emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
// Emit a SOF marker 
{
  int ci;
  jpeg_component_info *compptr;

  emit_marker(cinfo, code);

  emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); // length 

  // Make sure image isn't bigger than SOF field can handle 
  if ((LONG) cinfo->image_height > 65535L ||
      (LONG) cinfo->image_width > 65535L)
    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);

  emit_byte(cinfo, cinfo->data_precision);
  emit_2bytes(cinfo, (int) cinfo->image_height);
  emit_2bytes(cinfo, (int) cinfo->image_width);

  emit_byte(cinfo, cinfo->num_components);

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    emit_byte(cinfo, compptr->component_id);
    emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
    emit_byte(cinfo, compptr->quant_tbl_no);
  }
}


LOCAL void
emit_sos (j_compress_ptr cinfo)
// Emit a SOS marker 
{
  int i, td, ta;
  jpeg_component_info *compptr;

  emit_marker(cinfo, M_SOS);

  emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); // length 

  emit_byte(cinfo, cinfo->comps_in_scan);

  for (i = 0; i < cinfo->comps_in_scan; i++) {
    compptr = cinfo->cur_comp_info[i];
    emit_byte(cinfo, compptr->component_id);
    td = compptr->dc_tbl_no;
    ta = compptr->ac_tbl_no;
    if (cinfo->progressive_mode) {
//  Progressive mode: only DC or only AC tables are used in one scan;
//        * furthermore, Huffman coding of DC refinement uses no table at all.
//        * We emit 0 for unused field(s); this is recommended by the P&M text
//        * but does not seem to be specified in the standard.
      if (cinfo->Ss == 0) {
	ta = 0;			// DC scan 
	if (cinfo->Ah != 0 && !cinfo->arith_code)
	  td = 0;		// no DC table either 
      } else {
	td = 0;			// AC scan 
      }
    }
    emit_byte(cinfo, (td << 4) + ta);
  }

  emit_byte(cinfo, cinfo->Ss);
  emit_byte(cinfo, cinfo->Se);
  emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
}


LOCAL void
emit_jfif_app0 (j_compress_ptr cinfo)
// Emit a JFIF-compliant APP0 marker 
{
//    * Length of APP0 block	(2 bytes)
//    * Block ID			(4 bytes - ASCII "JFIF")
//    * Zero byte			(1 byte to terminate the ID string)
//    * Version Major, Minor	(2 bytes - 0x01, 0x01)
//    * Units			(1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
//    * Xdpu			(2 bytes - dots per unit horizontal)
//    * Ydpu			(2 bytes - dots per unit vertical)
//    * Thumbnail X size		(1 byte)
//    * Thumbnail Y size		(1 byte)

  emit_marker(cinfo, M_APP0);

  emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); // length 

  emit_byte(cinfo, 0x4A);	// Identifier: ASCII "JFIF" 
  emit_byte(cinfo, 0x46);
  emit_byte(cinfo, 0x49);
  emit_byte(cinfo, 0x46);
  emit_byte(cinfo, 0);
//  We currently emit version code 1.01 since we use no 1.02 features.
//    * This may avoid complaints from some older decoders.
  emit_byte(cinfo, 1);		// Major version 
  emit_byte(cinfo, 1);		// Minor version 
  emit_byte(cinfo, cinfo->density_unit); // Pixel size information 
  emit_2bytes(cinfo, (int) cinfo->X_density);
  emit_2bytes(cinfo, (int) cinfo->Y_density);
  emit_byte(cinfo, 0);		// No thumbnail image 
  emit_byte(cinfo, 0);
}


LOCAL void
emit_adobe_app14 (j_compress_ptr cinfo)
// Emit an Adobe APP14 marker 
{
//    * Length of APP14 block	(2 bytes)
//    * Block ID			(5 bytes - ASCII "Adobe")
//    * Version Number		(2 bytes - currently 100)
//    * Flags0			(2 bytes - currently 0)
//    * Flags1			(2 bytes - currently 0)
//    * Color transform		(1 byte)
//    *
//    * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
//    * now in circulation seem to use Version = 100, so that's what we write.
//    *
//    * We write the color transform byte as 1 if the JPEG color space is
//    * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
//    * whether the encoder performed a transformation, which is pretty useless.

  emit_marker(cinfo, M_APP14);

  emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); // length 

  emit_byte(cinfo, 0x41);	// Identifier: ASCII "Adobe" 
  emit_byte(cinfo, 0x64);
  emit_byte(cinfo, 0x6F);
  emit_byte(cinfo, 0x62);
  emit_byte(cinfo, 0x65);
  emit_2bytes(cinfo, 100);	// Version 
  emit_2bytes(cinfo, 0);	// Flags0 
  emit_2bytes(cinfo, 0);	// Flags1 
  switch (cinfo->jpeg_color_space) {
  case JCS_YCbCr:
    emit_byte(cinfo, 1);	// Color transform = 1 
    break;
  case JCS_YCCK:
    emit_byte(cinfo, 2);	// Color transform = 2 
    break;
  default:
    emit_byte(cinfo, 0);	// Color transform = 0 
    break;
  }
}


//  * This routine is exported for possible use by applications.
//  * The intended use is to emit COM or APPn markers after calling
//  * jpeg_start_compress() and before the first jpeg_write_scanlines() call
//  * (hence, after write_file_header but before write_frame_header).
//  * Other uses are not guaranteed to produce desirable results.

METHODDEF void
write_any_marker (j_compress_ptr cinfo, int marker,
		  const JOCTET *dataptr, unsigned int datalen)
// Emit an arbitrary marker with parameters 
{
  if (datalen <= (unsigned int) 65533) { // safety check 
    emit_marker(cinfo, (JPEG_MARKER) marker);

    emit_2bytes(cinfo, (int) (datalen + 2)); // total length 

    while (datalen--) {
      emit_byte(cinfo, *dataptr);
      dataptr++;
    }
  }
}


//  * Write datastream header.
//  * This consists of an SOI and optional APPn markers.
//  * We recommend use of the JFIF marker, but not the Adobe marker,
//  * when using YCbCr or grayscale data.  The JFIF marker should NOT
//  * be used for any other JPEG colorspace.  The Adobe marker is helpful
//  * to distinguish RGB, CMYK, and YCCK colorspaces.
//  * Note that an application can write additional header markers after
//  * jpeg_start_compress returns.

METHODDEF void
write_file_header (j_compress_ptr cinfo)
{
  emit_marker(cinfo, M_SOI);	// first the SOI 

  if (cinfo->write_JFIF_header)	// next an optional JFIF APP0 
    emit_jfif_app0(cinfo);
  if (cinfo->write_Adobe_marker) // next an optional Adobe APP14 
    emit_adobe_app14(cinfo);
}


//  * Write frame header.
//  * This consists of DQT and SOFn markers.
//  * Note that we do not emit the SOF until we have emitted the DQT(s).
//  * This avoids compatibility problems with incorrect implementations that
//  * try to error-check the quant table numbers as soon as they see the SOF.

METHODDEF void
write_frame_header (j_compress_ptr cinfo)
{
  int ci, prec;
  boolean is_baseline;
  jpeg_component_info *compptr;

//  Emit DQT for each quantization table.
//    * Note that emit_dqt() suppresses any duplicate tables.
  prec = 0;
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    prec += emit_dqt(cinfo, compptr->quant_tbl_no);
  }
  // now prec is nonzero iff there are any 16-bit quant tables. 

//  Check for a non-baseline specification.
//    * Note we assume that Huffman table numbers won't be changed later.
  if (cinfo->arith_code || cinfo->progressive_mode ||
      cinfo->data_precision != 8) {
    is_baseline = FALSE;
  } else {
    is_baseline = TRUE;
    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
	 ci++, compptr++) {
      if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
	is_baseline = FALSE;
    }
    if (prec && is_baseline) {
      is_baseline = FALSE;
      // If it's baseline except for quantizer size, warn the user 
      TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
    }
  }

  // Emit the proper SOF marker 
  if (cinfo->arith_code) {
    emit_sof(cinfo, M_SOF9);	// SOF code for arithmetic coding 
  } else {
    if (cinfo->progressive_mode)
      emit_sof(cinfo, M_SOF2);	// SOF code for progressive Huffman 
    else if (is_baseline)
      emit_sof(cinfo, M_SOF0);	// SOF code for baseline implementation 
    else
      emit_sof(cinfo, M_SOF1);	// SOF code for non-baseline Huffman file 
  }
}


//  * Write scan header.
//  * This consists of DHT or DAC markers, optional DRI, and SOS.
//  * Compressed data will be written following the SOS.

METHODDEF void
write_scan_header (j_compress_ptr cinfo)
{
  int i;
  jpeg_component_info *compptr;

  if (cinfo->arith_code) {
//  Emit arith conditioning info.  We may have some duplication
//      * if the file has multiple scans, but it's so small it's hardly
//      * worth worrying about.
    emit_dac(cinfo);
  } else {
//  Emit Huffman tables.
//      * Note that emit_dht() suppresses any duplicate tables.
    for (i = 0; i < cinfo->comps_in_scan; i++) {
      compptr = cinfo->cur_comp_info[i];
      if (cinfo->progressive_mode) {
	// Progressive mode: only DC or only AC tables are used in one scan 
	if (cinfo->Ss == 0) {
	  if (cinfo->Ah == 0)	// DC needs no table for refinement scan 
	    emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
	} else {
	  emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
	}
      } else {
	// Sequential mode: need both DC and AC tables 
	emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
	emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
      }
    }
  }

//  Emit DRI if required --- note that DRI value could change for each scan.
//    * If it doesn't, a tiny amount of space is wasted in multiple-scan files.
//    * We assume DRI will never be nonzero for one scan and zero for a later one.
  if (cinfo->restart_interval)
    emit_dri(cinfo);

  emit_sos(cinfo);
}


//  * Write datastream trailer.

METHODDEF void
write_file_trailer (j_compress_ptr cinfo)
{
  emit_marker(cinfo, M_EOI);
}


//  * Write an abbreviated table-specification datastream.
//  * This consists of SOI, DQT and DHT tables, and EOI.
//  * Any table that is defined and not marked sent_table = TRUE will be
//  * emitted.  Note that all tables will be marked sent_table = TRUE at exit.

METHODDEF void
write_tables_only (j_compress_ptr cinfo)
{
  int i;

  emit_marker(cinfo, M_SOI);

  for (i = 0; i < NUM_QUANT_TBLS; i++) {
    if (cinfo->quant_tbl_ptrs[i] != NULL)
      (void) emit_dqt(cinfo, i);
  }

  if (! cinfo->arith_code) {
    for (i = 0; i < NUM_HUFF_TBLS; i++) {
      if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
	emit_dht(cinfo, i, FALSE);
      if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
	emit_dht(cinfo, i, TRUE);
    }
  }

  emit_marker(cinfo, M_EOI);
}


//  * Initialize the marker writer module.

GLOBAL void
jinit_marker_writer (j_compress_ptr cinfo)
{
  // Create the subobject 
  cinfo->marker = (struct jpeg_marker_writer *)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				SIZEOF(struct jpeg_marker_writer));
  // Initialize method pointers 
  cinfo->marker->write_any_marker = write_any_marker;
  cinfo->marker->write_file_header = write_file_header;
  cinfo->marker->write_frame_header = write_frame_header;
  cinfo->marker->write_scan_header = write_scan_header;
  cinfo->marker->write_file_trailer = write_file_trailer;
  cinfo->marker->write_tables_only = write_tables_only;
}