/*
    jbig2dec
    
    Copyright (c) 2004 artofcode LLC.
    
    This software is provided AS-IS with no warranty,
    either express or implied.
                                                                                
    This software is distributed under license and may not
    be copied, modified or distributed except as expressly
    authorized under the terms of the license contained in
    the file LICENSE in this distribution.
                                                                                
    For information on commercial licensing, go to
    http://www.artifex.com/licensing/ or contact
    Artifex Software, Inc.,  101 Lucas Valley Road #110,
    San Rafael, CA  94903, U.S.A., +1(415)492-9861.
                                                                                
    $Id: jbig2_refinement.c 6300 2005-12-28 19:56:24Z giles $
*/

/**
 * Generic Refinement region handlers.
 **/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif 
#include "os_types.h"

#include <stddef.h>
#include <string.h> /* memcpy(), memset() */

#include <stdio.h>

#include "jbig2.h"
#include "jbig2_priv.h"
#include "jbig2_arith.h"
#include "jbig2_generic.h"
#include "jbig2_mmr.h"
#include "jbig2_image.h"

static int
jbig2_decode_refinement_template0(Jbig2Ctx *ctx,
                              Jbig2Segment *segment,
                              const Jbig2RefinementRegionParams *params,
                              Jbig2ArithState *as,
                              Jbig2Image *image,
                              Jbig2ArithCx *GR_stats)
{
  return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
    "refinement region template 0 NYI");
}

static int
jbig2_decode_refinement_template0_unopt(Jbig2Ctx *ctx,
                              Jbig2Segment *segment,
                              const Jbig2RefinementRegionParams *params,
                              Jbig2ArithState *as,
                              Jbig2Image *image,
                              Jbig2ArithCx *GR_stats)
{
  const int GRW = image->width;
  const int GRH = image->height;
  const int dx = params->DX;
  const int dy = params->DY;
  Jbig2Image *ref = params->reference;
  uint32_t CONTEXT;
  int x,y;
  bool bit;

  for (y = 0; y < GRH; y++) {
    for (x = 0; x < GRW; x++) {
      CONTEXT = 0;
      CONTEXT |= jbig2_image_get_pixel(image, x - 1, y + 0) << 0; 
      CONTEXT |= jbig2_image_get_pixel(image, x + 1, y - 1) << 1; 
      CONTEXT |= jbig2_image_get_pixel(image, x + 0, y - 1) << 2; 
      CONTEXT |= jbig2_image_get_pixel(image, x + params->grat[0], 
	y + params->grat[1]) << 3; 
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+1, y-dy+1) << 4;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy+1) << 5;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx-1, y-dy+1) << 6;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+1, y-dy+0) << 7;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy+0) << 8;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx-1, y-dy+0) << 9;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+1, y-dy-1) << 10;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy-1) << 11;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+params->grat[2], 
	y-dy+params->grat[3]) << 12;
      bit = jbig2_arith_decode(as, &GR_stats[CONTEXT]);
      jbig2_image_set_pixel(image, x, y, bit);
    }
  }
#ifdef JBIG2_DEBUG
  {
    static count = 0;
    char name[32];
    snprintf(name, 32, "refin-%d.pbm", count);
    jbig2_image_write_pbm_file(ref, name);
    snprintf(name, 32, "refout-%d.pbm", count);
    jbig2_image_write_pbm_file(image, name);
    count++;
  }
#endif

  return 0;
}


static int
jbig2_decode_refinement_template1_unopt(Jbig2Ctx *ctx,
                              Jbig2Segment *segment,
                              const Jbig2RefinementRegionParams *params,
                              Jbig2ArithState *as,
                              Jbig2Image *image,
                              Jbig2ArithCx *GR_stats)
{
  const int GRW = image->width;
  const int GRH = image->height;
  const int dx = params->DX;
  const int dy = params->DY;
  Jbig2Image *ref = params->reference;
  uint32_t CONTEXT;
  int x,y;
  bool bit;

  for (y = 0; y < GRH; y++) {
    for (x = 0; x < GRW; x++) {
      CONTEXT = 0;
      CONTEXT |= jbig2_image_get_pixel(image, x - 1, y + 0) << 0; 
      CONTEXT |= jbig2_image_get_pixel(image, x + 1, y - 1) << 1; 
      CONTEXT |= jbig2_image_get_pixel(image, x + 0, y - 1) << 2; 
      CONTEXT |= jbig2_image_get_pixel(image, x - 1, y - 1) << 3; 
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+1, y-dy+1) << 4;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy+1) << 5;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+1, y-dy+0) << 6;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy+0) << 7;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx-1, y-dy+0) << 8;
      CONTEXT |= jbig2_image_get_pixel(ref, x-dx+0, y-dy-1) << 9;
      bit = jbig2_arith_decode(as, &GR_stats[CONTEXT]);
      jbig2_image_set_pixel(image, x, y, bit);
    }
  }

#ifdef JBIG2_DEBUG
  {
    static count = 0;
    char name[32];
    snprintf(name, 32, "refin-%d.pbm", count);
    jbig2_image_write_pbm_file(ref, name);
    snprintf(name, 32, "refout-%d.pbm", count);
    jbig2_image_write_pbm_file(image, name);
    count++;
  }
#endif

  return 0;
}

static int
jbig2_decode_refinement_template1(Jbig2Ctx *ctx,
                              Jbig2Segment *segment,
                              const Jbig2RefinementRegionParams *params,
                              Jbig2ArithState *as,
                              Jbig2Image *image,
                              Jbig2ArithCx *GR_stats)
{
  const int GRW = image->width;
  const int GRH = image->height;
  const int stride = image->stride;
  const int refstride = params->reference->stride;
  const int dx = params->DX;
  const int dy = params->DY;
  byte *grreg_line = (byte *)image->data;
  byte *grref_line = (byte *)params->reference->data;
  int x,y;

  for (y = 0; y < GRH; y++) {
    const int padded_width = (GRW + 7) & -8;
    uint32_t CONTEXT;
    uint32_t refline_m1; /* previous line of the reference bitmap */
    uint32_t refline_0;  /* current line of the reference bitmap */
    uint32_t refline_1;  /* next line of the reference bitmap */
    uint32_t line_m1;    /* previous line of the decoded bitmap */

    line_m1 = (y >= 1) ? grreg_line[-stride] : 0;
    refline_m1 = ((y-dy) >= 1) ? grref_line[(-1-dy)*stride] << 2: 0;
    refline_0  = (((y-dy) > 0) && ((y-dy) < GRH)) ? grref_line[(0-dy)*stride] << 4 : 0;
    refline_1  = (y < GRH - 1) ? grref_line[(+1-dy)*stride] << 7 : 0;
    CONTEXT = ((line_m1 >> 5) & 0x00e) |
	      ((refline_1 >> 5) & 0x030) |
	      ((refline_0 >> 5) & 0x1c0) |
	      ((refline_m1 >> 5) & 0x200);

    for (x = 0; x < padded_width; x += 8) {
      byte result = 0;
      int x_minor;
      const int minor_width = GRW - x > 8 ? 8 : GRW - x;

      if (y >= 1) {
	line_m1 = (line_m1 << 8) | 
	  (x + 8 < GRW ? grreg_line[-stride + (x >> 3) + 1] : 0);
	refline_m1 = (refline_m1 << 8) | 
	  (x + 8 < GRW ? grref_line[-refstride + (x >> 3) + 1] << 2 : 0);
      }

      refline_0 = (refline_0 << 8) |
	  (x + 8 < GRW ? grref_line[(x >> 3) + 1] << 4 : 0);

      if (y < GRH - 1)
	refline_1 = (refline_1 << 8) |
	  (x + 8 < GRW ? grref_line[+refstride + (x >> 3) + 1] << 7 : 0);
      else
	refline_1 = 0;

      /* this is the speed critical inner-loop */
      for (x_minor = 0; x_minor < minor_width; x_minor++) {
	bool bit;

	bit = jbig2_arith_decode(as, &GR_stats[CONTEXT]);
	result |= bit << (7 - x_minor);
	CONTEXT = ((CONTEXT & 0x0d6) << 1) | bit |
	  ((line_m1 >> (9 - x_minor)) & 0x002) |
	  ((refline_1 >> (9 - x_minor)) & 0x010) |
	  ((refline_0 >> (9 - x_minor)) & 0x040) |
	  ((refline_m1 >> (9 - x_minor)) & 0x200);
      }

      grreg_line[x>>3] = result;

    }

    grreg_line += stride;
    grref_line += refstride;

  }

  return 0;

}


/**
 * jbig2_decode_refinement_region: Decode a generic refinement region.
 * @ctx: The context for allocation and error reporting.
 * @segment: A segment reference for error reporting.
 * @params: Decoding parameter set.
 * @as: Arithmetic decoder state.
 * @image: Where to store the decoded image.
 * @GR_stats: Arithmetic stats.
 *
 * Decodes a generic refinement region, according to section 6.3.
 * an already allocated Jbig2Image object in @image for the result.
 *
 * Because this API is based on an arithmetic decoding state, it is
 * not suitable for MMR decoding.
 *
 * Return code: 0 on success.
 **/
int
jbig2_decode_refinement_region(Jbig2Ctx *ctx,
			    Jbig2Segment *segment,
			    const Jbig2RefinementRegionParams *params,
			    Jbig2ArithState *as,
			    Jbig2Image *image,
			    Jbig2ArithCx *GR_stats)
{
  {
    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
      "decoding generic refinement region with offset %d,%x,\n"
      "  GRTEMPLATE=%d, TPGRON=%d, RA1=(%d,%d) RA2=(%d,%d)\n",
      params->DX, params->DY, params->GRTEMPLATE, params->TPGRON,
      params->grat[0], params->grat[1], params->grat[2], params->grat[3]);
  }
  if (params->TPGRON)
    return jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
        "decode_refinement_region: typical prediction coding NYI");
  if (params->GRTEMPLATE)
    return jbig2_decode_refinement_template1_unopt(ctx, segment, params, 
                                             as, image, GR_stats);
  else
    return jbig2_decode_refinement_template0_unopt(ctx, segment, params,
                                             as, image, GR_stats);
}

/**
 * Find the first referred-to intermediate region segment
 * with a non-NULL result for use as a reference image
 */
Jbig2Segment *
jbig2_region_find_referred(Jbig2Ctx *ctx,Jbig2Segment *segment)
{
  const int nsegments = segment->referred_to_segment_count;
  Jbig2Segment *rsegment;
  int index;

  for (index = 0; index < nsegments; index++) {
    rsegment = jbig2_find_segment(ctx, 
      segment->referred_to_segments[index]);
    if (rsegment == NULL) {
      jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
        "could not find referred to segment %d",
        segment->referred_to_segments[index]);
      continue;
    }
    switch (rsegment->flags & 63) {
      case 4:  /* intermediate text region */
      case 20: /* intermediate halftone region */
      case 36: /* intermediate generic region */
      case 40: /* intermediate generic refinement region */
        if (rsegment->result) return rsegment;
	break;
      default: /* keep looking */
        break;
    }
  }
  /* no appropriate reference was found. */
  return NULL;
}

/** 
 * Handler for generic refinement region segments
 */
int
jbig2_refinement_region(Jbig2Ctx *ctx, Jbig2Segment *segment,
                               const byte *segment_data)
{
  Jbig2RefinementRegionParams params;
  Jbig2RegionSegmentInfo rsi;
  int offset = 0;
  byte seg_flags;
  
  /* 7.4.7 */
  if (segment->data_length < 18)
    return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
                       "Segment too short");

  jbig2_get_region_segment_info(&rsi, segment_data);
  jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
              "generic region: %d x %d @ (%d, %d), flags = %02x",
              rsi.width, rsi.height, rsi.x, rsi.y, rsi.flags);

  /* 7.4.7.2 */
  seg_flags = segment_data[17];
  params.GRTEMPLATE = seg_flags & 0x01;
  params.TPGRON = seg_flags & 0x02 ? 1 : 0;
  jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
              "segment flags = %02x %s%s", seg_flags,
              params.GRTEMPLATE ? " GRTEMPLATE" :"",
              params.TPGRON ? " TPGRON" : "" );
  if (seg_flags & 0xFC)
    jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
                "reserved segment flag bits are non-zero");
  offset += 18;

  /* 7.4.7.3 */
  if (!params.GRTEMPLATE) {
    if (segment->data_length < 22)
      return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
                         "Segment too short");
    params.grat[0] = segment_data[offset + 0];
    params.grat[1] = segment_data[offset + 1];
    params.grat[2] = segment_data[offset + 2];
    params.grat[3] = segment_data[offset + 3];
    jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
                   "grat1: (%d, %d) grat2: (%d, %d)", 
                   params.grat[0], params.grat[1],
                   params.grat[2], params.grat[3]);
    offset += 4;
  }

  /* 7.4.7.4 - set up the reference image */
  if (segment->referred_to_segment_count) {
    Jbig2Segment *ref;

    ref = jbig2_region_find_referred(ctx, segment);
    if (ref == NULL)
      return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
        "could not find reference bitmap!");
    /* the reference bitmap is the result of a previous 
       intermediate region segment; the reference selection
       rules say to use the first one available, and not to
       reuse any intermediate result, so we simply clone it
       and free the original to keep track of this. */
    params.reference = jbig2_image_clone(ctx, ref->result);
    jbig2_image_release(ctx, ref->result);
    ref->result = NULL;
    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
      "found reference bitmap in segment %d", ref->number);
  } else {
    /* the reference is just (a subset of) the page buffer */
    params.reference = jbig2_image_clone(ctx, 
      ctx->pages[ctx->current_page].image);
    /* TODO: subset the image if appropriate */
  }

  /* 7.4.7.5 */
  params.DX = 0;
  params.DY = 0;
  {
    Jbig2WordStream *ws;
    Jbig2ArithState *as;
    Jbig2ArithCx *GR_stats = NULL;
    int stats_size;
    Jbig2Image *image;
    int code;

    image = jbig2_image_new(ctx, rsi.width, rsi.height);
    if (image == NULL)
      return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
               "unable to allocate image storage");
    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
      "allocated %d x %d image buffer for region decode results",
          rsi.width, rsi.height);

    stats_size = params.GRTEMPLATE ? 1 << 10 : 1 << 13;
    GR_stats = jbig2_alloc(ctx->allocator, stats_size);
    memset(GR_stats, 0, stats_size);

    ws = jbig2_word_stream_buf_new(ctx, segment_data + offset,
           segment->data_length - offset);
    as = jbig2_arith_new(ctx, ws);
    code = jbig2_decode_refinement_region(ctx, segment, &params,
                              as, image, GR_stats);

    jbig2_free(ctx->allocator, as);
    jbig2_word_stream_buf_free(ctx, ws);
    jbig2_free(ctx->allocator, GR_stats);

    if ((segment->flags & 63) == 40) {
        /* intermediate region. save the result for later */
	segment->result = image;
    } else {
	/* immediate region. composite onto the page */
        jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
            "composing %dx%d decoded refinement region onto page at (%d, %d)",
            rsi.width, rsi.height, rsi.x, rsi.y);
	jbig2_page_add_result(ctx, &ctx->pages[ctx->current_page],
          image, rsi.x, rsi.y, rsi.op);
        jbig2_image_release(ctx, image);
    }
  }

  return 0;
}
