From 9d3b65ba5cdaa6285292301ec89a37fec3f10e58 Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Thu, 23 Oct 2025 10:13:24 +0200
Subject: [PATCH] enhance: Add Bytes::erase

---
 src/ccache/util/bytes.cpp    | 21 ++++++++
 src/ccache/util/bytes.hpp    |  3 ++
 unittest/test_util_bytes.cpp | 92 ++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+)

diff --git a/src/ccache/util/bytes.cpp b/src/ccache/util/bytes.cpp
index 7524d991..b3e01fee 100644
--- a/src/ccache/util/bytes.cpp
+++ b/src/ccache/util/bytes.cpp
@@ -131,4 +131,25 @@ Bytes::resize(size_t size) noexcept
   m_size = size;
 }
 
+void
+Bytes::erase(const uint8_t* pos, const size_t size) noexcept
+{
+  if (size == 0) {
+    return;
+  }
+  const size_t offset = pos - m_data.get();
+  if (offset + size < m_size) {
+    std::memmove(m_data.get() + offset,
+                 m_data.get() + offset + size,
+                 m_size - offset - size);
+  }
+  m_size -= size;
+}
+
+void
+Bytes::erase(const uint8_t* first, const uint8_t* last) noexcept
+{
+  erase(first, last - first);
+}
+
 } // namespace util
diff --git a/src/ccache/util/bytes.hpp b/src/ccache/util/bytes.hpp
index c103ed22..327e0c6e 100644
--- a/src/ccache/util/bytes.hpp
+++ b/src/ccache/util/bytes.hpp
@@ -86,6 +86,9 @@ public:
   void insert(const uint8_t* pos, const char* data, size_t size) noexcept;
   void insert(const uint8_t* pos, nonstd::span<const uint8_t> data) noexcept;
 
+  void erase(const uint8_t* pos, const size_t size) noexcept;
+  void erase(const uint8_t* first, const uint8_t* last) noexcept;
+
 private:
   std::unique_ptr<uint8_t[]> m_data;
   size_t m_size = 0;
diff --git a/unittest/test_util_bytes.cpp b/unittest/test_util_bytes.cpp
index cb564c88..11c6927e 100644
--- a/unittest/test_util_bytes.cpp
+++ b/unittest/test_util_bytes.cpp
@@ -397,6 +397,98 @@ TEST_CASE("Basics")
     CHECK(bytes2[1] == 'b');
     CHECK(bytes2[2] == 'c');
   }
+
+  SUBCASE("Erase with pos and size")
+  {
+    Bytes bytes2("abcdef", 6);
+
+    // Erase from beginning
+    bytes2.erase(bytes2.begin(), 2);
+    REQUIRE(bytes2.size() == 4);
+    CHECK(bytes2[0] == 'c');
+    CHECK(bytes2[1] == 'd');
+    CHECK(bytes2[2] == 'e');
+    CHECK(bytes2[3] == 'f');
+
+    // Erase from middle
+    bytes2.erase(bytes2.begin() + 1, 2);
+    REQUIRE(bytes2.size() == 2);
+    CHECK(bytes2[0] == 'c');
+    CHECK(bytes2[1] == 'f');
+
+    // Erase from end
+    bytes2.erase(bytes2.begin() + 1, 1);
+    REQUIRE(bytes2.size() == 1);
+    CHECK(bytes2[0] == 'c');
+
+    // Erase remaining
+    bytes2.erase(bytes2.begin(), 1);
+    REQUIRE(bytes2.size() == 0);
+    CHECK(bytes2.empty());
+  }
+
+  SUBCASE("Erase with first and last")
+  {
+    Bytes bytes2("0123456789", 10);
+
+    // Erase from beginning
+    bytes2.erase(bytes2.begin(), bytes2.begin() + 3);
+    REQUIRE(bytes2.size() == 7);
+    CHECK(bytes2[0] == '3');
+    CHECK(bytes2[1] == '4');
+    CHECK(bytes2[6] == '9');
+
+    // Erase from middle
+    bytes2.erase(bytes2.begin() + 2, bytes2.begin() + 5);
+    REQUIRE(bytes2.size() == 4);
+    CHECK(bytes2[0] == '3');
+    CHECK(bytes2[1] == '4');
+    CHECK(bytes2[2] == '8');
+    CHECK(bytes2[3] == '9');
+
+    // Erase from end
+    bytes2.erase(bytes2.begin() + 2, bytes2.end());
+    REQUIRE(bytes2.size() == 2);
+    CHECK(bytes2[0] == '3');
+    CHECK(bytes2[1] == '4');
+
+    // Erase all
+    bytes2.erase(bytes2.begin(), bytes2.end());
+    REQUIRE(bytes2.size() == 0);
+    CHECK(bytes2.empty());
+  }
+
+  SUBCASE("Erase zero bytes")
+  {
+    Bytes bytes2("abc", 3);
+    const uint8_t* orig_data = bytes2.data();
+
+    // Erase zero with pos and size
+    bytes2.erase(bytes2.begin(), size_t(0));
+    REQUIRE(bytes2.size() == 3);
+    CHECK(bytes2.data() == orig_data);
+    CHECK(bytes2[0] == 'a');
+    CHECK(bytes2[1] == 'b');
+    CHECK(bytes2[2] == 'c');
+
+    // Erase zero with first and last
+    bytes2.erase(bytes2.begin(), bytes2.begin());
+    REQUIRE(bytes2.size() == 3);
+    CHECK(bytes2.data() == orig_data);
+    CHECK(bytes2[0] == 'a');
+    CHECK(bytes2[1] == 'b');
+    CHECK(bytes2[2] == 'c');
+  }
+
+  SUBCASE("Erase single byte")
+  {
+    Bytes bytes2("xyz", 3);
+
+    bytes2.erase(bytes2.begin() + 1, bytes2.begin() + 2);
+    REQUIRE(bytes2.size() == 2);
+    CHECK(bytes2[0] == 'x');
+    CHECK(bytes2[1] == 'z');
+  }
 }
 
 TEST_CASE("Conversion to span")
-- 
2.47.3