From 747a2576164e5f15f4f2a664f0608214cc13fc78 Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Sun, 26 Oct 2025 09:34:45 +0100
Subject: [PATCH] enhance: Add util::Bytes::push_back method

---
 src/ccache/util/bytes.cpp    | 10 +++++++
 src/ccache/util/bytes.hpp    |  2 ++
 unittest/test_util_bytes.cpp | 55 ++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/src/ccache/util/bytes.cpp b/src/ccache/util/bytes.cpp
index d3c82f43..e4f54630 100644
--- a/src/ccache/util/bytes.cpp
+++ b/src/ccache/util/bytes.cpp
@@ -158,6 +158,16 @@ Bytes::insert(const uint8_t* pos,
   m_size += inserted_size;
 }
 
+void
+Bytes::push_back(uint8_t value) noexcept
+{
+  if (m_size >= m_capacity) {
+    reserve(m_capacity == 0 ? 1 : 2 * m_capacity);
+  }
+  m_data[m_size] = value;
+  ++m_size;
+}
+
 void
 Bytes::resize(size_t size) noexcept
 {
diff --git a/src/ccache/util/bytes.hpp b/src/ccache/util/bytes.hpp
index 56d394f3..2780de07 100644
--- a/src/ccache/util/bytes.hpp
+++ b/src/ccache/util/bytes.hpp
@@ -85,6 +85,8 @@ public:
   void clear() noexcept;
   void resize(size_t size) noexcept; // Note: New bytes will be uninitialized.
 
+  void push_back(uint8_t value) noexcept;
+
   void insert(const uint8_t* pos,
               const uint8_t* first,
               const uint8_t* last) noexcept;
diff --git a/unittest/test_util_bytes.cpp b/unittest/test_util_bytes.cpp
index cc3bf3d6..2ea2f6b8 100644
--- a/unittest/test_util_bytes.cpp
+++ b/unittest/test_util_bytes.cpp
@@ -551,6 +551,61 @@ TEST_CASE("Basics")
     CHECK(bytes2[0] == 'x');
     CHECK(bytes2[1] == 'z');
   }
+
+  SUBCASE("Push to back")
+  {
+    // Push to empty bytes
+    Bytes bytes2;
+    CHECK(bytes2.size() == 0);
+    CHECK(bytes2.capacity() == 0);
+
+    bytes2.push_back('a');
+    REQUIRE(bytes2.size() == 1);
+    CHECK(bytes2.capacity() == 1);
+    CHECK(bytes2[0] == 'a');
+
+    // Push to non-empty bytes without reallocation
+    bytes2.push_back('b');
+    REQUIRE(bytes2.size() == 2);
+    CHECK(bytes2.capacity() == 2);
+    CHECK(bytes2[0] == 'a');
+    CHECK(bytes2[1] == 'b');
+
+    bytes2.push_back('c');
+    REQUIRE(bytes2.size() == 3);
+    CHECK(bytes2.capacity() == 4);
+    CHECK(bytes2[0] == 'a');
+    CHECK(bytes2[1] == 'b');
+    CHECK(bytes2[2] == 'c');
+
+    // Push multiple items to trigger reallocation
+    for (uint8_t i = 0; i < 10; ++i) {
+      bytes2.push_back(i);
+    }
+    REQUIRE(bytes2.size() == 13);
+    CHECK(bytes2.capacity() == 16);
+    CHECK(bytes2[0] == 'a');
+    CHECK(bytes2[1] == 'b');
+    CHECK(bytes2[2] == 'c');
+    CHECK(bytes2[3] == 0);
+    CHECK(bytes2[4] == 1);
+    CHECK(bytes2[12] == 9);
+
+    // Push to bytes with reserved capacity
+    Bytes bytes3;
+    bytes3.reserve(10);
+    CHECK(bytes3.capacity() == 10);
+    CHECK(bytes3.size() == 0);
+
+    for (uint8_t i = 0; i < 5; ++i) {
+      bytes3.push_back(i);
+    }
+    REQUIRE(bytes3.size() == 5);
+    CHECK(bytes3.capacity() == 10); // Should not reallocate
+    for (size_t i = 0; i < 5; ++i) {
+      CHECK(bytes3[i] == i);
+    }
+  }
 }
 
 TEST_CASE("Conversion to span")
-- 
2.47.3