/*
    jbig2dec
    
    Copyright (C) 2001-2005 Artifex Software, Inc.
    
    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_page.c 8778 2008-05-26 19:04:05Z giles $
*/

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

#include <stdlib.h>

#include "jbig2.h"
#include "jbig2_priv.h"

#ifdef OUTPUT_PBM
#include <stdio.h>
#include "jbig2_image.h"
#endif

/* dump the page struct info */
static void
dump_page_info(Jbig2Ctx *ctx, Jbig2Segment *segment, Jbig2Page *page)
{
    if (page->x_resolution == 0) {
        jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
            "page %d image is %dx%d (unknown res)", page->number,
            page->width, page->height);
    } else if (page->x_resolution == page->y_resolution) {
        jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
            "page %d image is %dx%d (%d ppm)", page->number,
            page->width, page->height,
            page->x_resolution);
    } else {
        jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
            "page %d image is %dx%d (%dx%d ppm)", page->number,
            page->width, page->height,
            page->x_resolution, page->y_resolution);
    }
    if (page->striped) {
        jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
            "\tmaximum stripe size: %d", page->stripe_size);
    }
}

/**
 * jbig2_read_page_info: parse page info segment
 *
 * parse the page info segment data and fill out a corresponding
 * Jbig2Page struct is returned, including allocating an image
 * buffer for the page (or the first stripe)
 **/
int
jbig2_parse_page_info (Jbig2Ctx *ctx, Jbig2Segment *segment, const uint8_t *segment_data)
{
    Jbig2Page *page;

    /* a new page info segment implies the previous page is finished */
    page = &(ctx->pages[ctx->current_page]);
    if ((page->number != 0) &&
            ((page->state == JBIG2_PAGE_NEW) || (page->state == JBIG2_PAGE_FREE))) {
        page->state = JBIG2_PAGE_COMPLETE;
        jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
            "unexpected page info segment, marking previous page finished");
    }
        
    /* find a free page */
    {
        int index, j;
        index = ctx->current_page;
        while (ctx->pages[index].state != JBIG2_PAGE_FREE) {
            index++;
            if (index >= ctx->max_page_index) { /* FIXME: should also look for freed pages? */
                /* grow the list */
		ctx->pages = jbig2_realloc(ctx->allocator, ctx->pages,
			(ctx->max_page_index <<= 2) * sizeof(Jbig2Page));
                for (j=index; j < ctx->max_page_index; j++) {
                    /* note to raph: and look, it gets worse! */
                    ctx->pages[j].state = JBIG2_PAGE_FREE;
                    ctx->pages[j].number = 0;
                    ctx->pages[j].image = NULL;

                }
            }
        }
        page = &(ctx->pages[index]);
        ctx->current_page = index;
        page->state = JBIG2_PAGE_NEW;
        page->number = segment->page_association;
    }
    
    /* FIXME: would be nice if we tried to work around this */
    if (segment->data_length < 19) {
        return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
            "segment too short");
    }
    
    /* 7.4.8.x */
    page->width = jbig2_get_int32(segment_data);
    page->height = jbig2_get_int32(segment_data + 4);
    
    page->x_resolution = jbig2_get_int32(segment_data + 8);
    page->y_resolution = jbig2_get_int32(segment_data + 12);
    page->flags = segment_data[16];

    /* 7.4.8.6 */
    {
        int16_t striping = jbig2_get_int16(segment_data +17);
        if (striping & 0x8000) {
            page->striped = TRUE;
            page->stripe_size = striping & 0x7FFF;
        } else {
            page->striped = FALSE;
            page->stripe_size = 0;	/* would page->height be better? */
        }
    }
    if (page->height == 0xFFFFFFFF && page->striped == FALSE) {
        jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
            "height is unspecified but page is not markes as striped");
        page->striped = TRUE;
    }
    page->end_row = 0;
    
    if (segment->data_length > 19) {
        jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
            "extra data in segment");
    }
    
    dump_page_info(ctx, segment, page);

    /* allocate an approprate page image buffer */
    /* 7.4.8.2 */
    if (page->height == 0xFFFFFFFF) {
        page->image = jbig2_image_new(ctx, page->width, page->stripe_size);
    } else {
        page->image = jbig2_image_new(ctx, page->width, page->height);
    }
    if (page->image == NULL) {
        jbig2_free(ctx->allocator, page);
        return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
            "failed to allocate buffer for page image");
    } else {
	/* 8.2 (3) fill the page with the default pixel value */
	jbig2_image_clear(ctx, page->image, (page->flags & 4));
        jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
            "allocated %dx%d page image (%d bytes)",
            page->image->width, page->image->height,
            page->image->stride*page->image->height);
    }
    
    return 0;
}

/**
 * jbig2_parse_end_of_stripe: parse an end of stripe segment
 **/
int
jbig2_parse_end_of_stripe(Jbig2Ctx *ctx, Jbig2Segment *segment, const uint8_t *segment_data)
{
    Jbig2Page page = ctx->pages[ctx->current_page];
    int end_row;

    end_row = jbig2_get_int32(segment_data);
    if (end_row < page.end_row) {
	jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
	    "end of stripe segment with non-positive end row advance"
	    "(new end row %d vs current end row %d)", 
	    end_row, page.end_row);
    } else {
	jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
	    "end of stripe: advancing end row to %d", end_row);
    }
    
    page.end_row = end_row;

    return 0;
}

/**
 * jbig2_complete_page: complete a page image
 *
 * called upon seeing an 'end of page' segment, this routine
 * marks a page as completed so it can be returned.
 * compositing will have already happened in the previous
 * segment handlers.
 **/
int
jbig2_complete_page (Jbig2Ctx *ctx)
{

    /* check for unfinished segments */
    if (ctx->segment_index != ctx->n_segments) {
      Jbig2Segment *segment = ctx->segments[ctx->segment_index];
      int code = 0;
      /* Some versions of Xerox Workcentre generate PDF files
         with the segment data length field of the last segment
         set to -1. Try to cope with this here. */
      if ((segment->data_length & 0xffffffff) == 0xffffffff) {
        jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
          "File has an invalid segment data length!"
          " Trying to decode using the available data.");
        segment->data_length = ctx->buf_wr_ix - ctx->buf_rd_ix;
        code = jbig2_parse_segment(ctx, segment, ctx->buf + ctx->buf_rd_ix);
        ctx->buf_rd_ix += segment->data_length;
        ctx->segment_index++;
      }
    }
    ctx->pages[ctx->current_page].state = JBIG2_PAGE_COMPLETE;

    return 0;
}

/**
 * jbig2_parse_end_of_page: parse an end of page segment
 **/
int
jbig2_parse_end_of_page(Jbig2Ctx *ctx, Jbig2Segment *segment, const uint8_t *segment_data)
{
    uint32_t page_number = ctx->pages[ctx->current_page].number;

    if (segment->page_association != page_number) {
        jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
            "end of page marker for page %d doesn't match current page number %d",
            segment->page_association, page_number);
    }
    
    jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
        "end of page %d", page_number);

    jbig2_complete_page(ctx);
    
#ifdef OUTPUT_PBM
    jbig2_image_write_pbm(ctx->pages[ctx->current_page].image, stdout);
#endif

    return 0;
}

/**
 * jbig2_add_page_result: composite a decoding result onto a page
 *
 * this is called to add the results of segment decode (when it
 * is an image) to a page image buffer
 **/
int
jbig2_page_add_result(Jbig2Ctx *ctx, Jbig2Page *page, Jbig2Image *image,
		      int x, int y, Jbig2ComposeOp op)
{
    /* grow the page to accomodate a new stripe if necessary */
    if (page->striped) {
	int new_height = y + image->height + page->end_row;
	if (page->image->height < new_height) {
	    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, -1,
		"growing page buffer to %d rows "
		"to accomodate new stripe", new_height);
	    jbig2_image_resize(ctx, page->image,
		page->image->width, new_height);
	}
    }    

    jbig2_image_compose(ctx, page->image, image,
                        x, y + page->end_row, JBIG2_COMPOSE_OR);

    return 0;
}

/**
 * jbig2_get_page: return the next available page image buffer
 *
 * the client can call this at any time to check if any pages
 * have been decoded. If so, it returns the first available
 * one. The client should then call jbig2_release_page() when
 * it no longer needs to refer to the image buffer.
 *
 * since this is a public routine for the library clients, we
 * return an image structure pointer, even though the function
 * name refers to a page; the page structure is private.
 **/
Jbig2Image *jbig2_page_out(Jbig2Ctx *ctx)
{
    int index;

    /* search for a completed page */
    for (index=0; index < ctx->max_page_index; index++) {
        if (ctx->pages[index].state == JBIG2_PAGE_COMPLETE) {
            ctx->pages[index].state = JBIG2_PAGE_RETURNED;
            jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, -1,
                "page %d returned to the client", ctx->pages[index].number);
            return ctx->pages[index].image;
        }
    }
    
    /* no pages available */
    return NULL;
}

/**
 * jbig2_release_page: tell the library a page can be freed
 **/
int jbig2_release_page(Jbig2Ctx *ctx, Jbig2Image *image)
{
    int index;
    
    /* find the matching page struct and mark it released */
    for (index = 0; index < ctx->max_page_index; index++) {
        if (ctx->pages[index].image == image) {
            /* todo: free associated image */
            ctx->pages[index].state = JBIG2_PAGE_RELEASED;
            jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, -1,
                "page %d released by the client", ctx->pages[index].number);
            return 0;
        }
    }
    
    /* no matching pages */
    jbig2_error(ctx, JBIG2_SEVERITY_WARNING, -1,
        "jbig2_release_page called on unknown page");
    return 1;
}
