/* * 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 */