Add ability to 'save' dives

This just generates another xml file.  Don't get me wrong: I still don't
like xml, but this way we can save in the same format we load things
from.  Except the save-format is a *lot* cleaner than the abortion that
is Suunto or libdivecomputer xml.

Don't bother with some crazy xml library crap for saving. Just do it!

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Makefile

@@ -1,7 +1,7 @@
 CC=gcc
 CFLAGS=-Wall -Wno-pointer-sign -g
 
-OBJS=main.o profile.o info.o divelist.o parse-xml.o
+OBJS=main.o profile.o info.o divelist.o parse-xml.o save-xml.o
 
 divelog: $(OBJS)
 	$(CC) $(LDLAGS) -o divelog $(OBJS) \
@@ -11,6 +11,9 @@ divelog: $(OBJS)
 parse-xml.o: parse-xml.c dive.h
 	$(CC) $(CFLAGS) -c `xml2-config --cflags` parse-xml.c
 
+save-xml.o: save-xml.c dive.h
+	$(CC) $(CFLAGS) -c save-xml.c
+
 main.o: main.c dive.h display.h
 	$(CC) $(CFLAGS) `pkg-config --cflags gtk+-2.0` -c main.c
 

dive.h

@@ -133,4 +133,6 @@ static inline struct dive *get_dive(unsigned int nr)
 extern void parse_xml_init(void);
 extern void parse_xml_file(const char *filename);
 
+void save_dives(const char *filename);
+
 #endif /* DIVE_H */

main.c

@@ -96,7 +96,7 @@ static void file_save(GtkWidget *w, gpointer data)
 	if (gtk_dialog_run(GTK_DIALOG(dialog)) == GTK_RESPONSE_ACCEPT) {
 		char *filename;
 		filename = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(dialog));
-		printf("Save: '%s'\n", filename);
+		save_dives(filename);
 		g_free(filename);
 	}
 	gtk_widget_destroy(dialog);

save-xml.c

@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <time.h>
+
+#include "dive.h"
+
+#define FRACTION(n,x) ((unsigned)(n)/(x)),((unsigned)(n)%(x))
+
+static void show_temperature(FILE *f, temperature_t temp, const char *pre, const char *post)
+{
+	if (temp.mkelvin) {
+		int mcelsius = temp.mkelvin - 273150;
+		const char *sign ="";
+		if (mcelsius < 0) {
+			sign = "-";
+			mcelsius = - mcelsius;
+		}
+		fprintf(f, "%s%s%u.%03u%s", pre, sign, FRACTION(mcelsius, 1000), post);
+	}
+}
+
+static void save_overview(FILE *f, struct dive *dive)
+{
+	fprintf(f, "  <maxdepth>%u.%03u m</maxdepth>\n", FRACTION(dive->maxdepth.mm, 1000));
+	show_temperature(f, dive->airtemp, "  <airtemp>", " C</airtemp>\n");
+}
+
+static void save_gasmix(FILE *f, struct dive *dive)
+{
+	int i;
+
+	for (i = 0; i < MAX_MIXES; i++) {
+		gasmix_t *mix = dive->gasmix+i;
+		int o2 = mix->o2.permille, he = mix->he.permille;
+		int n2 = 1000 - o2 - he;
+
+		if (!mix->o2.permille)
+			return;
+		fprintf(f, "  <gasmix o2='%u.%u%%'", FRACTION(o2, 10));
+		if (mix->he.permille)
+			fprintf(f, " he='%u.%u%%'", FRACTION(he, 10));
+		fprintf(f, " n2='%u.%u%%'></gasmix>\n", FRACTION(n2, 10));
+	}
+}
+
+static void save_sample(FILE *f, struct sample *sample)
+{
+	fprintf(f, "  <sample time='%u:%02u' depth='%u.%03u'",
+		FRACTION(sample->time.seconds,60),
+		FRACTION(sample->depth.mm, 1000));
+	show_temperature(f, sample->temperature, " temp='", " C'");
+	if (sample->tankpressure.mbar) {
+		fprintf(f, " tankpressure='%u.%03u bar'",
+			FRACTION(sample->tankpressure.mbar, 1000));
+	}
+	fprintf(f, "></sample>\n");
+}
+
+static void save_dive(FILE *f, struct dive *dive)
+{
+	int i;
+	struct tm *tm = gmtime(&dive->when);
+
+	fprintf(f, "<dive date='%02u.%02u.%u' time='%02u:%02u:%02u'>\n",
+		tm->tm_mday, tm->tm_mon+1, tm->tm_year+1900,
+		tm->tm_hour, tm->tm_min, tm->tm_sec);
+	save_overview(f, dive);
+	save_gasmix(f, dive);
+	for (i = 0; i < dive->samples; i++)
+		save_sample(f, dive->sample+i);
+	fprintf(f, "</dive>\n");
+}
+
+#define VERSION 1
+
+void save_dives(const char *filename)
+{
+	int i;
+	FILE *f = fopen(filename, "w");
+
+	if (!f)
+		return;
+	fprintf(f, "<dives>\n<program name='diveclog' version='%d'></program>\n", VERSION);
+	for (i = 0; i < dive_table.nr; i++)
+		save_dive(f, get_dive(i));
+	fprintf(f, "</dives>\n");
+}