diff --git a/include/stdex/stream.hpp b/include/stdex/stream.hpp
index a1ecd1905..5a9b93fee 100644
--- a/include/stdex/stream.hpp
+++ b/include/stdex/stream.hpp
@@ -1,4 +1,4 @@
-/*
+/*
 	SPDX-License-Identifier: MIT
 	Copyright © 2023-2025 Amebis
 */
@@ -73,7 +73,8 @@ namespace stdex
 		constexpr fsize_t fsize_max = UINT64_MAX;
 
 		constexpr size_t iterate_count = 0x10;
-		constexpr size_t default_block_size = 0x10000; ///< Amount of space used by copy or reallocation increments
+		constexpr int default_block_pow = 16; ///< Copy or reallocation increments use 2^default_block_pow blocks
+		constexpr size_t default_block_size = 1 << default_block_pow; ///< Amount of space used by copy or reallocation increments
 		constexpr utf16_t utf16_bom = u'\ufeff'; ///< Byte-order-mark written at each UTF-16 file start
 		constexpr utf32_t utf32_bom = U'\ufeff'; ///< Byte-order-mark written at each UTF-32 file start
 		constexpr const char utf8_bom[3] = { '\xef', '\xbb', '\xbf' }; ///> UTF-8 byte-order-mark
@@ -3451,7 +3452,13 @@ namespace stdex
 					m_state = state_t::fail;
 					return;
 				}
-				size_t reserved = tight ? required : ((required + required / 4 + (default_block_size - 1)) / default_block_size) * default_block_size;
+				size_t reserved;
+				if (tight)
+					reserved = required;
+				else {
+					reserved = stdex::add(required, required >> 2);
+					reserved = stdex::align_up(reserved, default_block_pow);
+				}
 				auto data = reinterpret_cast<uint8_t*>(realloc(m_data, reserved));
 				if (!data && reserved) _Unlikely_ {
 					m_state = state_t::fail;
@@ -3600,7 +3607,7 @@ namespace stdex
 					data = 0;
 					return *this;
 				}
-				size_t end_offset = m_offset + sizeof(T);
+				size_t end_offset = stdex::add(m_offset, sizeof(T));
 				if (end_offset <= m_size) {
 					data = LE2HE(*reinterpret_cast<T*>(&m_data[m_offset]));
 					m_offset = end_offset;
@@ -3640,7 +3647,7 @@ namespace stdex
 					data.clear();
 					return *this;
 				}
-				size_t end_offset = m_offset + sizeof(uint32_t);
+				size_t end_offset = stdex::add(m_offset, sizeof(uint32_t));
 				if (end_offset <= m_size) {
 					uint32_t num_chars = LE2HE(*reinterpret_cast<uint32_t*>(&m_data[m_offset]));
 					m_offset = end_offset;
@@ -3669,7 +3676,7 @@ namespace stdex
 #if SET_FILE_OP_TIMES
 				m_atime = m_mtime = time_point::now();
 #endif
-				size_t end_offset = m_offset + length;
+				size_t end_offset = stdex::add(m_offset, length);
 				if (end_offset > m_reserved) {
 					reserve(end_offset);
 					if (!ok()) _Unlikely_
@@ -3691,7 +3698,7 @@ namespace stdex
 #if SET_FILE_OP_TIMES
 				m_atime = m_mtime = time_point::now();
 #endif
-				size_t end_offset = m_offset + amount;
+				size_t end_offset = stdex::add(m_offset, amount);
 				if (end_offset > m_reserved) {
 					reserve(end_offset);
 					if (!ok()) _Unlikely_
@@ -3726,7 +3733,7 @@ namespace stdex
 #endif
 				if (CHECK_STREAM_STATE && !ok()) _Unlikely_
 					return *this;
-				size_t end_offset = m_offset + sizeof(T);
+				size_t end_offset = stdex::add(m_offset, sizeof(T));
 				if (end_offset > m_reserved) {
 					reserve(end_offset);
 					if (!ok()) _Unlikely_
@@ -3767,9 +3774,9 @@ namespace stdex
 				size_t num_chars = stdex::strlen(data);
 				if (num_chars > UINT32_MAX)
 					throw std::invalid_argument("string too long");
-				size_t size_chars = num_chars * sizeof(T);
-				size_t size = sizeof(uint32_t) + size_chars;
-				size_t end_offset = m_offset + size;
+				size_t size_chars = stdex::mul(num_chars, sizeof(T));
+				size_t size = stdex::add(sizeof(uint32_t), size_chars);
+				size_t end_offset = stdex::add(m_offset, size);
 				if (end_offset > m_reserved) {
 					reserve(end_offset);
 					if (!ok()) _Unlikely_
@@ -3812,9 +3819,9 @@ namespace stdex
 				size_t num_chars = data.size();
 				if (num_chars > UINT32_MAX)
 					throw std::invalid_argument("string too long");
-				size_t size_chars = num_chars * sizeof(T);
-				size_t size = sizeof(uint32_t) + size_chars;
-				size_t end_offset = m_offset + size;
+				size_t size_chars = stdex::mul(num_chars, sizeof(T));
+				size_t size = stdex::add(sizeof(uint32_t), size_chars);
+				size_t end_offset = stdex::add(m_offset, size);
 				if (end_offset > m_reserved) {
 					reserve(end_offset);
 					if (!ok()) _Unlikely_