Tests and fixes to bugs that the tests found.

tests.c

@@ -0,0 +1,56 @@
+#include <assert.h>
+#include <stdio.h>
+#include "pbstream.c"
+
+void test_get_varint()
+{
+  enum pbstream_status status;
+
+  char zero[] = {0x00};
+  char *zero_buf = zero;
+  uint64_t zero_val;
+  status = get_varint(&zero_buf, zero_buf+sizeof(zero), &zero_val);
+  assert(status == PBSTREAM_STATUS_OK);
+  assert(zero_val == 0);
+  assert(zero_buf == zero + sizeof(zero));
+
+  char one[] = {0x01};
+  char *one_buf = one;
+  uint64_t one_val;
+  status = get_varint(&one_buf, one_buf+sizeof(one), &one_val);
+  assert(status == PBSTREAM_STATUS_OK);
+  assert(one_val == 1);
+
+  char twobyte[] = {0xAC, 0x02};
+  char *twobyte_buf = twobyte;
+  uint64_t twobyte_val;
+  status = get_varint(&twobyte_buf, twobyte_buf+sizeof(twobyte), &twobyte_val);
+  assert(status == PBSTREAM_STATUS_OK);
+  assert(twobyte_val == 300);
+
+  char ninebyte[] = {0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x7F};
+  char *ninebyte_buf = ninebyte;
+  uint64_t ninebyte_val;
+  status = get_varint(&ninebyte_buf, ninebyte_buf+sizeof(ninebyte), &ninebyte_val);
+  assert(status == PBSTREAM_STATUS_OK);
+  assert(ninebyte_val == (1LL<<63));
+
+  char overrun[] = {0x80, 0x01};
+  char *overrun_buf = overrun;
+  uint64_t overrun_val;
+  status = get_varint(&overrun_buf, overrun_buf+sizeof(overrun)-1, &overrun_val);
+  assert(status == PBSTREAM_STATUS_INCOMPLETE);
+
+  char tenbyte[] = {0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x01};
+  char *tenbyte_buf = tenbyte;
+  uint64_t tenbyte_val;
+  status = get_varint(&tenbyte_buf, tenbyte_buf+sizeof(tenbyte), &tenbyte_val);
+  assert(status == PBSTREAM_ERROR_UNTERMINATED_VARINT);
+}
+
+int main()
+{
+  test_get_varint();
+  printf("All tests passed.\n");
+  return 0;
+}