1 files changed, 208 insertions, 0 deletions
diff --git a/converter/pgm/sbigtopgm.c b/converter/pgm/sbigtopgm.c
new file mode 100644
index 00000000..bb3cb6fe
--- /dev/null
+++ b/converter/pgm/sbigtopgm.c
@@ -0,0 +1,208 @@
+/*
+
+    sbigtopgm.c - read a Santa Barbara Instruments Group CCDOPS file
+
+    Note: All SBIG CCD astronomical cameras produce 14 bits or
+	  (the ST-4 and ST-5) or 16 bits (ST-6 and later) per pixel.
+
+		  Copyright (C) 1998 by John Walker
+		       http://www.fourmilab.ch/
+
+    If you find yourself having to add functionality included subsequent
+    to the implementation of this program, you can probably find
+    documentation of any changes to the SBIG file format on their
+    Web site: http://www.sbig.com/
+
+    Permission to use, copy, modify, and distribute this software and
+    its documentation for any purpose and without fee is hereby
+    granted, provided that the above copyright notice appear in all
+    copies and that both that copyright notice and this permission
+    notice appear in supporting documentation.	This software is
+    provided "as is" without express or implied warranty.
+
+*/
+
+#include <string.h>
+
+#include "pgm.h"
+#include "nstring.h"
+
+#define SBIG_HEADER_LENGTH  2048      /* File header length */
+
+/*  looseCanon	--  Canonicalize a line from the file header so
+		    items more sloppily formatted than those
+		    written by CCDOPS are still accepted.  */
+
+static void looseCanon(cp)
+  char *cp;
+{
+    char *op = cp;
+    char c;
+    
+    while ((c = *cp++) != 0) {
+	if (!ISSPACE(c)) {
+	    if (ISUPPER(c)) {
+		c = tolower(c);
+	    }
+	    *op++ = c;
+	}
+    }
+    *op++ = 0;
+}
+
+int main(argc, argv)
+  int argc;
+  char* argv[];
+{
+    FILE *ifp;
+    gray *grayrow;
+    register gray *gP;
+    int argn, row;
+    register int col;
+    int maxval;
+    int comp, rows, cols;
+    char header[SBIG_HEADER_LENGTH];
+    char *hdr;
+    static char camera[80] = "ST-?";
+
+    pgm_init(&argc, argv);
+
+    argn = 1;
+
+    if (argn < argc) {
+	ifp = pm_openr(argv[argn]);
+	argn++;
+    } else {
+	ifp = stdin;
+    }
+
+    if (argn != argc)
+        pm_usage( "[sbigfile]" );
+
+    if (fread(header, SBIG_HEADER_LENGTH, 1, ifp) < 1) {
+        pm_error("error reading SBIG file header");
+    }
+
+    /*	Walk through the header and parse relevant parameters.	*/
+
+    comp = -1;
+    cols = -1;
+    rows = -1;
+
+    /*	The SBIG header specification equivalent to maxval is
+        "Sat_level", the saturation level of the image.  This
+	specification is optional, and was not included in files
+	written by early versions of CCDOPS. It was introduced when it
+	became necessary to distinguish 14-bit images with a Sat_level
+	of 16383 from 16-bit images which saturate at 65535.  In
+	addition, co-adding images or capturing with Track and
+	Accumulate can increase the saturation level.  Since files
+        which don't have a Sat_level line in the header were most
+	probably written by early drivers for the ST-4 or ST-5, it
+	might seem reasonable to make the default for maxval 16383,
+	the correct value for those cameras.  I chose instead to use
+	65535 as the default because the overwhelming majority of
+        cameras in use today are 16 bit, and it's possible some
+        non-SBIG software may omit the "optional" Sat_level
+	specification.	Also, no harm is done if a larger maxval is
+	specified than appears in the image--a simple contrast stretch
+	will adjust pixels to use the full 0 to maxval range.  The
+	converse, pixels having values greater than maxval, results in
+	an invalid file which may cause problems in programs which
+	attempt to process it.	*/
+
+    maxval = 65535;
+
+    hdr = header;
+
+    for (;;) {
+        char *cp = strchr(hdr, '\n');
+
+	if (cp == NULL) {
+            pm_error("malformed SBIG file header at character %d", hdr - header);
+	}
+	*cp = 0;
+        if (strncmp(hdr, "ST-", 3) == 0) {
+            char *ep = strchr(hdr + 3, ' ');
+
+	    if (ep != NULL) {
+		*ep = 0;
+		strcpy(camera, hdr);
+                *ep = ' ';
+	    }
+	}
+	looseCanon(hdr);
+        if (strncmp(hdr, "st-", 3) == 0) {
+            comp = strstr(hdr, "compressed") != NULL;
+        } else if (strncmp(hdr, "height=", 7) == 0) {
+	    rows = atoi(hdr + 7);
+        } else if (strncmp(hdr, "width=", 6) == 0) {
+	    cols = atoi(hdr + 6);
+        } else if (strncmp(hdr, "sat_level=", 10) == 0) {
+	    maxval = atoi(hdr + 10);
+        } else if (STREQ(hdr, "end")) {
+	    break;
+	}
+	hdr = cp + 1;
+    }
+
+    if ((comp == -1) || (rows == -1) || (cols == -1)) {
+        pm_error("required specification missing from SBIG file header");
+    }
+
+    fprintf(stderr, "SBIG %s %dx%d %s image, saturation level = %d.\n",
+        camera, cols, rows, comp ? "compressed" : "uncompressed", maxval);
+
+    if (maxval > PGM_OVERALLMAXVAL) {
+        pm_error("Saturation level (%d levels) is too large.\n"
+                 "This program's limit is %d.", maxval, PGM_OVERALLMAXVAL);
+    }
+
+    pgm_writepgminit(stdout, cols, rows, (gray) maxval, 0);
+    grayrow = pgm_allocrow(cols);
+
+#define DOSINT(fp) ((getc(fp) & 0xFF) | (getc(fp) << 8))
+
+    for (row = 0; row < rows; row++) {
+	int compthis = comp;
+
+	if (comp) {
+	    int rowlen = DOSINT(ifp); /* Compressed row length */
+
+	    /*	If compression results in a row length >= the uncompressed
+		row length, that row is output uncompressed.  We detect this
+		by observing that the compressed row length is equal to
+		that of an uncompressed row.  */
+
+	    if (rowlen == cols * 2) {
+		compthis = 0;
+	    }
+	}
+	for (col = 0, gP = grayrow; col < cols; col++, gP++) {
+	    gray g;
+
+	    if (compthis) {
+
+		if (col == 0) {
+		    g = DOSINT(ifp);
+		} else {
+		    int delta = getc(ifp);
+
+		    if (delta == 0x80) {
+			g = DOSINT(ifp);
+		    } else {
+			g += ((signed char) delta);
+		    }
+		}
+	    } else {
+		g = DOSINT(ifp);
+	    }
+	    *gP = g;
+	}
+	pgm_writepgmrow(stdout, grayrow, cols, (gray) maxval, 0);
+    }
+    pm_close(ifp);
+    pm_close(stdout);
+
+    return 0;
+}