Add nghttp2_bufs_realloc

lib/nghttp2_buf.c

@@ -169,6 +169,33 @@ int nghttp2_bufs_init3(nghttp2_bufs *bufs, size_t chunk_length,
   return 0;
 }
 
+int nghttp2_bufs_realloc(nghttp2_bufs *bufs, size_t chunk_length)
+{
+  int rv;
+  nghttp2_buf_chain *chain;
+
+  if(chunk_length < bufs->offset) {
+    return NGHTTP2_ERR_INVALID_ARGUMENT;
+  }
+
+  rv = buf_chain_new(&chain, chunk_length);
+  if(rv != 0) {
+    return rv;
+  }
+
+  nghttp2_bufs_free(bufs);
+
+  bufs->head = chain;
+  bufs->cur = bufs->head;
+
+  nghttp2_buf_shift_right(&bufs->cur->buf, bufs->offset);
+
+  bufs->chunk_length = chunk_length;
+  bufs->chunk_used = 1;
+
+  return 0;
+}
+
 void nghttp2_bufs_free(nghttp2_bufs *bufs)
 {
   nghttp2_buf_chain *chain, *next_chain;

lib/nghttp2_buf.h

@@ -228,6 +228,22 @@ int nghttp2_bufs_wrap_init(nghttp2_bufs *bufs, uint8_t *begin, size_t len);
  */
 void nghttp2_bufs_wrap_free(nghttp2_bufs *bufs);
 
+/*
+ * Reallocates internal buffer using |chunk_length|.  The max_chunk,
+ * chunk_keep and offset do not change.  After successful allocation
+ * of new buffer, previous buffers are deallocated without copying
+ * anything into new buffers.  chunk_used is reset to 1.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_NOMEM
+ *     Out of memory.
+ * NGHTTP2_ERR_INVALID_ARGUMENT
+ *     chunk_length < offset
+ */
+int nghttp2_bufs_realloc(nghttp2_bufs *bufs, size_t chunk_length);
+
 /*
  * Appends the |data| of length |len| to the |bufs|. The write starts
  * at bufs->cur->buf.last. A new buffers will be allocated to store

tests/main.c

@@ -302,7 +302,8 @@ int main(int argc, char* argv[])
       !CU_add_test(pSuite, "bufs_seek_present",
                    test_nghttp2_bufs_seek_last_present) ||
       !CU_add_test(pSuite, "bufs_next_present",
-                   test_nghttp2_bufs_next_present)
+                   test_nghttp2_bufs_next_present) ||
+      !CU_add_test(pSuite, "bufs_realloc", test_nghttp2_bufs_realloc)
       ) {
      CU_cleanup_registry();
      return CU_get_error();

tests/nghttp2_buf_test.c

@@ -317,3 +317,27 @@ void test_nghttp2_bufs_next_present(void)
 
   nghttp2_bufs_free(&bufs);
 }
+
+void test_nghttp2_bufs_realloc(void)
+{
+  int rv;
+  nghttp2_bufs bufs;
+
+  rv = nghttp2_bufs_init3(&bufs, 266, 3, 1, 10);
+  CU_ASSERT(0 == rv);
+
+  /* Create new buffer to see that these buffers are deallocated on
+     realloc */
+  rv = nghttp2_bufs_advance(&bufs);
+  CU_ASSERT(0 == rv);
+
+  rv = nghttp2_bufs_realloc(&bufs, 522);
+  CU_ASSERT(0 == rv);
+
+  CU_ASSERT(512 == nghttp2_bufs_cur_avail(&bufs));
+
+  rv = nghttp2_bufs_realloc(&bufs, 9);
+  CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT == rv);
+
+  nghttp2_bufs_free(&bufs);
+}

tests/nghttp2_buf_test.h

@@ -33,5 +33,6 @@ void test_nghttp2_bufs_reset(void);
 void test_nghttp2_bufs_advance(void);
 void test_nghttp2_bufs_seek_last_present(void);
 void test_nghttp2_bufs_next_present(void);
+void test_nghttp2_bufs_realloc(void);
 
 #endif /* NGHTTP2_BUF_TEST_H */