string_strim allows optionnal second argument which list the characters to strim.

m-string.h

@@ -726,20 +726,31 @@ string_hash(const string_t v)
   return m_core_hash(v->ptr, v->size);
 }
 
+// Return true if c is a character from charac
+static bool
+stringi_strim_char(char c, const char charac[])
+{
+  for(const char *s = charac; *s; s++) {
+    if (c == *s)
+      return true;
+  }
+  return false;
+}
+
 static inline void
-string_strim(string_t v)
+string_strim(string_t v, const char charac[])
 {
   STRINGI_CONTRACT (v);
   char *b = v->ptr;
   size_t size = v->size;
-  while (size > 0 && (b[size-1] == ' ' || b[size-1] == '\n' || b[size-1] == '\r' || b[size-1] == '\t'))
+  while (size > 0 && stringi_strim_char(b[size-1], charac))
     size --;
   if (size == 0) {
     v->ptr[0] = 0;
     v->size = size;
     return;
   }
-  while (*b == ' ' || *b == '\n' || *b == '\r' || *b == '\t')
+  while (stringi_strim_char(*b, charac))
     b++;
   M_ASSUME (b >= v->ptr &&  size >= (size_t) (b - v->ptr) );
   size -= (b - v->ptr);
@@ -749,6 +760,7 @@ string_strim(string_t v)
   STRINGI_CONTRACT (v);
 }
 
+
 /* I/O */
 static inline void
 string_get_str(string_t v, const string_t v2, bool append)
@@ -1136,6 +1148,9 @@ namespace m_string {
 #define string_replace(v, s1, ...)					\
   M_APPLY(string_replace, v, s1, M_IF_DEFAULT1(0, __VA_ARGS__))
 
+#define string_strim(...)                                               \
+  M_APPLY(string_strim, M_IF_DEFAULT1("  \n\r\t", __VA_ARGS__))
+
 /* Macro encapsulation for C11 */
 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
 

tests/test-mstring.c

@@ -277,6 +277,10 @@ static void test0(void)
   string_strim(s1);
   assert (string_cmp_str (s1, "") == 0);
 
+  string_set_str(s1, " \r\n\t++\t YES  ++ \n\r\t");
+  string_strim(s1, "\r\n\t +");
+  assert (string_cmp_str (s1, "YES") == 0);
+  
   string_set_str(s1, "Hello world");
   string_get_str(s2, s1, false);
   assert (string_cmp_str (s2, "\"Hello world\"") == 0);