/*
    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_image.c 8022 2007-06-05 22:23:38Z giles $
*/

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

#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* memcpy() */

#include "jbig2.h"
#include "jbig2_priv.h"
#include "jbig2_image.h"


/* allocate a Jbig2Image structure and its associated bitmap */
Jbig2Image* jbig2_image_new(Jbig2Ctx *ctx, int width, int height)
{
	Jbig2Image	*image;
	int		stride;
	
	image = (Jbig2Image *)jbig2_alloc(ctx->allocator, sizeof(*image));
	if (image == NULL) {
		jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1,
			       "could not allocate image structure");
		return NULL;
	}
	
	stride = ((width - 1) >> 3) + 1; /* generate a byte-aligned stride */
	image->data = (uint8_t *)jbig2_alloc(ctx->allocator, stride*height);
	if (image->data == NULL) {
                jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1,
                    "could not allocate image data buffer! [%d bytes]\n", stride*height);
		jbig2_free(ctx->allocator, image);
		return NULL;
	}

	image->width = width;
	image->height = height;
	image->stride = stride;
	image->refcount = 1;

	return image;
}

/* clone an image pointer by bumping its reference count */
Jbig2Image* jbig2_image_clone(Jbig2Ctx *ctx, Jbig2Image *image)
{
	image->refcount++;
	return image;
}

/* release an image pointer, freeing it it appropriate */
void jbig2_image_release(Jbig2Ctx *ctx, Jbig2Image *image)
{
	image->refcount--;
	if (!image->refcount) jbig2_image_free(ctx, image);
}

/* free a Jbig2Image structure and its associated memory */
void jbig2_image_free(Jbig2Ctx *ctx, Jbig2Image *image)
{
	jbig2_free(ctx->allocator, image->data);
	jbig2_free(ctx->allocator, image);
}

/* resize a Jbig2Image */
Jbig2Image *jbig2_image_resize(Jbig2Ctx *ctx, Jbig2Image *image, 
				int width, int height)
{
	if (width == image->width) {
	    /* use the same stride, just change the length */
	    image->data = jbig2_realloc(ctx->allocator,
                image->data, image->stride*height);
            if (image->data == NULL) {
                jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1,
                    "could not resize image buffer!");
		return NULL;
            }
	    if (height > image->height) {
		memset(image->data + image->height*image->stride,
			0, (height - image->height)*image->stride);
	    }
            image->height = height;

	} else {
	    /* we must allocate a new image buffer and copy */
	    jbig2_error(ctx, JBIG2_SEVERITY_WARNING, -1,
		"jbig2_image_resize called with a different width (NYI)");
	}

	return NULL;
}

/* composite one jbig2_image onto another
   slow but general version */
int jbig2_image_compose_unopt(Jbig2Ctx *ctx,
			Jbig2Image *dst, Jbig2Image *src,
                        int x, int y, Jbig2ComposeOp op)
{
    int i, j;
    int sw = src->width;
    int sh = src->height;
    int sx = 0;
    int sy = 0;

    /* clip to the dst image boundaries */
    if (x < 0) { sx += -x; sw -= -x; x = 0; }
    if (y < 0) { sy += -y; sh -= -y; y = 0; }
    if (x + sw >= dst->width) sw = dst->width - x;
    if (y + sh >= dst->height) sh = dst->height - y;

    switch (op) {
	case JBIG2_COMPOSE_OR:
	    for (j = 0; j < sh; j++) {
		for (i = 0; i < sw; i++) {
		    jbig2_image_set_pixel(dst, i+x, j+y,
			jbig2_image_get_pixel(src, i+sx, j+sy) |
			jbig2_image_get_pixel(dst, i+x, j+y));
		}
    	    }
	    break;
	case JBIG2_COMPOSE_AND:
	    for (j = 0; j < sh; j++) {
		for (i = 0; i < sw; i++) {
		    jbig2_image_set_pixel(dst, i+x, j+y,
			jbig2_image_get_pixel(src, i+sx, j+sy) &
			jbig2_image_get_pixel(dst, i+x, j+y));
		}
    	    }
	    break;
	case JBIG2_COMPOSE_XOR:
	    for (j = 0; j < sh; j++) {
		for (i = 0; i < sw; i++) {
		    jbig2_image_set_pixel(dst, i+x, j+y,
			jbig2_image_get_pixel(src, i+sx, j+sy) ^
			jbig2_image_get_pixel(dst, i+x, j+y));
		}
    	    }
	    break;
	case JBIG2_COMPOSE_XNOR:
	    for (j = 0; j < sh; j++) {
		for (i = 0; i < sw; i++) {
		    jbig2_image_set_pixel(dst, i+x, j+y,
			~(jbig2_image_get_pixel(src, i+sx, j+sy) ^
			jbig2_image_get_pixel(dst, i+x, j+y)));
		}
    	    }
	    break;
	case JBIG2_COMPOSE_REPLACE:
	    for (j = 0; j < sh; j++) {
		for (i = 0; i < sw; i++) {
		    jbig2_image_set_pixel(dst, i+x, j+y,
			jbig2_image_get_pixel(src, i+sx, j+sy));
		}
    	    }
	    break;
    }

    return 0;
}

/* composite one jbig2_image onto another */
int jbig2_image_compose(Jbig2Ctx *ctx, Jbig2Image *dst, Jbig2Image *src, 
			int x, int y, Jbig2ComposeOp op)
{
    int i, j;
    int w, h;
    int leftbyte, rightbyte;
    int shift;
    uint8_t *s, *ss;
    uint8_t *d, *dd;
    uint8_t mask, rightmask;
    
    if (op != JBIG2_COMPOSE_OR) {
	/* hand off the the general routine */
	return jbig2_image_compose_unopt(ctx, dst, src, x, y, op);
    }

    /* clip */
    w = src->width;
    h = src->height;
    ss = src->data;
    /* FIXME: this isn't sufficient for the < 0 cases */
    if (x < 0) { w += x; x = 0; }
    if (y < 0) { h += y; y = 0; } 
    w = (x + w < dst->width) ? w : dst->width - x;
    h = (y + h < dst->height) ? h : dst->height - y;
#ifdef JBIG2_DEBUG    
    jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, -1,
      "composting %dx%d at (%d, %d) afer clipping\n",
        w, h, x, y);
#endif
    
#if 0
    /* special case complete/strip replacement */
    /* disabled because it's only safe to do when the destination
       buffer is all-blank. */
    if ((x == 0) && (w == src->width)) {
        memcpy(dst->data + y*dst->stride, src->data, h*src->stride);
        return 0;
    }
#endif

    leftbyte = x >> 3;
    rightbyte = (x + w - 1) >> 3;
    shift = x & 7;
    
    /* general OR case */    
    s = ss;
    d = dd = dst->data + y*dst->stride + leftbyte;
    if (leftbyte == rightbyte) {
	mask = 0x100 - (0x100 >> w);
        for (j = 0; j < h; j++) {
            *d |= (*s & mask) >> shift;
            d += dst->stride;
            s += src->stride;
        }
    } else if (shift == 0) {
	rightmask = (w & 7) ? 0x100 - (1 << (8 - (w & 7))) : 0xFF;
        for (j = 0; j < h; j++) {
	    for (i = leftbyte; i < rightbyte; i++)
		*d++ |= *s++;
	    *d |= *s & rightmask;
            d = (dd += dst->stride);
            s = (ss += src->stride);
	}
    } else {
	bool overlap = (((w + 7) >> 3) < ((x + w + 7) >> 3) - (x >> 3));
	mask = 0x100 - (1 << shift);
	if (overlap)
	    rightmask = (0x100 - (0x100 >> ((x + w) & 7))) >> (8 - shift);
	else
	    rightmask = 0x100 - (0x100 >> (w & 7));
        for (j = 0; j < h; j++) {
	    *d++ |= (*s & mask) >> shift;
            for(i = leftbyte; i < rightbyte - 1; i++) {
		*d |= ((*s++ & ~mask) << (8 - shift));
		*d++ |= ((*s & mask) >> shift);
	    }
	    if (overlap)
		*d |= (*s & rightmask) << (8 - shift);
	    else
		*d |= ((s[0] & ~mask) << (8 - shift)) |
		    ((s[1] & rightmask) >> shift);
	    d = (dd += dst->stride);
	    s = (ss += src->stride);
	}
    }
            
    return 0;
}


/* initialize an image bitmap to a constant value */
void jbig2_image_clear(Jbig2Ctx *ctx, Jbig2Image *image, int value)
{
    const uint8_t fill = value ? 0xFF : 0x00;

    memset(image->data, fill, image->stride*image->height);
}

/* look up a pixel value in an image.
   returns 0 outside the image frame for the convenience of
   the template code
*/
int jbig2_image_get_pixel(Jbig2Image *image, int x, int y)
{
  const int w = image->width;
  const int h = image->height;
  const int byte = (x >> 3) + y*image->stride;
  const int bit = 7 - (x & 7);

  if ((x < 0) || (x >= w)) return 0;
  if ((y < 0) || (y >= h)) return 0;
  
  return ((image->data[byte]>>bit) & 1);
}

/* set an individual pixel value in an image */
int jbig2_image_set_pixel(Jbig2Image *image, int x, int y, bool value)
{
  const int w = image->width;
  const int h = image->height;
  int scratch, mask;
  int bit, byte;

  if ((x < 0) || (x >= w)) return 0;
  if ((y < 0) || (y >= h)) return 0;

  byte = (x >> 3) + y*image->stride;
  bit = 7 - (x & 7);
  mask = (1 << bit) ^ 0xff;

  scratch = image->data[byte] & mask;
  image->data[byte] = scratch | (value << bit);

  return 1;
}
