text: #include "buffer.h"
  
  void ab_append(append_buf* ab, const char* s, int len) {
    char *new = realloc(ab->b, ((unsigned long) ab->len + (unsigned long) len)*sizeof(char));
    if (new == NULL) return;
    memcpy(&new[ab->len], s, len);
    ab->b = new;
    ab->len += len;
  }
  
  void ab_free(append_buf* ab) {
    free(ab->b);
  }
  