make_page_offset_hints(fz_context *ctx, pdf_document *doc, pdf_write_state *opts, fz_buffer *buf)
{
	int i, j;
	int min_objs_per_page, max_objs_per_page;
	int min_page_length, max_page_length;
	int objs_per_page_bits;
	int min_shared_object, max_shared_object;
	int max_shared_object_refs = 0;
	int min_shared_length, max_shared_length;
	page_objects **pop = &opts->page_object_lists->page[0];
	int page_len_bits, shared_object_bits, shared_object_id_bits;
	int shared_length_bits;
	int xref_len = pdf_xref_len(ctx, doc);

	min_shared_object = pdf_xref_len(ctx, doc);
	max_shared_object = 1;
	min_shared_length = opts->file_len;
	max_shared_length = 0;
	for (i=1; i < xref_len; i++)
	{
		int min, max, page;

		min = opts->ofs_list[i];
		if (i == opts->start-1 || (opts->start == 1 && i == xref_len-1))
			max = opts->main_xref_offset;
		else if (i == xref_len-1)
			max = opts->ofs_list[1];
		else
			max = opts->ofs_list[i+1];

		assert(max > min);

		if (opts->use_list[i] & USE_SHARED)
		{
			page = -1;
			if (i < min_shared_object)
				min_shared_object = i;
			if (i > max_shared_object)
				max_shared_object = i;
			if (min_shared_length > max - min)
				min_shared_length = max - min;
			if (max_shared_length < max - min)
				max_shared_length = max - min;
		}
		else if (opts->use_list[i] & (USE_CATALOGUE | USE_HINTS | USE_PARAMS))
			page = -1;
		else if (opts->use_list[i] & USE_PAGE1)
		{
			page = 0;
			if (min_shared_length > max - min)
				min_shared_length = max - min;
			if (max_shared_length < max - min)
				max_shared_length = max - min;
		}
		else if (opts->use_list[i] == 0)
			page = -1;
		else
			page = opts->use_list[i]>>USE_PAGE_SHIFT;

		if (page >= 0)
		{
			pop[page]->num_objects++;
			if (pop[page]->min_ofs > min)
				pop[page]->min_ofs = min;
			if (pop[page]->max_ofs < max)
				pop[page]->max_ofs = max;
		}
	}

	min_objs_per_page = max_objs_per_page = pop[0]->num_objects;
	min_page_length = max_page_length = pop[0]->max_ofs - pop[0]->min_ofs;
	for (i=1; i < opts->page_count; i++)
	{
		int tmp;
		if (min_objs_per_page > pop[i]->num_objects)
			min_objs_per_page = pop[i]->num_objects;
		if (max_objs_per_page < pop[i]->num_objects)
			max_objs_per_page = pop[i]->num_objects;
		tmp = pop[i]->max_ofs - pop[i]->min_ofs;
		if (tmp < min_page_length)
			min_page_length = tmp;
		if (tmp > max_page_length)
			max_page_length = tmp;
	}

	for (i=0; i < opts->page_count; i++)
	{
		int count = 0;
		page_objects *po = opts->page_object_lists->page[i];
		for (j = 0; j < po->len; j++)
		{
			if (i == 0 && opts->use_list[po->object[j]] & USE_PAGE1)
				count++;
			else if (i != 0 && opts->use_list[po->object[j]] & USE_SHARED)
				count++;
		}
		po->num_shared = count;
		if (i == 0 || count > max_shared_object_refs)
			max_shared_object_refs = count;
	}
	if (min_shared_object > max_shared_object)
		min_shared_object = max_shared_object = 0;

	/* Table F.3 - Header */
	/* Header Item 1: Least number of objects in a page */
	fz_append_bits(ctx, buf, min_objs_per_page, 32);
	/* Header Item 2: Location of first pages page object */
	fz_append_bits(ctx, buf, opts->ofs_list[pop[0]->page_object_number], 32);
	/* Header Item 3: Number of bits required to represent the difference
	 * between the greatest and least number of objects in a page. */
	objs_per_page_bits = my_log2(max_objs_per_page - min_objs_per_page);
	fz_append_bits(ctx, buf, objs_per_page_bits, 16);
	/* Header Item 4: Least length of a page. */
	fz_append_bits(ctx, buf, min_page_length, 32);
	/* Header Item 5: Number of bits needed to represent the difference
	 * between the greatest and least length of a page. */
	page_len_bits = my_log2(max_page_length - min_page_length);
	fz_append_bits(ctx, buf, page_len_bits, 16);
	/* Header Item 6: Least offset to start of content stream (Acrobat
	 * sets this to always be 0) */
	fz_append_bits(ctx, buf, 0, 32);
	/* Header Item 7: Number of bits needed to represent the difference
	 * between the greatest and least offset to content stream (Acrobat
	 * sets this to always be 0) */
	fz_append_bits(ctx, buf, 0, 16);
	/* Header Item 8: Least content stream length. (Acrobat
	 * sets this to always be 0) */
	fz_append_bits(ctx, buf, 0, 32);
	/* Header Item 9: Number of bits needed to represent the difference
	 * between the greatest and least content stream length (Acrobat
	 * sets this to always be the same as item 5) */
	fz_append_bits(ctx, buf, page_len_bits, 16);
	/* Header Item 10: Number of bits needed to represent the greatest
	 * number of shared object references. */
	shared_object_bits = my_log2(max_shared_object_refs);
	fz_append_bits(ctx, buf, shared_object_bits, 16);
	/* Header Item 11: Number of bits needed to represent the greatest
	 * shared object identifier. */
	shared_object_id_bits = my_log2(max_shared_object - min_shared_object + pop[0]->num_shared);
	fz_append_bits(ctx, buf, shared_object_id_bits, 16);
	/* Header Item 12: Number of bits needed to represent the numerator
	 * of the fractions. We always send 0. */
	fz_append_bits(ctx, buf, 0, 16);
	/* Header Item 13: Number of bits needed to represent the denominator
	 * of the fractions. We always send 0. */
	fz_append_bits(ctx, buf, 0, 16);

	/* Table F.4 - Page offset hint table (per page) */
	/* Item 1: A number that, when added to the least number of objects
	 * on a page, gives the number of objects in the page. */
	for (i = 0; i < opts->page_count; i++)
	{
		fz_append_bits(ctx, buf, pop[i]->num_objects - min_objs_per_page, objs_per_page_bits);
	}
	fz_append_bits_pad(ctx, buf);
	/* Item 2: A number that, when added to the least page length, gives
	 * the length of the page in bytes. */
	for (i = 0; i < opts->page_count; i++)
	{
		fz_append_bits(ctx, buf, pop[i]->max_ofs - pop[i]->min_ofs - min_page_length, page_len_bits);
	}
	fz_append_bits_pad(ctx, buf);
	/* Item 3: The number of shared objects referenced from the page. */
	for (i = 0; i < opts->page_count; i++)
	{
		fz_append_bits(ctx, buf, pop[i]->num_shared, shared_object_bits);
	}
	fz_append_bits_pad(ctx, buf);
	/* Item 4: Shared object id for each shared object ref in every page.
	 * Spec says "not for page 1", but acrobat does send page 1's - all
	 * as zeros. */
	for (i = 0; i < opts->page_count; i++)
	{
		for (j = 0; j < pop[i]->len; j++)
		{
			int o = pop[i]->object[j];
			if (i == 0 && opts->use_list[o] & USE_PAGE1)
				fz_append_bits(ctx, buf, 0 /* o - pop[0]->page_object_number */, shared_object_id_bits);
			if (i != 0 && opts->use_list[o] & USE_SHARED)
				fz_append_bits(ctx, buf, o - min_shared_object + pop[0]->num_shared, shared_object_id_bits);
		}
	}
	fz_append_bits_pad(ctx, buf);
	/* Item 5: Numerator of fractional position for each shared object reference. */
	/* We always send 0 in 0 bits */
	/* Item 6: A number that, when added to the least offset to the start
	 * of the content stream (F.3 Item 6), gives the offset in bytes of
	 * start of the pages content stream object relative to the beginning
	 * of the page. Always 0 in 0 bits. */
	/* Item 7: A number that, when added to the least content stream length
	 * (F.3 Item 8), gives the length of the pages content stream object.
	 * Always == Item 2 as least content stream length = least page stream
	 * length.
	 */
	for (i = 0; i < opts->page_count; i++)
	{
		fz_append_bits(ctx, buf, pop[i]->max_ofs - pop[i]->min_ofs - min_page_length, page_len_bits);
	}

	/* Pad, and then do shared object hint table */
	fz_append_bits_pad(ctx, buf);
	opts->hints_shared_offset = (int)fz_buffer_storage(ctx, buf, NULL);

	/* Table F.5: */
	/* Header Item 1: Object number of the first object in the shared
	 * objects section. */
	fz_append_bits(ctx, buf, min_shared_object, 32);
	/* Header Item 2: Location of first object in the shared objects
	 * section. */
	fz_append_bits(ctx, buf, opts->ofs_list[min_shared_object], 32);
	/* Header Item 3: The number of shared object entries for the first
	 * page. */
	fz_append_bits(ctx, buf, pop[0]->num_shared, 32);
	/* Header Item 4: The number of shared object entries for the shared
	 * objects section + first page. */
	fz_append_bits(ctx, buf, max_shared_object - min_shared_object + pop[0]->num_shared, 32);
	/* Header Item 5: The number of bits needed to represent the greatest
	 * number of objects in a shared object group (Always 0). */
	fz_append_bits(ctx, buf, 0, 16);
	/* Header Item 6: The least length of a shared object group in bytes. */
	fz_append_bits(ctx, buf, min_shared_length, 32);
	/* Header Item 7: The number of bits required to represent the
	 * difference between the greatest and least length of a shared object
	 * group. */
	shared_length_bits = my_log2(max_shared_length - min_shared_length);
	fz_append_bits(ctx, buf, shared_length_bits, 16);

	/* Table F.6 */
	/* Item 1: Shared object group length (page 1 objects) */
	for (j = 0; j < pop[0]->len; j++)
	{
		int o = pop[0]->object[j];
		int64_t min, max;
		min = opts->ofs_list[o];
		if (o == opts->start-1)
			max = opts->main_xref_offset;
		else if (o < xref_len-1)
			max = opts->ofs_list[o+1];
		else
			max = opts->ofs_list[1];
		if (opts->use_list[o] & USE_PAGE1)
			fz_append_bits(ctx, buf, max - min - min_shared_length, shared_length_bits);
	}
	/* Item 1: Shared object group length (shared objects) */
	for (i = min_shared_object; i <= max_shared_object; i++)
	{
		int min, max;
		min = opts->ofs_list[i];
		if (i == opts->start-1)
			max = opts->main_xref_offset;
		else if (i < xref_len-1)
			max = opts->ofs_list[i+1];
		else
			max = opts->ofs_list[1];
		fz_append_bits(ctx, buf, max - min - min_shared_length, shared_length_bits);
	}
	fz_append_bits_pad(ctx, buf);

	/* Item 2: MD5 presence flags */
	for (i = max_shared_object - min_shared_object + pop[0]->num_shared; i > 0; i--)
	{
		fz_append_bits(ctx, buf, 0, 1);
	}
	fz_append_bits_pad(ctx, buf);
	/* Item 3: MD5 sums (not present) */
	fz_append_bits_pad(ctx, buf);
	/* Item 4: Number of objects in the group (not present) */
}