branches/zip: Add debug assertions about page_zip->m_end < paeg_zip->m_size.

page/page0zip.c

@@ -1851,6 +1851,7 @@ zlib_done:
 			goto err_exit;
 		}
 		page_zip->m_end = mod_log_ptr - page_zip->data;
+		ut_ad(page_zip->m_end < page_zip->size);
 	}
 
 	if (UNIV_UNLIKELY(!page_zip_set_extra_bytes(
@@ -2292,6 +2293,7 @@ page_zip_write_rec(
 	}
 
 	ut_a(!*data);
+	ut_ad((ulint) (data - page_zip->data) < page_zip->size);
 	page_zip->m_end = data - page_zip->data;
 
 #ifdef UNIV_ZIP_DEBUG
@@ -2700,6 +2702,7 @@ page_zip_clear_rec(
 		}
 		*data++ = (heap_no - 1) << 1 | 1;
 		ut_ad(!*data);
+		ut_ad((ulint) (data - page_zip->data) < page_zip->size);
 		page_zip->m_end = data - page_zip->data;
 #ifdef UNIV_ZIP_DEBUG
 		ut_a(page_zip_validate(page_zip, page));
@@ -3125,6 +3128,7 @@ page_zip_copy(
 	page_zip->n_blobs = src_zip->n_blobs;
 	page_zip->m_start = src_zip->m_start;
 	page_zip->m_end = src_zip->m_end;
+	ut_ad(page_zip->m_end < page_zip->size);
 
 	if (!page_is_leaf(src)
 			&& UNIV_UNLIKELY(mach_read_from_4((byte*) src