+/* iconv_carefully_1 is like iconv_carefully, except that it stops after
+ converting one character. */
+static size_t
+iconv_carefully_1 (iconv_t cd,
+ const char **inbuf, size_t *inbytesleft,
+ char **outbuf, size_t *outbytesleft,
+ bool *incremented)
+{
+ const char *inptr = *inbuf;
+ const char *inptr_end = inptr + *inbytesleft;
+ char *outptr = *outbuf;
+ size_t outsize = *outbytesleft;
+ const char *inptr_before = inptr;
+ size_t res = (size_t)(-1);
+ size_t insize;
+
+ for (insize = 1; inptr + insize <= inptr_end; insize++)
+ {
+ res = iconv (cd,
+ (ICONV_CONST char **) &inptr, &insize,
+ &outptr, &outsize);
+ if (!(res == (size_t)(-1) && errno == EINVAL))
+ break;
+ /* We expect that no input bytes have been consumed so far. */
+ if (inptr != inptr_before)
+ abort ();
+ }
+
+ *inbuf = inptr;
+ *inbytesleft = inptr_end - inptr;
+# if !defined _LIBICONV_VERSION && !defined __GLIBC__
+ /* Irix iconv() inserts a NUL byte if it cannot convert.
+ NetBSD iconv() inserts a question mark if it cannot convert.
+ Only GNU libiconv and GNU libc are known to prefer to fail rather
+ than doing a lossy conversion. */
+ if (res != (size_t)(-1) && res > 0)
+ {
+ /* iconv() has already incremented INPTR. We cannot go back to a
+ previous INPTR, otherwise the state inside CD would become invalid,
+ if FROM_CODESET is a stateful encoding. So, tell the caller that
+ *INBUF has already been incremented. */
+ *incremented = (inptr > inptr_before);
+ errno = EILSEQ;
+ return (size_t)(-1);
+ }
+# endif
+
+ if (res != (size_t)(-1))
+ {
+ *outbuf = outptr;
+ *outbytesleft = outsize;
+ }
+ *incremented = false;
+ return res;
+}
+