Add uint64 formatting helper

src/signOpCert.c

@@ -134,7 +134,7 @@ static void signOpCert_ui_runStep()
 	}
 	UI_STEP(UI_STEP_DISPLAY_KES_PERIOD) {
 		char kesPeriodString[50];
-		snprintf(kesPeriodString, SIZEOF(kesPeriodString), "%llu", ctx->kesPeriod);
+		str_formatUint64(ctx->kesPeriod, kesPeriodString, SIZEOF(kesPeriodString));
 		ui_displayPaginatedText(
 		        "KES period",
 		        kesPeriodString,
@@ -143,7 +143,7 @@ static void signOpCert_ui_runStep()
 	}
 	UI_STEP(UI_STEP_DISPLAY_ISSUE_COUNTER) {
 		char issueCounterString[50];
-		snprintf(issueCounterString, SIZEOF(issueCounterString), "%llu", ctx->issueCounter);
+		str_formatUint64(ctx->issueCounter, issueCounterString, SIZEOF(issueCounterString));
 		ui_displayPaginatedText(
 		        "Issue counter",
 		        issueCounterString,

src/textUtils.c

@@ -59,6 +59,41 @@ size_t str_formatAdaAmount(uint64_t amount, char* out, size_t outSize)
 	return rawSize + suffixLength;
 }
 
+size_t str_formatUint64(uint64_t number, char* out, size_t outSize) {
+	ASSERT(outSize < BUFFER_SIZE_PARANOIA);
+
+	char scratchBuffer[30];
+	char* ptr = BEGIN(scratchBuffer);
+	char* end = END(scratchBuffer);
+
+	// We print in reverse
+	// We want at least one iteration
+	int place = 0;
+	do {
+		WRITE_CHAR(ptr, end, '0' + (number % 10));
+		number /= 10;
+		place++;
+	} while (number > 0);
+
+	// Size without terminating character
+	STATIC_ASSERT(sizeof(ptr - scratchBuffer) == sizeof(size_t), "bad size_t size");
+	size_t rawSize = (size_t) (ptr - scratchBuffer);
+
+	if (rawSize + 1 > outSize) {
+		THROW(ERR_DATA_TOO_LARGE);
+	}
+
+	// Copy reversed & append terminator
+	for (size_t i = 0; i < rawSize; i++) {
+		out[i] = scratchBuffer[rawSize - 1 - i];
+	}
+	out[rawSize] = 0;
+
+	ASSERT(strlen(out) == rawSize);
+
+	return rawSize;
+}
+
 #ifdef DEVEL
 void str_traceAdaAmount(const char* prefix, uint64_t amount)
 {

src/textUtils.h

@@ -5,6 +5,8 @@
 
 size_t str_formatAdaAmount(uint64_t amount, char* out, size_t outSize);
 
+size_t str_formatUint64(uint64_t number, char* out, size_t outSize);
+
 #ifdef DEVEL
 void str_traceAdaAmount(const char *prefix, uint64_t amount);
 #define TRACE_ADA_AMOUNT(PREFIX, AMOUNT) \

src/textUtils_test.c

@@ -78,10 +78,41 @@ void test_formatTtl()
 
 }
 
+void testcase_formatUint64(
+        uint64_t number,
+        const char* expected
+)
+{
+	PRINTF("testcase_formatUint64 %s\n", expected);
+
+	{
+		char tmp[30];
+		size_t len = str_formatUint64(number, tmp, SIZEOF(tmp));
+		EXPECT_EQ(len, strlen(expected));
+		EXPECT_EQ(strcmp(tmp, expected), 0);
+	}
+
+	{
+		// check for buffer overflows
+		char tmp[30];
+		EXPECT_THROWS(str_formatUint64(number, tmp, strlen(expected)), ERR_DATA_TOO_LARGE);
+	}
+}
+
+void test_formatUint64()
+{
+	testcase_formatUint64( 0, "0");
+	testcase_formatUint64( 1, "1");
+	testcase_formatUint64( 4924800, "4924800");
+	testcase_formatUint64( 4924799, "4924799");
+	testcase_formatUint64( -1ll, "18446744073709551615");
+}
+
 void run_textUtils_test()
 {
 	test_formatAda();
 	test_formatTtl();
+	test_formatUint64();
 }
 
 #endif