/*
    jbig2dec
    
    Copyright (c) 2001-2002 artofcode LLC.
    
    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 259 2003-06-14 09:40:02Z 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 "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 byte *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 */
                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;
    }
    
    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 {
        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_complete_page: complete a page image
 *
 * called upon seeing an 'end of page' segment, this routine
 * marks a page as completed. final compositing and output
 * of the page image will also happen from here (NYI)
 **/
int
jbig2_complete_page (Jbig2Ctx *ctx)
{
    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 byte *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_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;
}
