Add an implementation of the BSD function `strtonum` (#2238)

The main difference with the original function is that we allow to
specify the base.
Credit for the original idea and the first implementation to @0xA50C1A1

3 files changed, 62 insertions, 0 deletions

diff --git a/example/ndpiReader.c b/example/ndpiReader.c
index ce697026d..3fba97bbf 100644
--- a/example/ndpiReader.c
+++ b/example/ndpiReader.c
@@ -5377,6 +5377,29 @@ void compressedBitmapUnitTest() {
 
 /* *********************************************** */
 
+void strtonumUnitTest() {
+  const char *errstrp;
+
+  assert(ndpi_strtonum("0", -10, +10, &errstrp, 10) == 0);
+  assert(errstrp == NULL);
+  assert(ndpi_strtonum("0", +10, -10, &errstrp, 10) == 0);
+  assert(errstrp != NULL);
+  assert(ndpi_strtonum("  -11  ", -10, +10, &errstrp, 10) == 0);
+  assert(errstrp != NULL);
+  assert(ndpi_strtonum("  -11  ", -100, +100, &errstrp, 10) == -11);
+  assert(errstrp == NULL);
+  assert(ndpi_strtonum("123abc", LLONG_MIN, LLONG_MAX, &errstrp, 10) == 123);
+  assert(errstrp == NULL);
+  assert(ndpi_strtonum("123abc", LLONG_MIN, LLONG_MAX, &errstrp, 16) == 0x123abc);
+  assert(errstrp == NULL);
+  assert(ndpi_strtonum("  0x123abc", LLONG_MIN, LLONG_MAX, &errstrp, 16) == 0x123abc);
+  assert(errstrp == NULL);
+  assert(ndpi_strtonum("ghi", -10, +10, &errstrp, 10) == 0);
+  assert(errstrp != NULL);
+}
+
+/* *********************************************** */
+
 void filterUnitTest() {
   ndpi_filter* f = ndpi_filter_alloc();
   u_int32_t v, i;
@@ -5628,6 +5651,7 @@ int main(int argc, char **argv) {
     ndpi_self_check_host_match(stderr);
     analysisUnitTest();
     compressedBitmapUnitTest();
+    strtonumUnitTest();
 #endif
   }
 
diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index 7238b04b3..b20305e33 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -2209,6 +2209,7 @@ extern "C" {
 
   /* ******************************* */
 
+  int64_t ndpi_strtonum(const char *numstr, int64_t minval, int64_t maxval, const char **errstrp, int base);
   int ndpi_vsnprintf(char * str, size_t size, char const * format, va_list va_args);
   int ndpi_snprintf(char * str, size_t size, char const * format, ...);
   struct tm *ndpi_gmtime_r(const time_t *timep,
diff --git a/src/lib/ndpi_utils.c b/src/lib/ndpi_utils.c
index da5727915..dd5067906 100644
--- a/src/lib/ndpi_utils.c
+++ b/src/lib/ndpi_utils.c
@@ -3065,3 +3065,40 @@ int tpkt_verify_hdr(const struct ndpi_packet_struct * const packet)
           (packet->payload[0] == 3) && (packet->payload[1] == 0) &&
           (get_u_int16_t(packet->payload,2) == htons(packet->payload_packet_len)));
 }
+
+/* ******************************************* */
+
+int64_t ndpi_strtonum(const char *numstr, int64_t minval, int64_t maxval, const char **errstrp, int base)
+{
+  int64_t val = 0;
+  char* endptr;
+
+  if (minval > maxval) {
+    *errstrp = "minval > maxval";
+    return 0;
+  }
+
+  errno = 0;    /* To distinguish success/failure after call */
+  val = (int64_t)strtoll(numstr, &endptr, base);
+
+  if((val == LLONG_MIN && errno == ERANGE) || (val < minval)) {
+    *errstrp = "value too small";
+    return 0;
+  }
+  if((val == LLONG_MAX && errno == ERANGE) || (val > maxval )) {
+    *errstrp = "value too large";
+    return 0;
+  }
+  if(errno != 0 && val == 0) {
+    *errstrp = "generic error";
+    return 0;
+  }
+  if(endptr == numstr) {
+    *errstrp = "No digits were found";
+    return 0;
+  }
+  /* Like the original strtonum, we allow further characters after the number */
+
+  *errstrp = NULL;
+  return val;
+}