diff options
-rw-r--r-- | printf.c | 19 | ||||
-rw-r--r-- | test/test_suite.cpp | 53 |
2 files changed, 66 insertions, 6 deletions
@@ -355,13 +355,13 @@ static size_t _vsnprintf(char* buffer, size_t buffer_len, const char* format, va unsigned int flags, width, precision, n;
size_t idx = 0U;
- while (idx < buffer_len) {
- // end reached?
- if (*format == (char)0) {
- buffer[idx] = (char)0;
- break;
- }
+ // check if buffer is valid
+ if (!buffer) {
+ return 0U;
+ }
+ while ((idx < buffer_len) && *format)
+ {
// format specifier? %[flags][width][.precision][length]
if (*format != '%') {
// no
@@ -582,9 +582,16 @@ static size_t _vsnprintf(char* buffer, size_t buffer_len, const char* format, va }
}
+ // termination
+ if (buffer_len > 0U) {
+ buffer[idx == buffer_len ? buffer_len - 1U : idx] = (char)0;
+ }
+
+ // return written chars without terminating \0
return idx;
}
+
///////////////////////////////////////////////////////////////////////////////
int printf(const char* format, ...)
diff --git a/test/test_suite.cpp b/test/test_suite.cpp index a8de789..e152ac7 100644 --- a/test/test_suite.cpp +++ b/test/test_suite.cpp @@ -1017,6 +1017,59 @@ TEST_CASE("unknown flag", "[]" ) { }
+TEST_CASE("buffer length", "[]" ) {
+ char buffer[100];
+ int ret;
+
+ // formatted length, this should return '4',
+ // but this feature is not implemented, returning 0
+ ret = test::snprintf(nullptr, 10, "%s", "Test");
+ REQUIRE(ret == 0);
+ ret = test::snprintf(nullptr, 0, "%s", "Test");
+ REQUIRE(ret == 0);
+
+ buffer[0] = (char)0xA5;
+ ret = test::snprintf(buffer, 0, "%s", "Test");
+ REQUIRE(buffer[0] == (char)0xA5);
+ REQUIRE(ret == 0);
+
+ buffer[0] = 0xCC;
+ test::snprintf(buffer, 1, "%s", "Test");
+ REQUIRE(buffer[0] == '\0');
+
+ test::snprintf(buffer, 2, "%s", "Hello");
+ REQUIRE(!strcmp(buffer, "H"));
+}
+
+
+TEST_CASE("ret value", "[]" ) {
+ char buffer[100] ;
+ int ret;
+
+ ret = test::snprintf(buffer, 6, "0%s", "1234");
+ REQUIRE(!strcmp(buffer, "01234"));
+ REQUIRE(ret == 5);
+
+ ret = test::snprintf(buffer, 6, "0%s", "12345");
+ REQUIRE(!strcmp(buffer, "01234"));
+ REQUIRE(ret == 6); // '5' is truncated
+
+ ret = test::snprintf(buffer, 6, "0%s", "1234567");
+ REQUIRE(!strcmp(buffer, "01234"));
+ REQUIRE(ret == 6); // '567' are truncated
+
+ ret = test::snprintf(buffer, 10, "hello, world");
+ REQUIRE(ret == 10);
+
+ ret = test::snprintf(buffer, 3, "%d", 10000);
+ REQUIRE(ret == 3); // '000' are truncated
+ REQUIRE(strlen(buffer) == 2U);
+ REQUIRE(buffer[0] == '1');
+ REQUIRE(buffer[1] == '0');
+ REQUIRE(buffer[2] == '\0');
+}
+
+
TEST_CASE("misc", "[]" ) {
char buffer[100];
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