io-bmp.c 33.6 KB
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/* -*- mode: C; c-file-style: "linux" -*- */
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/* GdkPixbuf library - Windows Bitmap image loader
 *
 * Copyright (C) 1999 The Free Software Foundation
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 *
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 * Authors: Arjan van de Ven <arjan@fenrus.demon.nl>
 *          Federico Mena-Quintero <federico@gimp.org>
 *
 * Based on io-ras.c
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 *
 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
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 */

#include <config.h>
#include <stdio.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <string.h>
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#include "gdk-pixbuf-private.h"
#include "gdk-pixbuf-io.h"
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#define DUMPBIH 0
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#if 0
/* If these structures were unpacked, they would define the two headers of the
 * BMP file.  After them comes the palette, and then the image data.
 *
 * We do not use these structures; we just keep them here for reference.
 */
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struct BitmapFileHeader {
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	guint16 magic;
	guint32 file_size;
	guint32 reserved;
	guint32 data_offset;
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};

struct BitmapInfoHeader {
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	guint32 header_size;
	guint32 width;
	guint32 height;
	guint16 planes;
	guint16 bpp;
	guint32 compression;
	guint32 data_size;
	guint32 x_ppm;
	guint32 y_ppm;
	guint32 n_colors;
	guint32 n_important_colors;
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};
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#endif
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/* Compression values */
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#define BI_RGB 0
#define BI_RLE8 1
#define BI_RLE4 2
#define BI_BITFIELDS 3

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/* State machine */
typedef enum {
	READ_STATE_HEADERS,	/* Reading the bitmap file header and bitmap info header */
	READ_STATE_PALETTE,	/* Reading the palette */
	READ_STATE_BITMASKS,	/* Reading the bitmasks for BI_BITFIELDS */
	READ_STATE_DATA,	/* Reading the actual image data */
	READ_STATE_ERROR,	/* An error occurred; further data will be ignored */
	READ_STATE_DONE		/* Done reading the image; further data will be ignored */
} ReadState;
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/*

DumpBIH printf's the values in a BitmapInfoHeader to the screen, for
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debugging purposes.

*/
#if DUMPBIH
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static void DumpBIH(unsigned char *BIH)
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{
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	printf("biSize      = %i \n",
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	       (int) (BIH[3] << 24) + (BIH[2] << 16) + (BIH[1] << 8) +
	       (BIH[0]));
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	printf("biWidth     = %i \n",
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	       (int) (BIH[7] << 24) + (BIH[6] << 16) + (BIH[5] << 8) +
	       (BIH[4]));
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	printf("biHeight    = %i \n",
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	       (int) (BIH[11] << 24) + (BIH[10] << 16) + (BIH[9] << 8) +
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	       (BIH[8]));
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	printf("biPlanes    = %i \n", (int) (BIH[13] << 8) + (BIH[12]));
	printf("biBitCount  = %i \n", (int) (BIH[15] << 8) + (BIH[14]));
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	printf("biCompress  = %i \n",
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	       (int) (BIH[19] << 24) + (BIH[18] << 16) + (BIH[17] << 8) +
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	       (BIH[16]));
	printf("biSizeImage = %i \n",
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	       (int) (BIH[23] << 24) + (BIH[22] << 16) + (BIH[21] << 8) +
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	       (BIH[20]));
	printf("biXPels     = %i \n",
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	       (int) (BIH[27] << 24) + (BIH[26] << 16) + (BIH[25] << 8) +
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	       (BIH[24]));
	printf("biYPels     = %i \n",
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	       (int) (BIH[31] << 24) + (BIH[30] << 16) + (BIH[29] << 8) +
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	       (BIH[28]));
	printf("biClrUsed   = %i \n",
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	       (int) (BIH[35] << 24) + (BIH[34] << 16) + (BIH[33] << 8) +
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	       (BIH[32]));
	printf("biClrImprtnt= %i \n",
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	       (int) (BIH[39] << 24) + (BIH[38] << 16) + (BIH[37] << 8) +
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	       (BIH[36]));
}
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#endif
/* struct headerpair contains the decoded width/height/depth info for
   the current bitmap */
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struct headerpair {
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	guint32 size;
	gint32 width;
	gint32 height;
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	guint depth;
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	guint Negative;		/* Negative = 1 -> top down BMP,
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				   Negative = 0 -> bottom up BMP */
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	guint  n_colors;
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};
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/* Data needed for the "state" during decompression */
struct bmp_compression_state {
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	gint phase;
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	gint run;
	gint count;
	gint x, y;
	guchar *p;
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};
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/* Progressive loading */

struct bmp_progressive_state {
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	GdkPixbufModuleSizeFunc size_func;
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	GdkPixbufModulePreparedFunc prepared_func;
	GdkPixbufModuleUpdatedFunc updated_func;
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	gpointer user_data;

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	ReadState read_state;

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	guint LineWidth;
	guint Lines;		/* # of finished lines */
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	guchar *buff;
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	guint BufferSize;
	guint BufferDone;
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	guchar (*Colormap)[3];
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	gint Type;		/*
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				   32 = RGB + alpha
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				   24 = RGB
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				   16 = RGB
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				   4  = 4 bpp colormapped
				   8  = 8 bpp colormapped
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				   1  = 1 bit bitonal
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				 */
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	guint Compressed;
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	struct bmp_compression_state compr;
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	struct headerpair Header;	/* Decoded (BE->CPU) header */

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	/* Bit masks, shift amounts, and significant bits for BI_BITFIELDS coding */
	int r_mask, r_shift, r_bits;
	int g_mask, g_shift, g_bits;
	int b_mask, b_shift, b_bits;
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	GdkPixbuf *pixbuf;	/* Our "target" */
};

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static gpointer
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gdk_pixbuf__bmp_image_begin_load(GdkPixbufModuleSizeFunc size_func,
                                 GdkPixbufModulePreparedFunc prepared_func,
				 GdkPixbufModuleUpdatedFunc updated_func,
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                                 gpointer user_data,
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                                 GError **error);
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static gboolean gdk_pixbuf__bmp_image_stop_load(gpointer data, GError **error);
static gboolean gdk_pixbuf__bmp_image_load_increment(gpointer data,
                                                     const guchar * buf,
                                                     guint size,
                                                     GError **error);
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/* Picks up a 32-bit little-endian integer starting at the specified location.
 * Does it by hand instead of dereferencing a simple (gint *) cast due to
 * alignment constraints many platforms.
 */
static int
lsb_32 (guchar *src)
{
	return src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
}

/* Same as above, but for 16-bit little-endian integers. */
static short
lsb_16 (guchar *src)
{
	return src[0] | (src[1] << 8);
}

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static gboolean grow_buffer (struct bmp_progressive_state *State,
                             GError **error)
{
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  guchar *tmp;

  if (State->BufferSize == 0) {
    g_set_error (error,
		 GDK_PIXBUF_ERROR,
		 GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
		 _("BMP image has bogus header data"));
    State->read_state = READ_STATE_ERROR;
    return FALSE;
  }

  tmp = g_try_realloc (State->buff, State->BufferSize);

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  if (!tmp) {
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    g_set_error (error,
		 GDK_PIXBUF_ERROR,
		 GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
		 _("Not enough memory to load bitmap image"));
    State->read_state = READ_STATE_ERROR;
    return FALSE;
  }
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  State->buff = tmp;
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  return TRUE;
}

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static gboolean DecodeHeader(unsigned char *BFH, unsigned char *BIH,
                             struct bmp_progressive_state *State,
                             GError **error)
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{
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	gint clrUsed;

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        /* FIXME this is totally unrobust against bogus image data. */
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	if (State->BufferSize < lsb_32 (&BIH[0]) + 14) {
		State->BufferSize = lsb_32 (&BIH[0]) + 14;
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		if (!grow_buffer (State, error))
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			return FALSE;
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		return TRUE;
	}

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#if DUMPBIH
	DumpBIH(BIH);
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#endif    
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	State->Header.size = lsb_32 (&BIH[0]);
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	if (State->Header.size == 108) {
		State->Header.width = lsb_32 (&BIH[4]);
		State->Header.height = lsb_32 (&BIH[8]);
		State->Header.depth = lsb_16 (&BIH[14]);
		State->Compressed = lsb_32 (&BIH[16]);
	} else if (State->Header.size == 40) {
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		State->Header.width = lsb_32 (&BIH[4]);
		State->Header.height = lsb_32 (&BIH[8]);
		State->Header.depth = lsb_16 (&BIH[14]);
		State->Compressed = lsb_32 (&BIH[16]);
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	} else if (State->Header.size == 12) {
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		State->Header.width = lsb_16 (&BIH[4]);
		State->Header.height = lsb_16 (&BIH[6]);
		State->Header.depth = lsb_16 (&BIH[10]);
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		State->Compressed = BI_RGB;
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	} else {
		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("BMP image has unsupported header size"));
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		State->read_state = READ_STATE_ERROR;
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		return FALSE;
	}
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	if (State->Header.size == 12)
		clrUsed = 1 << State->Header.depth;
	else
		clrUsed = (int) (BIH[35] << 24) + (BIH[34] << 16) + (BIH[33] << 8) + (BIH[32]);

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	if (clrUsed != 0)
		State->Header.n_colors = clrUsed;
	else
            State->Header.n_colors = 1 << State->Header.depth;
	
	if (State->Header.n_colors > 1 << State->Header.depth) {
		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("BMP image has bogus header data"));
		State->read_state = READ_STATE_ERROR;
		return FALSE;
	}

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	State->Type = State->Header.depth;	/* This may be less trivial someday */
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	/* Negative heights indicates bottom-down pixelorder */
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	if (State->Header.height < 0) {
		State->Header.height = -State->Header.height;
		State->Header.Negative = 1;
	}
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	if (State->Header.Negative && 
	    (State->Compressed != BI_RGB && State->Compressed != BI_BITFIELDS))
	{
		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("Topdown BMP images cannot be compressed"));
		State->read_state = READ_STATE_ERROR;
		return FALSE;
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	}
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	if (State->Header.width <= 0 || State->Header.height == 0 ||
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	    (State->Compressed == BI_RLE4 && State->Type != 4)    ||
	    (State->Compressed == BI_RLE8 && State->Type != 8)	  ||
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	    (State->Compressed == BI_BITFIELDS && !(State->Type == 16 || State->Type == 32)) ||
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	    (State->Compressed > BI_BITFIELDS)) {
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		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("BMP image has bogus header data"));
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		State->read_state = READ_STATE_ERROR;
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		return FALSE;
	}

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	if (State->Type == 32)
		State->LineWidth = State->Header.width * 4;
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	else if (State->Type == 24)
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		State->LineWidth = State->Header.width * 3;
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	else if (State->Type == 16)
		State->LineWidth = State->Header.width * 2;
	else if (State->Type == 8)
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		State->LineWidth = State->Header.width * 1;
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	else if (State->Type == 4)
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		State->LineWidth = (State->Header.width + 1) / 2;
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	else if (State->Type == 1) {
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		State->LineWidth = State->Header.width / 8;
		if ((State->Header.width & 7) != 0)
			State->LineWidth++;
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	} else {
		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("BMP image has bogus header data"));
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		State->read_state = READ_STATE_ERROR;
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		return FALSE;
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	}
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	/* Pad to a 32 bit boundary */
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	if (((State->LineWidth % 4) > 0)
	    && (State->Compressed == BI_RGB || State->Compressed == BI_BITFIELDS))
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		State->LineWidth = (State->LineWidth / 4) * 4 + 4;

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	if (State->pixbuf == NULL) {
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		if (State->size_func) {
			gint width = State->Header.width;
			gint height = State->Header.height;

			(*State->size_func) (&width, &height, State->user_data);
			if (width == 0 || height == 0) {
				State->read_state = READ_STATE_DONE;
				State->BufferSize = 0;
				return TRUE;
			}
		}

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		if (State->Type == 32 || 
		    State->Compressed == BI_RLE4 || 
		    State->Compressed == BI_RLE8)
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			State->pixbuf =
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				gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8,
					       (gint) State->Header.width,
					       (gint) State->Header.height);
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		else
			State->pixbuf =
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				gdk_pixbuf_new(GDK_COLORSPACE_RGB, FALSE, 8,
					       (gint) State->Header.width,
					       (gint) State->Header.height);
		
		if (State->pixbuf == NULL) {
			g_set_error (error,
				     GDK_PIXBUF_ERROR,
				     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
				     _("Not enough memory to load bitmap image"));
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			State->read_state = READ_STATE_ERROR;
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			return FALSE;
			}
		
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		if (State->prepared_func != NULL)
			/* Notify the client that we are ready to go */
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			(*State->prepared_func) (State->pixbuf, NULL, State->user_data);
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		/* make all pixels initially transparent */
		if (State->Compressed == BI_RLE4 || State->Compressed == BI_RLE8) {
			memset (State->pixbuf->pixels, 0, State->pixbuf->rowstride * State->Header.height);
			State->compr.p = State->pixbuf->pixels 
				+ State->pixbuf->rowstride * (State->Header.height- 1);
		}
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	}
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	State->BufferDone = 0;
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	if (State->Type <= 8) {
		State->read_state = READ_STATE_PALETTE;
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		State->BufferSize = lsb_32 (&BFH[10]) - 14 - State->Header.size; 
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	} else if (State->Compressed == BI_RGB) {
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		if (State->BufferSize < lsb_32 (&BFH[10]))
		{
			/* skip over padding between headers and image data */
			State->read_state = READ_STATE_HEADERS;
			State->BufferDone = State->BufferSize;
			State->BufferSize = lsb_32 (&BFH[10]);
		}
		else
		{
			State->read_state = READ_STATE_DATA;
			State->BufferSize = State->LineWidth;
		}
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	} else if (State->Compressed == BI_BITFIELDS) {
		State->read_state = READ_STATE_BITMASKS;
		State->BufferSize = 12;
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	} else {
		g_set_error (error,
			     GDK_PIXBUF_ERROR,
			     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
			     _("BMP image has bogus header data"));
		State->read_state = READ_STATE_ERROR;
		return FALSE;
	}
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	if (!grow_buffer (State, error)) 
		return FALSE;
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        return TRUE;
}

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static gboolean DecodeColormap (guchar *buff,
				struct bmp_progressive_state *State,
				GError **error)
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{
	gint i;
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	gint samples;
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	g_assert (State->read_state == READ_STATE_PALETTE);

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	samples = (State->Header.size == 12 ? 3 : 4);
	if (State->BufferSize < State->Header.n_colors * samples) {
		State->BufferSize = State->Header.n_colors * samples;
		if (!grow_buffer (State, error))
			return FALSE;
		return TRUE;
	}

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	State->Colormap = g_malloc0 ((1 << State->Header.depth) * sizeof (*State->Colormap));
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	for (i = 0; i < State->Header.n_colors; i++)
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	{
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		State->Colormap[i][0] = buff[i * samples];
		State->Colormap[i][1] = buff[i * samples + 1];
		State->Colormap[i][2] = buff[i * samples + 2];
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#ifdef DUMPCMAP
		g_print ("color %d %x %x %x\n", i,
			 State->Colormap[i][0],
			 State->Colormap[i][1],
			 State->Colormap[i][2]);
#endif
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	}

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	State->read_state = READ_STATE_DATA;

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	State->BufferDone = 0;
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	if (!(State->Compressed == BI_RGB || State->Compressed == BI_BITFIELDS))
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		State->BufferSize = 2;
	else
		State->BufferSize = State->LineWidth;
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	if (!grow_buffer (State, error))
		return FALSE;
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	return TRUE;
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}

/* Finds the lowest set bit and the number of set bits */
static void
find_bits (int n, int *lowest, int *n_set)
{
	int i;

	*n_set = 0;

	for (i = 31; i >= 0; i--)
		if (n & (1 << i)) {
			*lowest = i;
			(*n_set)++;
		}
}

/* Decodes the 3 shorts that follow for the bitmasks for BI_BITFIELDS coding */
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static gboolean
decode_bitmasks (guchar *buf,
		 struct bmp_progressive_state *State, 
		 GError **error)
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{
	State->r_mask = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
	buf += 4;

	State->g_mask = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
	buf += 4;

	State->b_mask = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);

	find_bits (State->r_mask, &State->r_shift, &State->r_bits);
	find_bits (State->g_mask, &State->g_shift, &State->g_bits);
	find_bits (State->b_mask, &State->b_shift, &State->b_bits);

	if (State->r_bits == 0 || State->g_bits == 0 || State->b_bits == 0) {
		State->r_mask = 0x7c00;
		State->r_shift = 10;
		State->g_mask = 0x03e0;
		State->g_shift = 5;
		State->b_mask = 0x001f;
		State->b_shift = 0;

		State->r_bits = State->g_bits = State->b_bits = 5;
	}

	State->read_state = READ_STATE_DATA;
	State->BufferDone = 0;
	State->BufferSize = State->LineWidth;
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	if (!grow_buffer (State, error)) 
		return FALSE;

	return TRUE;
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}

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/*
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 * func - called when we have pixmap created (but no image data)
 * user_data - passed as arg 1 to func
 * return context (opaque to user)
 */

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static gpointer
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gdk_pixbuf__bmp_image_begin_load(GdkPixbufModuleSizeFunc size_func,
                                 GdkPixbufModulePreparedFunc prepared_func,
				 GdkPixbufModuleUpdatedFunc updated_func,
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                                 gpointer user_data,
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                                 GError **error)
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{
	struct bmp_progressive_state *context;
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	context = g_new0(struct bmp_progressive_state, 1);
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	context->size_func = size_func;
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	context->prepared_func = prepared_func;
	context->updated_func = updated_func;
	context->user_data = user_data;

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	context->read_state = READ_STATE_HEADERS;

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	context->BufferSize = 26;
	context->buff = g_malloc(26);
	context->BufferDone = 0;
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	/* 14 for the BitmapFileHeader, 12 for the BitmapImageHeader */
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	context->Colormap = NULL;
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	context->Lines = 0;

	context->Type = 0;

	memset(&context->Header, 0, sizeof(struct headerpair));
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	memset(&context->compr, 0, sizeof(struct bmp_compression_state));
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	context->pixbuf = NULL;
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	return (gpointer) context;
}

/*
 * context - returned from image_begin_load
 *
 * free context, unref gdk_pixbuf
 */
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static gboolean gdk_pixbuf__bmp_image_stop_load(gpointer data, GError **error)
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{
	struct bmp_progressive_state *context =
	    (struct bmp_progressive_state *) data;

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        /* FIXME this thing needs to report errors if
         * we have unused image data
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         */
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	g_return_val_if_fail(context != NULL, TRUE);
610

611 612
	if (context->Colormap != NULL)
		g_free(context->Colormap);
613 614

	if (context->pixbuf)
615
		g_object_unref(context->pixbuf);
616

617
	g_free(context->buff);
618
	g_free(context);
619 620

        return TRUE;
621 622 623
}


624 625 626 627 628 629
/*
The OneLineXX functions are called when 1 line worth of data is present.
OneLine24 is the 24 bpp-version.
*/
static void OneLine32(struct bmp_progressive_state *context)
{
630
	int i;
631 632
	guchar *pixels;
	guchar *src;
633

634 635 636
	if (!context->Header.Negative)
		pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride * (context->Header.height - context->Lines - 1));
637
	else
638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654
		pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride * context->Lines);

	src = context->buff;

	if (context->Compressed == BI_BITFIELDS) {
		int r_lshift, r_rshift;
		int g_lshift, g_rshift;
		int b_lshift, b_rshift;

		r_lshift = 8 - context->r_bits;
		g_lshift = 8 - context->g_bits;
		b_lshift = 8 - context->b_bits;

		r_rshift = context->r_bits - r_lshift;
		g_rshift = context->g_bits - g_lshift;
		b_rshift = context->b_bits - b_lshift;
655

656 657 658 659 660 661 662 663 664 665 666 667
		for (i = 0; i < context->Header.width; i++) {
			int v, r, g, b;

			v = src[0] | (src[1] << 8) | (src[2] << 16);

			r = (v & context->r_mask) >> context->r_shift;
			g = (v & context->g_mask) >> context->g_shift;
			b = (v & context->b_mask) >> context->b_shift;

			*pixels++ = (r << r_lshift) | (r >> r_rshift);
			*pixels++ = (g << g_lshift) | (g >> g_rshift);
			*pixels++ = (b << b_lshift) | (b >> b_rshift);
668
			*pixels++ = 0xff;
669 670 671 672 673 674 675 676

			src += 4;
		}
	} else
		for (i = 0; i < context->Header.width; i++) {
			*pixels++ = src[2];
			*pixels++ = src[1];
			*pixels++ = src[0];
677
			*pixels++ = 0xff;
678 679 680

			src += 4;
		}
681 682
}

683 684 685 686 687 688
static void OneLine24(struct bmp_progressive_state *context)
{
	gint X;
	guchar *Pixels;

	X = 0;
689
	if (context->Header.Negative == 0)
690 691 692
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  (context->Header.height - context->Lines - 1));
693
	else
694 695 696
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  context->Lines);
697
	while (X < context->Header.width) {
698 699 700
		Pixels[X * 3 + 0] = context->buff[X * 3 + 2];
		Pixels[X * 3 + 1] = context->buff[X * 3 + 1];
		Pixels[X * 3 + 2] = context->buff[X * 3 + 0];
701 702 703 704 705
		X++;
	}

}

706 707
static void OneLine16(struct bmp_progressive_state *context)
{
708 709 710
	int i;
	guchar *pixels;
	guchar *src;
711

712 713 714
	if (!context->Header.Negative)
		pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride * (context->Header.height - context->Lines - 1));
715
	else
716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761
		pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride * context->Lines);

	src = context->buff;

	if (context->Compressed == BI_BITFIELDS) {
		int r_lshift, r_rshift;
		int g_lshift, g_rshift;
		int b_lshift, b_rshift;

		r_lshift = 8 - context->r_bits;
		g_lshift = 8 - context->g_bits;
		b_lshift = 8 - context->b_bits;

		r_rshift = context->r_bits - r_lshift;
		g_rshift = context->g_bits - g_lshift;
		b_rshift = context->b_bits - b_lshift;

		for (i = 0; i < context->Header.width; i++) {
			int v, r, g, b;

			v = (int) src[0] | ((int) src[1] << 8);

			r = (v & context->r_mask) >> context->r_shift;
			g = (v & context->g_mask) >> context->g_shift;
			b = (v & context->b_mask) >> context->b_shift;

			*pixels++ = (r << r_lshift) | (r >> r_rshift);
			*pixels++ = (g << g_lshift) | (g >> g_rshift);
			*pixels++ = (b << b_lshift) | (b >> b_rshift);

			src += 2;
		}
	} else
		for (i = 0; i < context->Header.width; i++) {
			int v, r, g, b;

			v = src[0] | (src[1] << 8);

			r = (v >> 10) & 0x1f;
			g = (v >> 5) & 0x1f;
			b = v & 0x1f;

			*pixels++ = (r << 3) | (r >> 2);
			*pixels++ = (g << 3) | (g >> 2);
			*pixels++ = (b << 3) | (b >> 2);
762 763

			src += 2;
764
		}
765 766
}

767 768 769 770 771 772
static void OneLine8(struct bmp_progressive_state *context)
{
	gint X;
	guchar *Pixels;

	X = 0;
773
	if (context->Header.Negative == 0)
774 775 776
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  (context->Header.height - context->Lines - 1));
777
	else
778 779 780
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  context->Lines);
781 782
	while (X < context->Header.width) {
		Pixels[X * 3 + 0] =
783
		    context->Colormap[context->buff[X]][2];
784
		Pixels[X * 3 + 1] =
785
		    context->Colormap[context->buff[X]][1];
786
		Pixels[X * 3 + 2] =
787
		    context->Colormap[context->buff[X]][0];
788 789 790 791
		X++;
	}
}

792 793 794 795 796 797 798
static void OneLine4(struct bmp_progressive_state *context)
{
	gint X;
	guchar *Pixels;

	X = 0;
	if (context->Header.Negative == 0)
799 800 801
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  (context->Header.height - context->Lines - 1));
802
	else
803 804 805
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  context->Lines);
806 807 808 809

	while (X < context->Header.width) {
		guchar Pix;

810
		Pix = context->buff[X / 2];
811 812

		Pixels[X * 3 + 0] =
813
		    context->Colormap[Pix >> 4][2];
814
		Pixels[X * 3 + 1] =
815
		    context->Colormap[Pix >> 4][1];
816
		Pixels[X * 3 + 2] =
817
		    context->Colormap[Pix >> 4][0];
818 819 820 821
		X++;
		if (X < context->Header.width) {
			/* Handle the other 4 bit pixel only when there is one */
			Pixels[X * 3 + 0] =
822
			    context->Colormap[Pix & 15][2];
823
			Pixels[X * 3 + 1] =
824
			    context->Colormap[Pix & 15][1];
825
			Pixels[X * 3 + 2] =
826
			    context->Colormap[Pix & 15][0];
827 828 829 830 831 832
			X++;
		}
	}

}

833 834 835 836 837 838
static void OneLine1(struct bmp_progressive_state *context)
{
	gint X;
	guchar *Pixels;

	X = 0;
839
	if (context->Header.Negative == 0)
840 841 842
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  (context->Header.height - context->Lines - 1));
843
	else
844 845 846
		Pixels = (context->pixbuf->pixels +
			  context->pixbuf->rowstride *
			  context->Lines);
847
	while (X < context->Header.width) {
848
		gint Bit;
849

850
		Bit = (context->buff[X / 8]) >> (7 - (X & 7));
851
		Bit = Bit & 1;
852 853 854
		Pixels[X * 3 + 0] = context->Colormap[Bit][2];
		Pixels[X * 3 + 1] = context->Colormap[Bit][1];
		Pixels[X * 3 + 2] = context->Colormap[Bit][0];
855 856 857 858 859 860 861
		X++;
	}
}


static void OneLine(struct bmp_progressive_state *context)
{
862
	context->BufferDone = 0;
863 864 865
	if (context->Lines >= context->Header.height)
		return;

866 867
	if (context->Type == 32)
		OneLine32(context);
868
	else if (context->Type == 24)
869
		OneLine24(context);
870
	else if (context->Type == 16)
871
		OneLine16(context);
872
	else if (context->Type == 8)
873
		OneLine8(context);
874
	else if (context->Type == 4)
875
		OneLine4(context);
876
	else if (context->Type == 1)
877
		OneLine1(context);
878 879
	else
		g_assert_not_reached ();
880 881 882 883 884 885

	context->Lines++;

	if (context->updated_func != NULL) {
		(*context->updated_func) (context->pixbuf,
					  0,
886 887 888
					  (context->Header.Negative ?
					   (context->Lines - 1) :
					   (context->Header.height - context->Lines)),
889
					  context->Header.width,
890
					  1,
891
					  context->user_data);
892 893 894 895

	}
}

896 897 898 899 900 901 902 903 904 905 906 907 908 909
#define NEUTRAL       0
#define ENCODED       1
#define ESCAPE        2   
#define DELTA_X       3
#define DELTA_Y       4
#define ABSOLUTE      5
#define SKIP          6

#define END_OF_LINE   0
#define END_OF_BITMAP 1
#define DELTA         2

static gboolean 
DoCompressed(struct bmp_progressive_state *context, GError **error)
910
{
911 912 913 914 915
	gint i, j;
	gint y;
	guchar c;
	gint idx;

916 917 918 919 920 921