Geografic-Information-System/raster/r.compress/main.c

/****************************************************************************
 *
 * MODULE:       r.compress
 *
 * AUTHOR(S):    James Westervelt - CERL
 *               Michael Shapiro - CERL
 *
 * PURPOSE:      Compress and decompress raster map files.
 *
 * COPYRIGHT:    (C) 2003 by the GRASS Development Team
 *
 *               This program is free software under the GNU General Public
 *               License (>=v2). Read the file COPYING that comes with GRASS
 *               for details.
 *
 ***************************************************************************/

/****************************************************************************
 * compress_cell converts straight grid_cell files into compressed grid_cell
 * files.  Compressed files have the following format:
 *
 *  - Array of addresses pointing to the internal start of each row
 *    First byte of each row is the nuber of bytes per cell for that row
 *    Remainder of the row is a series of byte groups that describe the data:
 *        First byte: number of cells that contain the category given by second
 *        Next byte(s): category number. The number of bytes is determined
 *                      by the number of bytes in a cell 
 *
 * The normal G_open_cell(), and Rast_put_row() do the compression
 * This program must only check that the file is not a reclass file and
 * is not already compressed.
 *
 * The only trick is to preserve the support files
 *
 *****************************************************************************/

#include <stdlib.h>
#include <limits.h>
#include <sys/types.h>
#include <unistd.h>
#include <grass/gis.h>
#include <grass/raster.h>
#include <grass/glocale.h>

static off_t newsize, oldsize;
static int process(char *, int);
static int doit(char *, int, RASTER_MAP_TYPE);

int main(int argc, char *argv[])
{
    int stat;
    int n;
    char *name;
    struct GModule *module;
    struct Option *map;
    struct Flag *uncompress;

    G_gisinit(argv[0]);

    module = G_define_module();
    G_add_keyword(_("raster"));
    G_add_keyword(_("map management"));
    module->description = _("Compresses and decompresses raster maps.");

    map = G_define_option();
    map->key = "map";
    map->type = TYPE_STRING;
    map->required = YES;
    map->gisprompt = "old,cell,raster";
    map->multiple = YES;
    map->description = _("Name of existing raster map(s)");

    uncompress = G_define_flag();
    uncompress->key = 'u';
    uncompress->description = _("Uncompress the map");

    if (G_parser(argc, argv))
	exit(EXIT_FAILURE);

    stat = 0;
    for (n = 0; (name = map->answers[n]); n++)
	if (process(name, uncompress->answer))
	    stat = 1;
    exit(stat);
}


static int process(char *name, int uncompress)
{
    struct Colors colr;
    struct History hist;
    struct Categories cats;
    struct Quant quant;
    int colr_ok;
    int hist_ok;
    int cats_ok;
    int quant_ok;
    off_t diff;
    RASTER_MAP_TYPE map_type;
    char rname[GNAME_MAX], rmapset[GMAPSET_MAX];

    if (G_find_raster(name, G_mapset()) == NULL) {
	G_warning(_("[%s] not found"), name);
	return 1;
    }
    if (Rast_is_reclass(name, G_mapset(), rname, rmapset) > 0) {
	G_warning(uncompress
		  ?
		  _("[%s] is a reclass file of map <%s> in mapset <%s> - can't uncompress")
		  :
		  _("[%s] is a reclass file of map <%s> in mapset <%s> - can't compress"),
		  name, rname, rmapset);
	return 1;
    }
    if (G_find_file2_misc("cell_misc", "gdal", name, G_mapset())) {
	G_warning(_("[%s] is a GDAL-linked map - can't (un)compress"), name);
	return 1;
    }

    map_type = Rast_map_type(name, G_mapset());

    G_suppress_warnings(1);
    colr_ok = Rast_read_colors(name, G_mapset(), &colr) > 0;
    hist_ok = Rast_read_history(name, G_mapset(), &hist) >= 0;
    cats_ok = Rast_read_cats(name, G_mapset(), &cats) >= 0;

    if (map_type != CELL_TYPE) {
	Rast_quant_init(&quant);
	quant_ok = Rast_read_quant(name, G_mapset(), &quant);
	G_suppress_warnings(0);
    }

    if (doit(name, uncompress, map_type))
	return 1;

    if (colr_ok) {
	Rast_write_colors(name, G_mapset(), &colr);
	Rast_free_colors(&colr);
    }
    if (hist_ok)
	Rast_write_history(name, &hist);
    if (cats_ok) {
	cats.num = Rast_get_max_c_cat(name, G_mapset());
	Rast_write_cats(name, &cats);
	Rast_free_cats(&cats);
    }
    if (map_type != CELL_TYPE && quant_ok)
	Rast_write_quant(name, G_mapset(), &quant);

    diff = newsize - oldsize;
    if (diff < 0)
	diff = -diff;
    if (sizeof(off_t) > sizeof(long) && diff > ULONG_MAX)
	diff = ULONG_MAX;

    if (newsize < oldsize)
	G_message(uncompress
		  ? _("DONE: uncompressed file is %lu bytes smaller")
		  : _("DONE: compressed file is %lu bytes smaller"),
		  (unsigned long)diff);
    else if (newsize > oldsize)
	G_message(uncompress
		  ? _("DONE: uncompressed file is %lu bytes bigger")
		  : _("DONE: compressed file is %lu bytes bigger"),
		  (unsigned long)diff);
    else
	G_message("same size");

    return 0;
}

static int doit(char *name, int uncompress, RASTER_MAP_TYPE map_type)
{
    struct Cell_head cellhd;
    int new, old, nrows, row;
    void *rast;

    Rast_get_cellhd(name, G_mapset(), &cellhd);

    /* check if already compressed/decompressed */
    if (uncompress && cellhd.compressed == 0) {
	G_warning(_("[%s] already uncompressed"), name);
	return 1;
    }
    else if (!uncompress && cellhd.compressed > 0) {
	G_warning(_("[%s] already compressed"), name);
	return 1;
    }

    G_message(_("\n%sCOMPRESS [%s]"), uncompress ? "UN" : "", name);

    Rast_set_window(&cellhd);

    old = Rast_open_old(name, G_mapset());

    if (uncompress) {
	if (map_type == CELL_TYPE) {
	    Rast_set_cell_format(cellhd.format);
	    new = Rast_open_c_new_uncompressed(name);
	}
	else {
	    Rast_set_fp_type(map_type);
	    new = Rast_open_fp_new_uncompressed(name);
	}
    }
    else
	new = Rast_open_new(name, map_type);

    nrows = Rast_window_rows();
    rast = Rast_allocate_buf(map_type);

    oldsize = lseek(old, (off_t) 0, SEEK_END);

    /* the null file is written automatically */
    for (row = 0; row < nrows; row++) {
	G_percent(row, nrows, 2);
	Rast_get_row_nomask(old, rast, row, map_type);
	Rast_put_row(new, rast, map_type);
    }
    G_free(rast);
    Rast_close(old);
    if (row < nrows) {
	Rast_unopen(new);
	return 1;
    }
    Rast_close(new);
    newsize = 0;
    old = Rast_open_old(name, G_mapset());
    newsize = lseek(old, (off_t) 0, SEEK_END);
    Rast_close(old);
    return 0;
}