+int32 read_varint(int f)
+{
+ union {
+ char b[5];
+ int32 x;
+ } u;
+ uchar ch;
+ int extra;
+
+ u.x = 0;
+ readfd(f, (char*)&ch, 1);
+ extra = int_byte_extra[ch / 4];
+ if (extra) {
+ uchar bit = ((uchar)1<<(8-extra));
+ if (extra >= (int)sizeof u.b) {
+ rprintf(FERROR, "Overflow in read_varint()\n");
+ exit_cleanup(RERR_STREAMIO);
+ }
+ readfd(f, u.b, extra);
+ u.b[extra] = ch & (bit-1);
+ } else
+ u.b[0] = ch;
+#if CAREFUL_ALIGNMENT
+ u.x = IVAL(u.b,0);
+#endif
+#if SIZEOF_INT32 > 4
+ if (u.x & (int32)0x80000000)
+ u.x |= ~(int32)0xffffffff;
+#endif
+ return u.x;
+}
+
+int64 read_varlong(int f, uchar min_bytes)
+{
+ union {
+ char b[9];
+ int64 x;
+ } u;
+ char b2[8];
+ int extra;
+
+#if SIZEOF_INT64 < 8
+ memset(u.b, 0, 8);
+#else
+ u.x = 0;
+#endif
+ readfd(f, b2, min_bytes);
+ memcpy(u.b, b2+1, min_bytes-1);
+ extra = int_byte_extra[CVAL(b2, 0) / 4];
+ if (extra) {
+ uchar bit = ((uchar)1<<(8-extra));
+ if (min_bytes + extra > (int)sizeof u.b) {
+ rprintf(FERROR, "Overflow in read_varlong()\n");
+ exit_cleanup(RERR_STREAMIO);
+ }
+ readfd(f, u.b + min_bytes - 1, extra);
+ u.b[min_bytes + extra - 1] = CVAL(b2, 0) & (bit-1);
+#if SIZEOF_INT64 < 8
+ if (min_bytes + extra > 5 || u.b[4] || CVAL(u.b,3) & 0x80) {
+ rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
+ exit_cleanup(RERR_UNSUPPORTED);
+ }
+#endif
+ } else
+ u.b[min_bytes + extra - 1] = CVAL(b2, 0);
+#if SIZEOF_INT64 < 8
+ u.x = IVAL(u.b,0);
+#elif CAREFUL_ALIGNMENT
+ u.x = IVAL(u.b,0) | (((int64)IVAL(u.b,4))<<32);
+#endif
+ return u.x;
+}
+