Added static and const keywords in bunches of places

This helps in self-documenting the interfaces, keeping the
global namespace clean, and providing optimization hints
to the compiler.

correlate.c

@@ -36,20 +36,21 @@
 #include "unixtime.h"
 
 /* Internal functions used to make it work. */
-void Round(struct GPSPoint* First, struct GPSPoint* Result,
-		struct CorrelateOptions* Options, time_t PhotoTime);
-void Interpolate(struct GPSPoint* First, struct GPSPoint* Result,
-		struct CorrelateOptions* Options, time_t PhotoTime);
+static void Round(const struct GPSPoint* First, struct GPSPoint* Result,
+		  time_t PhotoTime);
+static void Interpolate(const struct GPSPoint* First, struct GPSPoint* Result,
+			time_t PhotoTime);
 
 /* This function returns a GPSPoint with the point selected for the
  * file. This allows us to do funky stuff like not actually write
  * the files - ie, just correlate and keep into memory... */
 
-struct GPSPoint* CorrelatePhoto(char* Filename,
+struct GPSPoint* CorrelatePhoto(const char* Filename,
 		struct CorrelateOptions* Options)
 {
 	/* Read out the timestamp from the EXIF data. */
-	char* TimeTemp; int IncludesGPS = 0;
+	char* TimeTemp;
+	int IncludesGPS = 0;
 	TimeTemp = ReadExifDate(Filename, &IncludesGPS);
 	if (!TimeTemp)
 	{
@@ -144,7 +145,7 @@ struct GPSPoint* CorrelatePhoto(char* Filename,
 	/* Time to run through the list, and see if our PhotoTime
 	 * is in between two points. Alternately, it might be
 	 * exactly on a point... even better... */
-	struct GPSPoint* Search;
+	const struct GPSPoint* Search;
 	struct GPSPoint* Actual = malloc(sizeof(struct GPSPoint));
 
 	Options->Result = CORR_NOMATCH; /* For convenience later */
@@ -232,14 +233,12 @@ struct GPSPoint* CorrelatePhoto(char* Filename,
 			if (Options->NoInterpolate)
 			{
 				/* No interpolation. Round. */
-				Round(Search, Actual,
-						Options, PhotoTime);
+				Round(Search, Actual, PhotoTime);
 				Options->Result = CORR_ROUND;
 				break;
 			} else {
 				/* Interpolate away! */
-				Interpolate(Search, Actual,
-						Options, PhotoTime);
+				Interpolate(Search, Actual, PhotoTime);
 				Options->Result = CORR_INTERPOLATED;
 				break;
 			}
@@ -279,12 +278,12 @@ struct GPSPoint* CorrelatePhoto(char* Filename,
 	return NULL;
 };
 
-void Round(struct GPSPoint* First, struct GPSPoint* Result,
-		struct CorrelateOptions* Options, time_t PhotoTime)
+void Round(const struct GPSPoint* First, struct GPSPoint* Result,
+	   time_t PhotoTime)
 {
 	/* Round the point between the two points - ie, it will end
 	 * up being one or the other point. */
-	struct GPSPoint* CopyFrom = NULL;
+	const struct GPSPoint* CopyFrom = NULL;
 
 	/* Determine the difference between the two points. 
 	 * We're using the scale function used by interpolate.
@@ -312,8 +311,8 @@ void Round(struct GPSPoint* First, struct GPSPoint* Result,
 
 }
 
-void Interpolate(struct GPSPoint* First, struct GPSPoint* Result,
-		struct CorrelateOptions* Options, time_t PhotoTime)
+void Interpolate(const struct GPSPoint* First, struct GPSPoint* Result,
+		 time_t PhotoTime)
 {
 	/* Interpolate between the two points. The first point
 	 * is First, the other First->Next. Results into Result. */

correlate.h

@@ -77,6 +77,6 @@ struct CorrelateOptions {
 #define CORR_GPSDATAEXISTS  8
 
 
-struct GPSPoint* CorrelatePhoto(char* Filename, 
+struct GPSPoint* CorrelatePhoto(const char* Filename, 
 		struct CorrelateOptions* Options);
 

exif-gps.cpp

@@ -83,7 +83,7 @@ int main(int argc, char* argv[])
 };
 */
 
-char* ReadExifDate(char* File, int* IncludesGPS)
+char* ReadExifDate(const char* File, int* IncludesGPS)
 {
 	// Open and read the file.
 	Exiv2::ExifData ExifRead;
@@ -143,7 +143,7 @@ char* ReadExifDate(char* File, int* IncludesGPS)
 	return Copy; // Its up to the caller to free this.
 };
 
-char* ReadExifData(char* File, double* Lat, double* Long, double* Elev, int* IncludesGPS)
+char* ReadExifData(const char* File, double* Lat, double* Long, double* Elev, int* IncludesGPS)
 {
 	// This function varies in that it reads
 	// much more data than the last, specifically
@@ -282,7 +282,7 @@ char* ReadExifData(char* File, double* Lat, double* Long, double* Elev, int* Inc
 
 // This function is for the --fix-datestamp option.
 // DateStamp and TimeStamp should be 12-char strings.
-char* ReadGPSTimestamp(char* File, char* DateStamp, char* TimeStamp, int* IncludesGPS)
+char* ReadGPSTimestamp(const char* File, char* DateStamp, char* TimeStamp, int* IncludesGPS)
 {
 	// This function varies in that it reads
 	// much more data than the last, specifically
@@ -436,7 +436,8 @@ void ConvertToRational(double Number,
 
 }
 
-int WriteGPSData(char* File, struct GPSPoint* Point, char* Datum, int NoChangeMtime, int DegMinSecs)
+int WriteGPSData(const char* File, const struct GPSPoint* Point,
+		 const char* Datum, int NoChangeMtime, int DegMinSecs)
 {
 	// Write the GPS data to the file...
 
@@ -651,7 +652,7 @@ int WriteGPSData(char* File, struct GPSPoint* Point, char* Datum, int NoChangeMt
 
 };
 
-int WriteFixedDatestamp(char* File, time_t Time)
+int WriteFixedDatestamp(const char* File, time_t Time)
 {
 	// Write the GPS data to the file...
 
@@ -728,7 +729,7 @@ int WriteFixedDatestamp(char* File, time_t Time)
 	return 1;
 }
 
-int RemoveGPSExif(char* File, int NoChangeMtime)
+int RemoveGPSExif(const char* File, int NoChangeMtime)
 {
 	struct stat statbuf;
 	struct stat statbuf2;

exif-gps.h

@@ -31,12 +31,13 @@
 extern "C" {
 #endif
 
-char* ReadExifDate(char* File, int* IncludesGPS);
-char* ReadExifData(char* File, double* Lat, double* Long, double* Elevation, int* IncludesGPS);
-char* ReadGPSTimestamp(char* File, char* DateStamp, char* TimeStamp, int* IncludesGPS);
-int WriteGPSData(char* File, struct GPSPoint* Point, char* Datum, int NoChangeMtime, int DegMinSecs);
-int WriteFixedDatestamp(char* File, time_t TimeStamp);
-int RemoveGPSExif(char* File, int NoChangeMtime);
+char* ReadExifDate(const char* File, int* IncludesGPS);
+char* ReadExifData(const char* File, double* Lat, double* Long, double* Elevation, int* IncludesGPS);
+char* ReadGPSTimestamp(const char* File, char* DateStamp, char* TimeStamp, int* IncludesGPS);
+int WriteGPSData(const char* File, const struct GPSPoint* Point,
+		 const char* Datum, int NoChangeMtime, int DegMinSecs);
+int WriteFixedDatestamp(const char* File, time_t TimeStamp);
+int RemoveGPSExif(const char* File, int NoChangeMtime);
 
 #ifdef __cplusplus
 }

gpx-read.c

@@ -35,26 +35,26 @@
 #include "unixtime.h"
 #include "gpsstructure.h"
 
-struct GPSPoint* FirstPoint;
-struct GPSPoint* LastPoint;
+static struct GPSPoint* FirstPoint;
+static struct GPSPoint* LastPoint;
 
-void ExtractTrackPoints(xmlNodePtr Start)
+static void ExtractTrackPoints(xmlNodePtr Start)
 {
 	/* The pointer passed to us should be the start
 	 * of a heap of trkpt's. So walk though them,
 	 * extracting what we need. */
 	xmlNodePtr Current = NULL;
 	xmlNodePtr CCurrent = NULL;
 	xmlAttrPtr Properties = NULL;
-	char* Lat;
-	char* Long;
-	char* Elev;
-	char* Time;
+	const char* Lat;
+	const char* Long;
+	const char* Elev;
+	const char* Time;
 
 	for (Current = Start; Current; Current = Current->next)
 	{
 		if ((Current->type == XML_ELEMENT_NODE) &&
-			(strcmp((char *)Current->name, "trkpt") == 0))
+			(strcmp((const char *)Current->name, "trkpt") == 0))
 		{
 			/* This is indeed a trackpoint. Extract! */
 
@@ -72,13 +72,13 @@ void ExtractTrackPoints(xmlNodePtr Start)
 					Properties;
 					Properties = Properties->next)
 			{
-				if (strcmp((char *)Properties->name, "lat") == 0)
+				if (strcmp((const char *)Properties->name, "lat") == 0)
 				{
-					Lat = (char *)Properties->children->content;
+					Lat = (const char *)Properties->children->content;
 				}
-				if (strcmp((char *)Properties->name, "lon") == 0)
+				if (strcmp((const char *)Properties->name, "lon") == 0)
 				{
-					Long = (char *)Properties->children->content;
+					Long = (const char *)Properties->children->content;
 				}
 			}
 
@@ -90,15 +90,15 @@ void ExtractTrackPoints(xmlNodePtr Start)
 					CCurrent;
 					CCurrent = CCurrent->next)
 			{
-				if (strcmp((char *)CCurrent->name, "ele") == 0)
+				if (strcmp((const char *)CCurrent->name, "ele") == 0)
 				{
 					if (CCurrent->children)
-						Elev = (char *)CCurrent->children->content;
+						Elev = (const char *)CCurrent->children->content;
 				}
-				if (strcmp((char *)CCurrent->name, "time") == 0)
+				if (strcmp((const char *)CCurrent->name, "time") == 0)
 				{
 					if (CCurrent->children)
-						Time = (char *)CCurrent->children->content;
+						Time = (const char *)CCurrent->children->content;
 				}
 			}
 
@@ -153,15 +153,15 @@ void ExtractTrackPoints(xmlNodePtr Start)
 	/* Return control to the recursive function... */
 }
 
-void FindTrackSeg(xmlNodePtr Start)
+static void FindTrackSeg(xmlNodePtr Start)
 {
 	/* Go recursive till we find a <trgseg> tag. */
 	xmlNodePtr Current = NULL;
 
 	for (Current = Start; Current; Current = Current->next)
 	{
 		if ((Current->type == XML_ELEMENT_NODE) &&
-			(strcmp((char *)Current->name, "trkseg") == 0))
+			(strcmp((const char *)Current->name, "trkseg") == 0))
 		{
 			/* Found it... the children should
 			 * all be trkpt's. */
@@ -181,7 +181,7 @@ void FindTrackSeg(xmlNodePtr Start)
 }
 
 
-struct GPSPoint* ReadGPX(char* File)
+struct GPSPoint* ReadGPX(const char* File)
 {
 	/* Init the libxml library. Also checks version. */
 	LIBXML_TEST_VERSION
@@ -209,7 +209,7 @@ struct GPSPoint* ReadGPX(char* File)
 
 	/* Check that this is indeed a GPX - the root node
 	 * should be "gpx". */
-	if (strcmp((char *)GPXRoot->name, "gpx") == 0)
+	if (strcmp((const char *)GPXRoot->name, "gpx") == 0)
 	{
 		/* Ok, it is a GPX file. */
 	} else {
@@ -246,7 +246,7 @@ struct GPSPoint* ReadGPX(char* File)
 	FirstPoint = NULL;
 	LastPoint = NULL;
 
-	char* OldLocale = setlocale(LC_NUMERIC, NULL);
+	const char* OldLocale = setlocale(LC_NUMERIC, NULL);
 	setlocale(LC_NUMERIC, "C");
 
 	FindTrackSeg(GPXRoot);
@@ -275,4 +275,3 @@ void FreePointList(struct GPSPoint* List)
 		CurrentFree = NextFree;
 	}
 };
-

gpx-read.h

@@ -25,5 +25,5 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-struct GPSPoint* ReadGPX(char* File);
+struct GPSPoint* ReadGPX(const char* File);
 void FreePointList(struct GPSPoint* List);