From a9531c86a433c8b7ae1f77ff0266c27c39eca7f4 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Fri, 10 Mar 2023 11:28:33 +1100
Subject: mostly single task pipeline

---
 src/memory/include/himem.hpp | 78 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 src/memory/include/himem.hpp

(limited to 'src/memory/include')

diff --git a/src/memory/include/himem.hpp b/src/memory/include/himem.hpp
new file mode 100644
index 00000000..c65091d7
--- /dev/null
+++ b/src/memory/include/himem.hpp
@@ -0,0 +1,78 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+#include "esp32/himem.h"
+#include "span.hpp"
+
+/*
+ * Wrapper around an ESP-IDF himem allocation, which uses RAII to clean up after
+ * itself.
+ */
+template <std::size_t size>
+class HimemAlloc {
+ public:
+  esp_himem_handle_t handle;
+  const bool is_valid;
+
+  HimemAlloc() : is_valid(esp_himem_alloc(size, &handle) == ESP_OK) {}
+
+  ~HimemAlloc() {
+    if (is_valid) {
+      esp_himem_free(handle);
+    }
+  }
+
+  // Not copyable or movable.
+  HimemAlloc(const HimemAlloc&) = delete;
+  HimemAlloc& operator=(const HimemAlloc&) = delete;
+};
+
+/*
+ * Wrapper around an ESP-IDF himem allocation, which maps a HimemAlloc into the
+ * usable address space. Instances always contain the last memory region that
+ * was mapped within them.
+ */
+template <std::size_t size>
+class MappableRegion {
+ private:
+  std::byte* bytes_;
+
+ public:
+  esp_himem_rangehandle_t range_handle;
+  const bool is_valid;
+
+  MappableRegion()
+      : bytes_(nullptr),
+        is_valid(esp_himem_alloc_map_range(size, &range_handle) == ESP_OK) {}
+
+  ~MappableRegion() {
+    if (bytes_ != nullptr) {
+      esp_himem_unmap(range_handle, bytes_, size);
+    }
+    if (is_valid) {
+      esp_himem_free_map_range(range_handle);
+    }
+  }
+
+  auto Get() -> cpp::span<std::byte> {
+    if (bytes_ != nullptr) {
+      return {};
+    }
+    return {bytes_, size};
+  }
+
+  auto Map(const HimemAlloc<size> &alloc) -> cpp::span<std::byte> {
+    if (bytes_ != nullptr) {
+      ESP_ERROR_CHECK(esp_himem_unmap(range_handle, bytes_, size));
+    }
+    ESP_ERROR_CHECK(esp_himem_map(alloc.handle, range_handle, 0, 0, size, 0,
+                                  reinterpret_cast<void**>(&bytes_)));
+    return Get();
+  }
+
+  // Not copyable or movable.
+  MappableRegion(const MappableRegion&) = delete;
+  MappableRegion& operator=(const MappableRegion&) = delete;
+};
-- 
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