* add functions to evaluate utf8 strings as described at the instructables

diff --git a/libcitadel/lib/libcitadel.h b/libcitadel/lib/libcitadel.h
index 90bbb3530c8a3f10bf908a587683a5ffd866d140..6eab11acecdbf04fe1d5ec7d9f67d0dc992d8ec1 100644 (file)
--- a/libcitadel/lib/libcitadel.h
+++ b/libcitadel/lib/libcitadel.h
@@ -186,6 +186,10 @@ void ShutDownLibCitadel(void);
 
 /* tools */
 
+int Ctdl_IsUtf8SequenceStart(char Char);
+int Ctdl_GetUtf8SequenceLength(char Char);
+int Ctdl_Utf8StrLen(char *str);
+char *Ctdl_Utf8StrCut(char *str, int maxlen);
 
 
 int safestrncpy(char *dest, const char *src, size_t n);

diff --git a/libcitadel/lib/tools.c b/libcitadel/lib/tools.c
index dd630420fa4b79b57ded590ddcab02414e5192dd..15e346778aad74a2c3909c3425c5f39a9844667a 100644 (file)
--- a/libcitadel/lib/tools.c
+++ b/libcitadel/lib/tools.c
@@ -919,6 +919,97 @@ void stripltlen(char *buf, int *len)
        }
 }
 
+/**
+ * \brief detect whether this char starts an utf-8 encoded char
+ * \param Char character to inspect
+ * \returns yes or no
+ */
+inline int Ctdl_IsUtf8SequenceStart(char Char)
+{
+/** 11??.???? indicates an UTF8 Sequence. */
+       return ((Char & 0xC0) != 0);
+}
+
+/**
+ * \brief evaluate the length of an utf8 special character sequence
+ * \param Char the character to examine
+ * \returns width of utf8 chars in bytes
+ */
+inline int Ctdl_GetUtf8SequenceLength(char Char)
+{
+       int n = 1;
+        char test = (1<<7);
+       
+       while ((n < 8) && ((test & Char) != 0)) {
+               test = test << 1;
+               n ++;
+       }
+       if (n > 6)
+               n = 1;
+       return n;
+}
+
+/**
+ * \brief measure the number of glyphs in an UTF8 string...
+ * \param str string to measure
+ * \returns the length of str
+ */
+int Ctdl_Utf8StrLen(char *str)
+{
+       int n = 0;
+       int m = 0;
+       char *aptr;
+
+       if (str == NULL)
+               return n;
+       aptr = str;
+       while (*aptr != '\0') {
+               if (Ctdl_IsUtf8SequenceStart(*aptr)){
+                       m = Ctdl_GetUtf8SequenceLength(*aptr);
+                       while ((m-- > 0) && (*aptr++ != '\0'))
+                               n ++;
+               }
+               else {
+                       n++;
+                       aptr++;
+               }
+                       
+       }
+       return n;
+}
+
+/**
+ * \brief cuts a string after maxlen glyphs
+ * \param str string to cut to maxlen glyphs
+ * \param maxlen how long may the string become?
+ * \returns pointer to maxlen or the end of the string
+ */
+char *Ctdl_Utf8StrCut(char *str, int maxlen)
+{
+       int n, m = 0;
+       char *aptr;
+
+       if (str == NULL)
+               return NULL;
+       aptr = str;
+       while (*aptr != '\0') {
+               if (Ctdl_IsUtf8SequenceStart(*aptr)){
+                       m = Ctdl_GetUtf8SequenceLength(*aptr);
+                       while ((m-- > 0) && (*aptr++ != '\0'))
+                               n ++;
+               }
+               else {
+                       n++;
+                       aptr++;
+               }
+               if (n > maxlen) {
+                       *aptr = '\0';
+                       return aptr;
+               }                       
+       }
+       return aptr;
+}
+
 
 /*
  * Convert all whitespace characters in a supplied string to underscores
@@ -937,3 +1028,4 @@ void convert_spaces_to_underscores(char *str)
                }
        }
 }
+