From f1e894aefd395b9be608e56998ff0a3cd4223f55 Mon Sep 17 00:00:00 2001
From: Simon Rozman <simon@rozman.si>
Date: Thu, 5 Jun 2025 12:27:54 +0200
Subject: [PATCH] stream: read huge data in blocks on POSIX

read() blocks when there is no more data to read. However, we do need
to loop when read is divided into blocks.

Signed-off-by: Simon Rozman <simon@rozman.si>
---
 include/stdex/stream.hpp | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/include/stdex/stream.hpp b/include/stdex/stream.hpp
index e8dab8759..a35001429 100644
--- a/include/stdex/stream.hpp
+++ b/include/stdex/stream.hpp
@@ -2260,17 +2260,19 @@ namespace stdex
 					reinterpret_cast<uint8_t*&>(data) += num_read;
 				}
 #else
-				auto num_read = ::read(m_h, data, length);
-				if (num_read < 0) _Unlikely_ {
-					m_state = state_t::fail;
-					return 0;
+				for (size_t to_read = length;;) {
+					auto num_read = ::read(m_h, data, std::min<size_t>(to_read, SSIZE_MAX));
+					if (num_read < 0) _Unlikely_ {
+						m_state = to_read < length ? state_t::ok : state_t::fail;
+						return length - to_read;
+					}
+					to_read -= static_cast<size_t>(num_read);
+					if (num_read < SSIZE_MAX) {
+						m_state = to_read < length || !length ? state_t::ok : state_t::eof;
+						return length - to_read;
+					}
+					reinterpret_cast<uint8_t*&>(data) += num_read;
 				}
-				if (!num_read) _Unlikely_ {
-					m_state = !length ? state_t::ok : state_t::eof;
-					return 0;
-				}
-				m_state = state_t::ok;
-				return num_read;
 #endif
 			}