1 files changed, 73 insertions, 0 deletions
diff --git a/sql/sql_string.cc b/sql/sql_string.cc
index 7759985ba85..7c9793b273b 100644
--- a/sql/sql_string.cc
+++ b/sql/sql_string.cc
@@ -1119,3 +1119,76 @@ void String::swap(String &s)
   swap_variables(bool, alloced, s.alloced);
   swap_variables(CHARSET_INFO*, str_charset, s.str_charset);
 }
+
+
+/**
+  Convert string to printable ASCII string
+
+  @details This function converts input string "from" replacing non-ASCII bytes
+  with hexadecimal sequences ("\xXX") optionally appending "..." to the end of
+  the resulting string.
+  This function used in the ER_TRUNCATED_WRONG_VALUE_FOR_FIELD error messages,
+  e.g. when a string cannot be converted to a result charset.
+
+
+  @param    to          output buffer
+  @param    to_len      size of the output buffer (8 bytes or greater)
+  @param    from        input string
+  @param    from_len    size of the input string
+  @param    from_cs     input charset
+  @param    nbytes      maximal number of bytes to convert (from_len if 0)
+
+  @return   number of bytes in the output string
+*/
+
+uint convert_to_printable(char *to, size_t to_len,
+                          const char *from, size_t from_len,
+                          CHARSET_INFO *from_cs, size_t nbytes /*= 0*/)
+{
+  /* needs at least 8 bytes for '\xXX...' and zero byte */
+  DBUG_ASSERT(to_len >= 8);
+
+  char *t= to;
+  char *t_end= to + to_len - 1; // '- 1' is for the '\0' at the end
+  const char *f= from;
+  const char *f_end= from + (nbytes ? min(from_len, nbytes) : from_len);
+  char *dots= to; // last safe place to append '...'
+
+  if (!f || t == t_end)
+    return 0;
+
+  for (; t < t_end && f < f_end; f++)
+  {
+    /*
+      If the source string is ASCII compatible (mbminlen==1)
+      and the source character is in ASCII printable range (0x20..0x7F),
+      then display the character as is.
+      
+      Otherwise, if the source string is not ASCII compatible (e.g. UCS2),
+      or the source character is not in the printable range,
+      then print the character using HEX notation.
+    */
+    if (((unsigned char) *f) >= 0x20 &&
+        ((unsigned char) *f) <= 0x7F &&
+        from_cs->mbminlen == 1)
+    {
+      *t++= *f;
+    }
+    else
+    {
+      if (t_end - t < 4) // \xXX
+        break;
+      *t++= '\\';
+      *t++= 'x';
+      *t++= _dig_vec_upper[((unsigned char) *f) >> 4];
+      *t++= _dig_vec_upper[((unsigned char) *f) & 0x0F];
+    }
+    if (t_end - t >= 3) // '...'
+      dots= t;
+  }
+  if (f < from + from_len)
+    memcpy(dots, STRING_WITH_LEN("...\0"));
+  else
+    *t= '\0';
+  return t - to;
+}