Cleanup: fix "unsave" snprintf()s in plannernotes.c

The planner notes were constructed using a sequence of
  len += snprintf(buf, buflen - len, ...);
calls. This will fail once len > buflen, because the second parameter
of snprintf is unsigned. Note that snprintf returns the number of
bytes that would have been written if it weren't truncated.

Fix this by using membuffer with put_format()/put_string() and
asprintf_loc().

Fixes #1155.

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

1 files changed, 107 insertions, 134 deletions

diff --git a/core/plannernotes.c b/core/plannernotes.c
index e05f27738..eb6dc018f 100644
--- a/core/plannernotes.c
+++ b/core/plannernotes.c
@@ -18,6 +18,7 @@
 #include "qthelper.h"
 #include "format.h"
 #include "version.h"
+#include "membuffer.h"
 
 static int diveplan_duration(struct diveplan *diveplan)
 {
@@ -41,28 +42,21 @@ static int diveplan_duration(struct diveplan *diveplan)
  *             5) Pointers to gas mixes in the gas change: gas-from and gas-to.
  * Returns:    The size of the output buffer that has been used after the new results have been added.
  */
-static int add_icd_entry(char *icdbuffer, unsigned int maxsize, struct icd_data *icdvalues, bool printheader, int time_seconds, int ambientpressure_mbar, struct gasmix *gas_from, struct gasmix *gas_to)
+static void add_icd_entry(struct membuffer *b, struct icd_data *icdvalues, bool printheader, int time_seconds, int ambientpressure_mbar, struct gasmix *gas_from, struct gasmix *gas_to)
 {
-	int len = 0;
 	if (printheader) { // Create a table description and a table header if no icd data have been written yet.
-		len = snprintf(icdbuffer + len, maxsize - len, "<div>%s:",
-			translate("gettextFromC","Isobaric counterdiffusion information"));
-		len += snprintf(icdbuffer + len, maxsize - len, "<table><tr><td align='left'><b>%s</b></td>",
-			translate("gettextFromC", "runtime"));
-		len += snprintf(icdbuffer + len, maxsize - len, "<td align='center'><b>%s</b></td>",
-			translate("gettextFromC", "gaschange"));
-		len += snprintf(icdbuffer + len, maxsize - len, "<td style='padding-left: 15px;'><b>%s</b></td>",
-			translate("gettextFromC", "&#916;He"));
-		len += snprintf(icdbuffer + len, maxsize - len, "<td style='padding-left: 20px;'><b>%s</b></td>",
-			translate("gettextFromC", "&#916;N&#8322;"));
-		len += snprintf(icdbuffer + len, maxsize - len, "<td style='padding-left: 10px;'><b>%s</b></td></tr>",
-			translate("gettextFromC", "max &#916;N&#8322;"));
+		put_format(b, "<div>%s:", translate("gettextFromC","Isobaric counterdiffusion information"));
+		put_format(b, "<table><tr><td align='left'><b>%s</b></td>", translate("gettextFromC", "runtime"));
+		put_format(b, "<td align='center'><b>%s</b></td>", translate("gettextFromC", "gaschange"));
+		put_format(b, "<td style='padding-left: 15px;'><b>%s</b></td>", translate("gettextFromC", "&#916;He"));
+		put_format(b, "<td style='padding-left: 20px;'><b>%s</b></td>", translate("gettextFromC", "&#916;N&#8322;"));
+		put_format(b, "<td style='padding-left: 10px;'><b>%s</b></td></tr>", translate("gettextFromC", "max &#916;N&#8322;"));
 	}		// Add one entry to the icd table:
-	len += snprintf_loc(icdbuffer + len, maxsize - len,
+	put_format_loc(b,
 		"<tr><td rowspan='2' style= 'vertical-align:top;'>%3d%s</td>"
 		"<td rowspan=2 style= 'vertical-align:top;'>%s&#10137;",
 		(time_seconds + 30) / 60, translate("gettextFromC", "min"), gasname(gas_from));
-	len += snprintf_loc(icdbuffer + len, maxsize - len,
+	put_format_loc(b,
 		"%s</td><td style='padding-left: 10px;'>%+5.1f%%</td>"
 		"<td style= 'padding-left: 15px; color:%s;'>%+5.1f%%</td>"
 		"<td style='padding-left: 15px;'>%+5.1f%%</td></tr>"
@@ -74,21 +68,14 @@ static int add_icd_entry(char *icdbuffer, unsigned int maxsize, struct icd_data
 		ambientpressure_mbar * icdvalues->dHe / 1e6f, translate("gettextFromC", "bar"), ((5 * icdvalues->dN2) > -icdvalues->dHe) ? "red" : "#383838",
 		ambientpressure_mbar * icdvalues->dN2 / 1e6f, translate("gettextFromC", "bar"),
 		ambientpressure_mbar * -icdvalues->dHe / 5e6f, translate("gettextFromC", "bar"));
-	return len;
 }
 
 void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_disclaimer, int error)
 {
-	const unsigned int sz_buffer = 2000000;
-	const unsigned int sz_temp = 100000;
-	const unsigned int sz_icdbuf = 10000;
-	char *buffer = (char *)malloc(sz_buffer);
-	char *temp = (char *)malloc(sz_temp);
-	char *icdbuffer = (char *)malloc(sz_icdbuf);
+	struct membuffer buf = { 0 };
+	struct membuffer icdbuf = { 0 };
 	const char *deco, *segmentsymbol;
-	static char buf[1000];
-	int len, lastdepth = 0, lasttime = 0, lastsetpoint = -1, newdepth = 0, lastprintdepth = 0, lastprintsetpoint = -1;
-	int icdlen = 0;
+	int lastdepth = 0, lasttime = 0, lastsetpoint = -1, newdepth = 0, lastprintdepth = 0, lastprintsetpoint = -1;
 	struct gasmix lastprintgasmix = {{ -1 }, { -1 }};
 	struct divedatapoint *dp = diveplan->dp;
 	bool plan_verbatim = prefs.verbatim_plan;
@@ -102,6 +89,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 	struct divedatapoint *nextdp = NULL;
 	struct divedatapoint *lastbottomdp = NULL;
 	struct icd_data icdvalues;
+	char *temp;
 
 	if (decoMode() == VPMB) {
 		deco = translate("gettextFromC", "VPM-B");
@@ -109,36 +97,34 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		deco = translate("gettextFromC", "BUHLMANN");
 	}
 
-	snprintf(buf, sizeof(buf), translate("gettextFromC", "DISCLAIMER / WARNING: THIS IS A NEW IMPLEMENTATION OF THE %s "
-		"ALGORITHM AND A DIVE PLANNER IMPLEMENTATION BASED ON THAT WHICH HAS "
-		"RECEIVED ONLY A LIMITED AMOUNT OF TESTING. WE STRONGLY RECOMMEND NOT TO "
-		"PLAN DIVES SIMPLY BASED ON THE RESULTS GIVEN HERE."), deco);
-	disclaimer = buf;
-
 	if (!dp)
-		goto finished;
+		return;
 
 	if (error) {
-		snprintf(temp, sz_temp, "%s",
-			translate("gettextFromC", "Decompression calculation aborted due to excessive time"));
-		snprintf(buffer, sz_buffer, "<span style='color: red;'>%s </span> %s<br>",
-			translate("gettextFromC", "Warning:"), temp);
-		dive->notes = strdup(buffer);
+		put_format(&buf, "<span style='color: red;'>%s </span> %s<br>",
+				translate("gettextFromC", "Warning:"),
+				translate("gettextFromC", "Decompression calculation aborted due to excessive time"));
 		goto finished;
 	}
 
-	len = show_disclaimer ? snprintf(buffer, sz_buffer, "<div><b>%s</b><br></div>", disclaimer) : 0;
+	if (show_disclaimer) {
+		put_string(&buf, "<div><b>");
+		put_format(&buf, translate("gettextFromC", "DISCLAIMER / WARNING: THIS IS A NEW IMPLEMENTATION OF THE %s "
+			"ALGORITHM AND A DIVE PLANNER IMPLEMENTATION BASED ON THAT WHICH HAS "
+			"RECEIVED ONLY A LIMITED AMOUNT OF TESTING. WE STRONGLY RECOMMEND NOT TO "
+			"PLAN DIVES SIMPLY BASED ON THE RESULTS GIVEN HERE."), deco);
+		put_string(&buf, "</b><br></div>");
+	}
 
 	if (diveplan->surface_interval < 0) {
-		len += snprintf(buffer + len, sz_buffer - len, "<div><b>%s (%s) %s<br>",
+		put_format(&buf, "<div><b>%s (%s) %s<br>",
 			translate("gettextFromC", "Subsurface"),
 			subsurface_canonical_version(),
 			translate("gettextFromC", "dive plan</b> (overlapping dives detected)"));
-		dive->notes = strdup(buffer);
 		goto finished;
 	} else if (diveplan->surface_interval >= 48 * 60 *60) {
 		char *current_date = get_current_date();
-		len += snprintf(buffer + len, sz_buffer - len, "<div><b>%s (%s) %s %s</b><br>",
+		put_format(&buf, "<div><b>%s (%s) %s %s</b><br>",
 			translate("gettextFromC", "Subsurface"),
 			subsurface_canonical_version(),
 			translate("gettextFromC", "dive plan</b> created on"),
@@ -146,7 +132,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		free(current_date);
 	} else {
 		char *current_date = get_current_date();
-		len += snprintf_loc(buffer + len, sz_buffer - len, "<div><b>%s (%s) %s %d:%02d) %s %s<br>",
+		put_format_loc(&buf, "<div><b>%s (%s) %s %d:%02d) %s %s<br>",
 			translate("gettextFromC", "Subsurface"),
 			subsurface_canonical_version(),
 			translate("gettextFromC", "dive plan</b> (surface interval "),
@@ -157,23 +143,19 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 	}
 
 	if (prefs.display_variations && decoMode() != RECREATIONAL)
-		len += snprintf_loc(buffer + len, sz_buffer - len, translate("gettextFromC", "Runtime: %dmin%s"),
+		put_format_loc(&buf, translate("gettextFromC", "Runtime: %dmin%s"),
 			diveplan_duration(diveplan), "VARIATIONS<br></div>");
 	else
-		len += snprintf_loc(buffer + len, sz_buffer - len, translate("gettextFromC", "Runtime: %dmin<br></div>"),
+		put_format_loc(&buf, translate("gettextFromC", "Runtime: %dmin<br></div>"),
 			diveplan_duration(diveplan));
 
 	if (!plan_verbatim) {
-		len += snprintf(buffer + len, sz_buffer - len, "<table><thead><tr><th></th><th>%s</th>",
-			translate("gettextFromC", "depth"));
+		put_format(&buf, "<table><thead><tr><th></th><th>%s</th>", translate("gettextFromC", "depth"));
 		if (plan_display_duration)
-			len += snprintf(buffer + len, sz_buffer - len, "<th style='padding-left: 10px;'>%s</th>",
-				translate("gettextFromC", "duration"));
+			put_format(&buf, "<th style='padding-left: 10px;'>%s</th>", translate("gettextFromC", "duration"));
 		if (plan_display_runtime)
-			len += snprintf(buffer + len, sz_buffer - len, "<th style='padding-left: 10px;'>%s</th>",
-				translate("gettextFromC", "runtime"));
-		len += snprintf(buffer + len, sz_buffer - len,
-				"<th style='padding-left: 10px; float: left;'>%s</th></tr></thead><tbody style='float: left;'>",
+			put_format(&buf, "<th style='padding-left: 10px;'>%s</th>", translate("gettextFromC", "runtime"));
+		put_format(&buf, "<th style='padding-left: 10px; float: left;'>%s</th></tr></thead><tbody style='float: left;'>",
 				translate("gettextFromC", "gas"));
 	}
 
@@ -211,7 +193,6 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		if (dp->entered && !nextdp->entered)
 			lastbottomdp = dp;
 
-		len = strlen(buffer);
 		if (plan_verbatim) {
 			/* When displaying a verbatim plan, we output a waypoint for every gas change.
 			 * Therefore, we do not need to test for difficult cases that mean we need to
@@ -222,7 +203,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			if (dp->depth.mm != lastprintdepth) {
 				if (plan_display_transitions || dp->entered || !dp->next || (gaschange_after && dp->next && dp->depth.mm != nextdp->depth.mm)) {
 					if (dp->setpoint) {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "%s to %.*f %s in %d:%02d min - runtime %d:%02u on %s (SP = %.1fbar)"),
+						put_format_loc(&buf, translate("gettextFromC", "%s to %.*f %s in %d:%02d min - runtime %d:%02u on %s (SP = %.1fbar)"),
 							     dp->depth.mm < lastprintdepth ? translate("gettextFromC", "Ascend") : translate("gettextFromC", "Descend"),
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
@@ -230,34 +211,35 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 							     gasname(&gasmix),
 							     (double) dp->setpoint / 1000.0);
 					} else {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "%s to %.*f %s in %d:%02d min - runtime %d:%02u on %s"),
+						put_format_loc(&buf, translate("gettextFromC", "%s to %.*f %s in %d:%02d min - runtime %d:%02u on %s"),
 							     dp->depth.mm < lastprintdepth ? translate("gettextFromC", "Ascend") : translate("gettextFromC", "Descend"),
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
 							     gasname(&gasmix));
 					}
-					len += snprintf(buffer + len, sz_buffer - len, "%s<br>", temp);
+
+					put_string(&buf, "<br>");
 				}
 				newdepth = dp->depth.mm;
 				lasttime = dp->time;
 			} else {
 				if ((nextdp && dp->depth.mm != nextdp->depth.mm) || gaschange_after) {
 					if (dp->setpoint) {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s (SP = %.1fbar)"),
+						put_format_loc(&buf, translate("gettextFromC", "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s (SP = %.1fbar)"),
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
 							     gasname(&gasmix),
 							     (double) dp->setpoint / 1000.0);
 					} else {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s"),
+						put_format_loc(&buf, translate("gettextFromC", "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s"),
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
 							     gasname(&gasmix));
 					}
-					len += snprintf(buffer + len, sz_buffer - len, "%s<br>", temp);
+					put_string(&buf, "<br>");
 					newdepth = dp->depth.mm;
 					lasttime = dp->time;
 				}
@@ -295,17 +277,20 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 				else
 					segmentsymbol = "-";        // minus sign (a.k.a. horizontal line) for deco stop
 
-				len += snprintf(buffer + len, sz_buffer - len, "<tr><td style='padding-left: 10px; float: right;'>%s</td>", segmentsymbol);
+				put_format(&buf, "<tr><td style='padding-left: 10px; float: right;'>%s</td>", segmentsymbol);
 
-				snprintf(temp, sz_temp, translate("gettextFromC", "%3.0f%s"), depthvalue, depth_unit);
-				len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+				asprintf_loc(&temp, translate("gettextFromC", "%3.0f%s"), depthvalue, depth_unit);
+				put_format(&buf, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+				free(temp);
 				if (plan_display_duration) {
-					snprintf(temp, sz_temp, translate("gettextFromC", "%3dmin"), (dp->time - lasttime + 30) / 60);
-					len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+					asprintf_loc(&temp, translate("gettextFromC", "%3dmin"), (dp->time - lasttime + 30) / 60);
+					put_format(&buf, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+					free(temp);
 				}
 				if (plan_display_runtime) {
-					snprintf(temp, sz_temp, translate("gettextFromC", "%3dmin"), (dp->time + 30) / 60);
-					len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+					asprintf_loc(&temp, translate("gettextFromC", "%3dmin"), (dp->time + 30) / 60);
+					put_format(&buf, "<td style='padding-left: 10px; float: right;'>%s</td>", temp);
+					free(temp);
 				}
 
 				/* Normally a gas change is displayed on the stopping segment, so only display a gas change at the end of
@@ -313,17 +298,18 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 				 */
 				if ((isascent || dp->entered) && gaschange_after && dp->next && nextdp && (dp->depth.mm != nextdp->depth.mm || nextdp->entered)) {
 					if (dp->setpoint) {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "(SP = %.1fbar)"), (double) nextdp->setpoint / 1000.0);
-						len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>",
+						asprintf_loc(&temp, translate("gettextFromC", "(SP = %.1fbar)"), nextdp->setpoint / 1000.0);
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>",
 							gasname(&newgasmix), temp);
+						free(temp);
 					} else {
-						len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; color: red; float: left;'><b>%s</b></td>",
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s</b></td>",
 							gasname(&newgasmix));
 						if (isascent && (get_he(&lastprintgasmix) > 0)) { // For a trimix gas change on ascent, save ICD info if previous cylinder had helium
 							if (isobaric_counterdiffusion(&lastprintgasmix, &newgasmix, &icdvalues)) // Do icd calulations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								icdlen += add_icd_entry(icdbuffer+icdlen, sz_icdbuf-icdlen, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // .. then print calculations to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // .. then print calculations to buffer.
 								icdtableheader = false;
 							}
 						}
@@ -334,17 +320,16 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 				} else if (gaschange_before) {
 					// If a new gas has been used for this segment, now is the time to show it
 					if (dp->setpoint) {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "(SP = %.1fbar)"), (double) dp->setpoint / 1000.0);
-						len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>",
-							gasname(&gasmix), temp);
+						asprintf_loc(&temp, translate("gettextFromC", "(SP = %.1fbar)"), (double) dp->setpoint / 1000.0);
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>", gasname(&gasmix), temp);
+						free(temp);
 					} else {
-						len += snprintf(buffer + len, sz_buffer - len, "<td style='padding-left: 10px; color: red; float: left;'><b>%s</b></td>",
-							gasname(&gasmix));
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s</b></td>", gasname(&gasmix));
 						if (get_he(&lastprintgasmix) > 0) {  // For a trimix gas change, save ICD info if previous cylinder had helium
 							if (isobaric_counterdiffusion(&lastprintgasmix, &gasmix, &icdvalues))  // Do icd calculations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								icdlen += add_icd_entry(icdbuffer+icdlen, sz_icdbuf-icdlen, &icdvalues, icdtableheader, lasttime, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &gasmix); // .. then print data to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, lasttime, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &gasmix); // .. then print data to buffer.
 								icdtableheader = false;
 							}
 						}
@@ -354,9 +339,9 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 					lastprintgasmix = gasmix;
 					gaschange_after = false;
 				} else {
-					len += snprintf(buffer + len, sz_buffer - len, "<td>&nbsp;</td>");
+					put_string(&buf, "<td>&nbsp;</td>");
 				}
-				len += snprintf(buffer + len, sz_buffer - len, "</tr>");
+				put_string(&buf, "</tr>");
 				newdepth = dp->depth.mm;
 				lasttime = dp->time;
 			}
@@ -366,19 +351,19 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			if (plan_verbatim) {
 				if (lastsetpoint >= 0) {
 					if (nextdp && nextdp->setpoint) {
-						snprintf_loc(temp, sz_temp, translate("gettextFromC", "Switch gas to %s (SP = %.1fbar)"), gasname(&newgasmix), (double) nextdp->setpoint / 1000.0);
+						put_format_loc(&buf, translate("gettextFromC", "Switch gas to %s (SP = %.1fbar)"), gasname(&newgasmix), (double) nextdp->setpoint / 1000.0);
 					} else {
-						snprintf(temp, sz_temp, translate("gettextFromC", "Switch gas to %s"), gasname(&newgasmix));
+						put_format(&buf, translate("gettextFromC", "Switch gas to %s"), gasname(&newgasmix));
 						if ((isascent) && (get_he(&lastprintgasmix) > 0)) {          // For a trimix gas change on ascent:
 							if (isobaric_counterdiffusion(&lastprintgasmix, &newgasmix, &icdvalues)) // Do icd calculations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								icdlen += add_icd_entry(icdbuffer+icdlen, sz_icdbuf-icdlen, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // ... then print data to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // ... then print data to buffer.
 								icdtableheader = false;
 							}
 						}
 					}
-					len += snprintf(buffer + len, sz_buffer - len, "%s<br>", temp);
+					put_string(&buf, "<br>");
 				}
 				lastprintgasmix = newgasmix;
 				gaschange_after = false;
@@ -391,42 +376,36 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		lastentered = dp->entered;
 	} while ((dp = nextdp) != NULL);
 	if (!plan_verbatim)
-		len += snprintf(buffer + len, sz_buffer - len, "</tbody></table><br>");
+		put_string(&buf, "</tbody></table><br>");
 
 	/* Print the CNS and OTU next.*/
 	dive->cns = 0;
 	dive->maxcns = 0;
 	update_cylinder_related_info(dive);
-	snprintf(temp, sz_temp, "%s", translate("gettextFromC", "CNS"));
-	len += snprintf_loc(buffer + len, sz_buffer - len, "<div>%s: %i%%", temp, dive->cns);
-	snprintf(temp, sz_temp, "%s", translate("gettextFromC", "OTU"));
-	len += snprintf_loc(buffer + len, sz_buffer - len, "<br>%s: %i<br></div>", temp, dive->otu);
+	put_format_loc(&buf, "<div>%s: %i%%", translate("gettextFromC", "CNS"), dive->cns);
+	put_format_loc(&buf, "<br>%s: %i<br></div>", translate("gettextFromC", "OTU"), dive->otu);
 
 	/* Print the settings for the diveplan next. */
+	put_string(&buf, "<div>");
 	if (decoMode() == BUEHLMANN) {
-		snprintf_loc(temp, sz_temp, translate("gettextFromC", "Deco model: Bühlmann ZHL-16C with GFLow = %d%% and GFHigh = %d%%"),
-			     diveplan->gflow, diveplan->gfhigh);
+		put_format_loc(&buf, translate("gettextFromC", "Deco model: Bühlmann ZHL-16C with GFLow = %d%% and GFHigh = %d%%"), diveplan->gflow, diveplan->gfhigh);
 	} else if (decoMode() == VPMB){
-		int temp_len;
 		if (diveplan->vpmb_conservatism == 0)
-			temp_len = snprintf(temp, sz_temp, "%s", translate("gettextFromC", "Deco model: VPM-B at nominal conservatism"));
+			put_string(&buf, translate("gettextFromC", "Deco model: VPM-B at nominal conservatism"));
 		else
-			temp_len = snprintf_loc(temp, sz_temp, translate("gettextFromC", "Deco model: VPM-B at +%d conservatism"), diveplan->vpmb_conservatism);
+			put_format_loc(&buf, translate("gettextFromC", "Deco model: VPM-B at +%d conservatism"), diveplan->vpmb_conservatism);
 		if (diveplan->eff_gflow)
-			temp_len += snprintf_loc(temp + temp_len, sz_temp - temp_len,  translate("gettextFromC", ", effective GF=%d/%d"), diveplan->eff_gflow,
-				diveplan->eff_gfhigh);
-
+			put_format_loc(&buf,  translate("gettextFromC", ", effective GF=%d/%d"), diveplan->eff_gflow, diveplan->eff_gfhigh);
 	} else if (decoMode() == RECREATIONAL){
-		snprintf_loc(temp, sz_temp, translate("gettextFromC", "Deco model: Recreational mode based on Bühlmann ZHL-16B with GFLow = %d%% and GFHigh = %d%%"),
+		put_format_loc(&buf, translate("gettextFromC", "Deco model: Recreational mode based on Bühlmann ZHL-16B with GFLow = %d%% and GFHigh = %d%%"),
 			     diveplan->gflow, diveplan->gfhigh);
 	}
-	len += snprintf(buffer + len, sz_buffer - len, "<div>%s<br>",temp);
+	put_string(&buf, "<br>");
 
 	const char *depth_unit;
 	int altitude = (int) get_depth_units((int) (log(1013.0 / diveplan->surface_pressure) * 7800000), NULL, &depth_unit);
 
-	len += snprintf_loc(buffer + len, sz_buffer - len, translate("gettextFromC", "ATM pressure: %dmbar (%d%s)<br></div>"),
-			    diveplan->surface_pressure, altitude, depth_unit);
+	put_format_loc(&buf, translate("gettextFromC", "ATM pressure: %dmbar (%d%s)<br></div>"), diveplan->surface_pressure, altitude, depth_unit);
 
 	/* Get SAC values and units for printing it in gas consumption */
 	double bottomsacvalue, decosacvalue;
@@ -441,11 +420,12 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 
 	/* Print the gas consumption next.*/
 	if (dive->dc.divemode == CCR)
-		snprintf(temp, sz_temp, "%s", translate("gettextFromC", "Gas consumption (CCR legs excluded):"));
+		temp = strdup(translate("gettextFromC", "Gas consumption (CCR legs excluded):"));
 	else
-		snprintf_loc(temp, sz_temp, "%s %.*f|%.*f%s/min):", translate("gettextFromC", "Gas consumption (based on SAC"),
+		asprintf_loc(&temp, "%s %.*f|%.*f%s/min):", translate("gettextFromC", "Gas consumption (based on SAC"),
 			     sacdecimals, bottomsacvalue, sacdecimals, decosacvalue, sacunit);
-	len += snprintf(buffer + len, sz_buffer - len, "<div>%s<br>", temp);
+	put_format(&buf, "<div>%s<br>", temp);
+	free(temp);
 
 	/* Print gas consumption: This loop covers all cylinders */
 	for (int gasidx = 0; gasidx < MAX_CYLINDERS; gasidx++) {
@@ -521,36 +501,38 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 				}
 			/* Print the gas consumption for every cylinder here to temp buffer. */
 			if (lrint(volume) > 0) {
-				snprintf_loc(temp, sz_temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s/%.0f%s in planned ascent)"),
+				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s/%.0f%s in planned ascent)"),
 					     volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix), deco_volume, unit, deco_pressure, pressure_unit);
 			} else {
-				snprintf_loc(temp, sz_temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span>"),
+				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span>"),
 					     volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix));
 			}
 		} else {
 			if (lrint(volume) > 0) {
-				snprintf_loc(temp, sz_temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s during planned ascent)"),
+				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s during planned ascent)"),
 					     volume, unit, gasname(&cyl->gasmix), deco_volume, unit);
 			} else {
-				snprintf_loc(temp, sz_temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span>"),
+				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span>"),
 					     volume, unit, gasname(&cyl->gasmix));
 			}
 		}
 		/* Gas consumption: Now finally print all strings to output */
-		len += snprintf(buffer + len, sz_buffer - len, "%s%s%s<br></div>", temp, warning, mingas);
+		put_format(&buf, "%s%s%s<br></div>", temp, warning, mingas);
+		free(temp);
 	}
 
 	/* For trimix OC dives, if an icd table header and icd data were printed to buffer, then add the ICD table here */
 	if (!icdtableheader && prefs.show_icd) {
-		icdlen += snprintf(icdbuffer + icdlen, sz_icdbuf - icdlen,"</tbody></table>"); // End the ICD table
-		len += snprintf(buffer + len, sz_buffer - len, "%s", icdbuffer); // ..and add it to the html buffer
+		put_string(&icdbuf, "</tbody></table>"); // End the ICD table
+		put_string(&buf, icdbuf.buffer); // ..and add it to the html buffer
 		if (icdwarning) { // If necessary, add warning
-			len += snprintf(buffer + len, sz_buffer - len, "<span style='color: red;'>%s</span> %s",
+			put_format(&buf, "<span style='color: red;'>%s</span> %s",
 				translate("gettextFromC", "Warning:"),
 				translate("gettextFromC", "Isobaric counterdiffusion conditions exceeded"));
 		}
-		len += snprintf(buffer + len, sz_buffer - len, "<br></div>");
+		put_string(&buf, "<br></div>");
 	}
+	free_buffer(&icdbuf);
 
 	/* Print warnings for pO2 */
 	dp = diveplan->dp;
@@ -566,40 +548,31 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 					const char *depth_unit;
 					int decimals;
 					double depth_value = get_depth_units(dp->depth.mm, &decimals, &depth_unit);
-					len = strlen(buffer);
 					if (!o2warning_exist)
-						len += snprintf(buffer + len, sz_buffer - len, "<div>");
+						put_string(&buf, "<div>");
 					o2warning_exist = true;
-					snprintf_loc(temp, sz_temp,
-						     translate("gettextFromC", "high pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
-						     pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
-					len += snprintf(buffer + len, sz_buffer - len, "<span style='color: red;'>%s </span> %s<br>",
-							translate("gettextFromC", "Warning:"), temp);
+					asprintf_loc(&temp, translate("gettextFromC", "high pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
+						pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
+					put_format(&buf, "<span style='color: red;'>%s </span> %s<br>", translate("gettextFromC", "Warning:"), temp);
+					free(temp);
 				} else if (pressures.o2 < 0.16) {
 					const char *depth_unit;
 					int decimals;
 					double depth_value = get_depth_units(dp->depth.mm, &decimals, &depth_unit);
-					len = strlen(buffer);
 					if (!o2warning_exist)
-						len += snprintf(buffer + len, sz_buffer - len, "<div>");
+						put_string(&buf, "<div>");
 					o2warning_exist = true;
-					snprintf_loc(temp, sz_temp,
-						     translate("gettextFromC", "low pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
-						     pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
-					len += snprintf(buffer + len, sz_buffer - len, "<span style='color: red;'>%s </span> %s<br>",
-							translate("gettextFromC", "Warning:"), temp);
-
+					asprintf_loc(&temp, translate("gettextFromC", "low pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
+						pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
+					put_format(&buf, "<span style='color: red;'>%s </span> %s<br>", translate("gettextFromC", "Warning:"), temp);
+					free(temp);
 				}
 			}
 			dp = dp->next;
 		}
 	}
-	snprintf(buffer + len, sz_buffer - len, "</div>");
-	dive->notes = strdup(buffer);
-
+	put_string(&buf, "</div>");
 finished:
-	free((void *)buffer);
-	free((void *)temp);
-	free((void *)icdbuffer);
-
+	mb_cstring(&buf);
+	dive->notes = detach_buffer(&buf);
 }