added trivial support for DEM subfile

Makefile

@@ -1,6 +1,6 @@
 CC = gcc
 CFLAGS = -Wall -D_FILE_OFFSET_BITS=64
-GIMGLIB_SOURCES = gimglib.c util.c sf_typ.c sf_mps.c sf_tre.c sf_rgn.c sf_lbl.c sf_net.c sf_nod.c sf_gmp.c
+GIMGLIB_SOURCES = gimglib.c util.c sf_typ.c sf_mps.c sf_tre.c sf_rgn.c sf_lbl.c sf_net.c sf_nod.c sf_dem.c sf_gmp.c
 GIMGLIB_OBJS = $(GIMGLIB_SOURCES:.c=.o)
 
 all: gimginfo gimgfixcmd gimgxor gimgunlock gimgch gimgextract cmdc

garmin_struct.h

@@ -374,6 +374,18 @@ struct garmin_nod
 	uint32_t unknown_07b;        // 0x7b
 } PACK_STRUCT ;
 
+struct garmin_dem
+{
+	struct garmin_subfile comm;
+	uint32_t flags;             // 0x015
+	uint16_t zoom_levels;       // 0x019
+	uint32_t reserved0;         // 0x01B
+	uint16_t record_size;       // 0x01F
+	uint32_t points_to_block3;  // 0x021
+	// This may not be present on every map:
+	uint32_t reserved2;         // 0x025
+} PACK_STRUCT ;
+
 struct garmin_gmp {
 	struct garmin_subfile comm;
 	uint32_t unknown_015;
@@ -382,7 +394,7 @@ struct garmin_gmp {
 	uint32_t lbl_offset;
 	uint32_t net_offset;
 	uint32_t nod_offset;
-	uint32_t unknown_02d;
+	uint32_t dem_offset;
 } PACK_STRUCT ;
 
 /* http://ati.land.cz/ */

gimglib.c

@@ -155,7 +155,7 @@ static int parse_img (struct gimg_struct *img)
 				int k;
 
 				//vlog("fat%d: gmp 0x%x+0x%x\n", i, fat->blocks[0] * block_size, fat->size);
-				for (k = 0; k < 5; k ++) { // k matches ST_TRE to ST_NOD
+				for (k = 0; k < NUMBER_SUBFILES; k ++) { // k matches ST_TRE to ST_NOD
 					uint32_t abs_offset, rel_offset = *(&gmp->tre_offset + k);
 					if (rel_offset == 0) {
 						//vlog("GMP has no %s\n", get_subtype_name(k));
@@ -266,7 +266,7 @@ static int parse_img (struct gimg_struct *img)
 				orphans_tail = orphans_tail->orphan_next = subfile;
 		} else {
 			switch (subfile->typeid) {
-			case ST_TRE: case ST_RGN: case ST_LBL: case ST_NET: case ST_NOD:
+			case ST_TRE: case ST_RGN: case ST_LBL: case ST_NET: case ST_NOD: case ST_DEM:
 				if (submap->subfiles[subfile->typeid])
 					fprintf(stderr, "Warning: file %s has duplicate %s\n", subfile->name, subfile->type);
 				submap->subfiles[subfile->typeid] = subfile;
@@ -368,7 +368,7 @@ void dump_img (struct gimg_struct *img)
 					submap->name,
 					submap->gmp->offset,
 					submap->gmp->size);
-			for (k = 0; k <= ST_NOD; k ++) {
+			for (k = 0; k < NUMBER_SUBFILES; k ++) {
 				if (submap->subfiles[k])
 					printf(" %s abs=0x%x rel=0x%x\n",
 							get_subtype_name(k),
@@ -380,7 +380,7 @@ void dump_img (struct gimg_struct *img)
 		} else { // OF
 			int k;
 			printf("%s: OF\n", submap->name);
-			for (k = 0; k <= ST_NOD; k ++) {
+			for (k = 0; k <  NUMBER_SUBFILES; k ++) {
 				if (submap->subfiles[k])
 					printf(" %s off=0x%x size=0x%x\n",
 							get_subtype_name(k),
@@ -425,6 +425,7 @@ void dump_subfile (struct gimg_struct *img, const char *subfile_name)
 		case ST_LBL: dump_lbl(subfile); break;
 		case ST_NET: dump_net(subfile); break;
 		case ST_NOD: dump_nod(subfile); break;
+		case ST_DEM: dump_dem(subfile); break;
 		case ST_TYP: dump_typ(subfile); break;
 		case ST_MPS: dump_mps(subfile); break;
 		case ST_GMP: dump_gmp(subfile); break;

gimglib.h

@@ -28,9 +28,10 @@
 #endif
 
 #include "garmin_struct.h"
+#define NUMBER_SUBFILES 6
 
 enum subtype {
-	ST_TRE, ST_RGN, ST_LBL, ST_NET, ST_NOD, // these 5 should match the GMP header
+	ST_TRE, ST_RGN, ST_LBL, ST_NET, ST_NOD, ST_DEM, // these 6 should match the GMP header
 	ST_SRT,
 	ST_GMP,
 	ST_TYP, ST_MDR, ST_TRF, ST_MPS, ST_QSI,
@@ -55,13 +56,14 @@ struct subfile_struct {
 struct submap_struct {
 	char name[9];
 	union {
-		struct subfile_struct *subfiles[5];
+		struct subfile_struct *subfiles[NUMBER_SUBFILES];
 		struct {
 			struct subfile_struct *tre; // always set.
 			struct subfile_struct *rgn;
 			struct subfile_struct *lbl;
 			struct subfile_struct *net;
 			struct subfile_struct *nod;
+			struct subfile_struct *dem;
 		};
 	};
 	struct subfile_struct *srt;
@@ -121,6 +123,9 @@ void dump_net (struct subfile_struct *sf);
 /* sf_nod.c */
 void dump_nod (struct subfile_struct *sf);
 
+/* sf_dem.c */
+void dump_dem (struct subfile_struct *sf);
+
 /* sf_gmp.c */
 void dump_gmp (struct subfile_struct *sf);
 

sf_dem.c

@@ -0,0 +1,26 @@
+#include "gimglib.h"
+
+void dump_dem (struct subfile_struct *sf)
+{
+	struct garmin_dem *header = (struct garmin_gmp *)sf->header;
+
+	assert(sf->typeid == ST_DEM);
+
+	dump_comm(sf->header);
+
+	printf("=== DEM HEADER ===\n");
+	printf("Flags:             0x%x\n", header->flags);
+	printf("Zoom Levels:       0x%x\n", header->zoom_levels);
+	printf("Reserved:          0x%x\n", header->reserved0);
+	printf("Record Size:       0x%x\n", header->record_size);
+	printf("Points to Block 3: 0x%x\n", header->points_to_block3);
+	printf("Reserved:          0x%x\n", header->reserved2);
+
+	if (header->comm.hlen > sizeof(struct garmin_gmp))
+		printf("from 0x%lx to 0x%x (0x%lx bytes): %s\n",
+				sizeof(struct garmin_gmp), header->comm.hlen - 1,
+				header->comm.hlen - sizeof(struct garmin_gmp),
+				dump_unknown_bytes((uint8_t *)header + sizeof(struct garmin_gmp), header->comm.hlen - sizeof(struct garmin_gmp)));
+
+	return;
+}

sf_gmp.c

@@ -15,7 +15,7 @@ void dump_gmp (struct subfile_struct *sf)
 	printf("LBL Offset:  0x%x\n", header->lbl_offset);
 	printf("NET Offset:  0x%x\n", header->net_offset);
 	printf("NOD Offset:  0x%x\n", header->nod_offset);
-	printf("unknown_02d: 0x%x\n", header->unknown_02d);
+	printf("DEM Offset:  0x%x\n", header->dem_offset);
 
 	if (header->comm.hlen > sizeof(struct garmin_gmp))
 		printf("from 0x%lx to 0x%x (0x%lx bytes): %s\n",

util.c

@@ -104,6 +104,7 @@ enum subtype get_subtype_id (const char *str) // only use 3 chars from str
 	if (memcmp(str, "LBL", 3) == 0) return ST_LBL;
 	if (memcmp(str, "NET", 3) == 0) return ST_NET;
 	if (memcmp(str, "NOD", 3) == 0) return ST_NOD;
+	if (memcmp(str, "DEM", 3) == 0) return ST_DEM;
 	if (memcmp(str, "SRT", 3) == 0) return ST_SRT;
 	if (memcmp(str, "GMP", 3) == 0) return ST_GMP;
 	if (memcmp(str, "TYP", 3) == 0) return ST_TYP;
@@ -117,7 +118,7 @@ enum subtype get_subtype_id (const char *str) // only use 3 chars from str
 const char *get_subtype_name (enum subtype id)
 {
 	const static char *type_names[] = {
-		"TRE", "RGN", "LBL", "NET", "NOD",
+		"TRE", "RGN", "LBL", "NET", "NOD", "DEM",
 		"SRT", "GMP", "TYP", "MDR", "TRF",
 		"MPS", "QSI"};
 	return id >= ST_UNKNOWN ? NULL : type_names[id];