/*

 * jcmarker.c

 *

 * Copyright (C) 1991-1998, 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;

/* Private state */

typedef struct {

  struct jpeg_marker_writer pub; /* public fields */

  unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */

} my_marker_writer;

typedef my_marker_writer * my_marker_ptr;

/*

 * 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++) {

      /* The table entries must be emitted in zigzag order. */

      unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];

      if (prec)

	emit_byte(cinfo, (int) (qval >> 8));

      emit_byte(cinfo, (int) (qval & 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 - major first)

   * 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);

  emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */

  emit_byte(cinfo, cinfo->JFIF_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;

  }

}

/*

 * These routines allow writing an arbitrary marker with parameters.

 * The only intended use is to emit COM or APPn markers after calling

 * write_file_header and before calling write_frame_header.

 * Other uses are not guaranteed to produce desirable results.

 * Counting the parameter bytes properly is the caller's responsibility.

 */

METHODDEF(void)

write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)

/* Emit an arbitrary marker header */

{

  if (datalen > (unsigned int) 65533)		/* safety check */

    ERREXIT(cinfo, JERR_BAD_LENGTH);

  emit_marker(cinfo, (JPEG_MARKER) marker);

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

}

METHODDEF(void)

write_marker_byte (j_compress_ptr cinfo, int val)

/* Emit one byte of marker parameters following write_marker_header */

{

  emit_byte(cinfo, val);

}

/*

 * 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)

{

  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;

  emit_marker(cinfo, M_SOI);	/* first the SOI */

  /* SOI is defined to reset restart interval to 0 */

  marker->last_restart_interval = 0;

  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);

    }

  }