Cleanup: move parse_location() declaration into header file

The parse_location() function was used in three places. In two
of them, the declaration was in the translation unit. Instead,
move the declaration into a header file, to avoid duplication
and the possibility of inconsistencies.

The "units.h" header was chosen as this is where location_t
is defined.

Moreover, make the string argument to parse_location() "const
char *", so that it can be used on non-owned buffers.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/libdivecomputer.c

@@ -570,8 +570,6 @@ static void set_dc_serial(struct divecomputer *dc, const char *serial)
 		dc->deviceid = calculate_string_hash(serial);
 }
 
-extern void parse_location(char *, location_t *);
-
 static void parse_string_field(device_data_t *devdata, struct dive *dive, dc_field_string_t *str)
 {
 	// Our dive ID is the string hash of the "Dive ID" string

core/load-git.c

@@ -31,7 +31,6 @@ struct keyword_action {
 };
 #define ARRAY_SIZE(array) (sizeof(array)/sizeof(array[0]))
 
-extern void parse_location(char *buf, location_t *);
 git_blob *git_tree_entry_blob(git_repository *repo, const git_tree_entry *entry);
 
 static char *get_utf8(struct membuffer *b)

core/parse-xml.c

@@ -1088,7 +1088,7 @@ static int uddf_dive_match(struct dive *dive, const char *name, char *buf, struc
  * We don't do exponentials etc, if somebody does
  * GPS locations in that format, they are insane.
  */
-static degrees_t parse_degrees(char *buf, char **end)
+static degrees_t parse_degrees(const char *buf, const char **end)
 {
 	int sign = 1, decimals = 6, value = 0;
 	degrees_t ret;
@@ -1133,7 +1133,7 @@ static degrees_t parse_degrees(char *buf, char **end)
 
 static void gps_lat(char *buffer, struct dive *dive, struct parser_state *state)
 {
-	char *end;
+	const char *end;
 	location_t location = { };
 	struct dive_site *ds = get_dive_site_for_dive(dive);
 
@@ -1149,7 +1149,7 @@ static void gps_lat(char *buffer, struct dive *dive, struct parser_state *state)
 
 static void gps_long(char *buffer, struct dive *dive, struct parser_state *state)
 {
-	char *end;
+	const char *end;
 	location_t location = { };
 	struct dive_site *ds = get_dive_site_for_dive(dive);
 
@@ -1164,9 +1164,9 @@ static void gps_long(char *buffer, struct dive *dive, struct parser_state *state
 }
 
 /* We allow either spaces or a comma between the decimal degrees */
-void parse_location(char *buffer, location_t *loc)
+void parse_location(const char *buffer, location_t *loc)
 {
-	char *end;
+	const char *end;
 	loc->lat = parse_degrees(buffer, &end);
 	if (*end == ',') end++;
 	loc->lon = parse_degrees(end, &end);

core/units.h

@@ -137,6 +137,8 @@ typedef struct pos {
 	degrees_t lat, lon;
 } location_t;
 
+extern void parse_location(const char *, location_t *);
+
 static inline bool has_location(const location_t *loc)
 {
 	return loc->lat.udeg || loc->lon.udeg;