93         num_preshift = 255;

   106 

   107             // time to move some bytes!

   108             memmove(dst->str + num_preshift, dst->str + index - 1, num_shift);

   109         }

   110     }

   111 

   112     // actual byte insertion

   113     memmove(dst->str + index - 1, src->str, num_insert);

   114     // store new length

   115     dst->len = num_shift + num_preshift;

   116 }

   117 

   118 void __attribute__((overloadable)) fpcrtl_insert__vars(astring *src, astring *dst, SizeInt index) {

   119     int num_insert;

   120     int num_shift;

   121     int num_preshift;

   122 

   123     // nothing to do if empty string is inserted or index invalid

   124     if ((src->len == 0) || (index < 1) || (index > MAX_ANSISTRING_LENGTH)) {

   125         return;

   126     }

   127 

   128     num_insert = src->len;

   129     // number of chars from start of destination string to end of insertion

   130     num_preshift = index - 1 + num_insert;

   131 

   132     // don't overflow on insert

   133     if (num_preshift > MAX_ANSISTRING_LENGTH) {

   134         num_preshift = MAX_ANSISTRING_LENGTH;

   135         num_insert = MAX_ANSISTRING_LENGTH - (index - 1);

   136         num_shift = 0;

   137     }

   138     // shift trailing chars

   139     else {

   140         // number of bytes to be shifted

   141         num_shift = dst->len - (index - 1);

   142 

   143         if (num_shift > 0) {

   144             // don't overflow when shifting

   145             if (num_shift + num_preshift > MAX_ANSISTRING_LENGTH)

   146                 num_shift = MAX_ANSISTRING_LENGTH - num_preshift;