1 files changed, 266 insertions, 0 deletions
diff --git a/externals/sirit/src/stream.h b/externals/sirit/src/stream.h
new file mode 100644
index 0000000000..7029b6c4e7
--- /dev/null
+++ b/externals/sirit/src/stream.h
@@ -0,0 +1,266 @@
+/* This file is part of the sirit project.
+ * Copyright (c) 2019 sirit
+ * This software may be used and distributed according to the terms of the
+ * 3-Clause BSD License
+ */
+
+#pragma once
+
+#include <bit>
+#include <cassert>
+#include <concepts>
+#include <cstddef>
+#include <functional>
+#include <string_view>
+#include <unordered_map>
+#include <variant>
+#include <vector>
+#include <utility>
+
+#ifndef __cpp_lib_bit_cast
+#include <cstring>
+#endif
+
+#include <spirv/unified1/spirv.hpp>
+
+#include "common_types.h"
+
+namespace Sirit {
+
+class Declarations;
+
+struct OpId {
+    OpId(spv::Op opcode_) : opcode{opcode_} {}
+    OpId(spv::Op opcode_, Id result_type_) : opcode{opcode_}, result_type{result_type_} {
+        assert(result_type.value != 0);
+    }
+
+    spv::Op opcode{};
+    Id result_type{};
+};
+
+struct EndOp {};
+
+inline size_t WordsInString(std::string_view string) {
+    return string.size() / sizeof(u32) + 1;
+}
+
+inline void InsertStringView(std::vector<u32>& words, size_t& insert_index,
+                             std::string_view string) {
+    const size_t size = string.size();
+    const auto read = [string, size](size_t offset) {
+        return offset < size ? static_cast<u32>(string[offset]) : 0u;
+    };
+
+    for (size_t i = 0; i < size; i += sizeof(u32)) {
+        words[insert_index++] = read(i) | read(i + 1) << 8 | read(i + 2) << 16 | read(i + 3) << 24;
+    }
+    if (size % sizeof(u32) == 0) {
+        words[insert_index++] = 0;
+    }
+}
+
+class Stream {
+    friend Declarations;
+
+public:
+    explicit Stream(u32* bound_) : bound{bound_} {}
+
+    void Reserve(size_t num_words) {
+        if (insert_index + num_words <= words.size()) {
+            return;
+        }
+        words.resize(insert_index + num_words);
+    }
+
+    std::span<const u32> Words() const noexcept {
+        return std::span(words.data(), insert_index);
+    }
+
+    u32 LocalAddress() const noexcept {
+        return static_cast<u32>(words.size());
+    }
+
+    u32 Value(u32 index) const noexcept {
+        return words[index];
+    }
+
+    void SetValue(u32 index, u32 value) noexcept {
+        words[index] = value;
+    }
+
+    Stream& operator<<(spv::Op op) {
+        op_index = insert_index;
+        words[insert_index++] = static_cast<u32>(op);
+        return *this;
+    }
+
+    Stream& operator<<(OpId op) {
+        op_index = insert_index;
+        words[insert_index++] = static_cast<u32>(op.opcode);
+        if (op.result_type.value != 0) {
+            words[insert_index++] = op.result_type.value;
+        }
+        words[insert_index++] = ++*bound;
+        return *this;
+    }
+
+    Id operator<<(EndOp) {
+        const size_t num_words = insert_index - op_index;
+        words[op_index] |= static_cast<u32>(num_words) << 16;
+        return Id{*bound};
+    }
+
+    Stream& operator<<(u32 value) {
+        words[insert_index++] = value;
+        return *this;
+    }
+
+    Stream& operator<<(s32 value) {
+        return *this << static_cast<u32>(value);
+    }
+
+    Stream& operator<<(u64 value) {
+        return *this << static_cast<u32>(value) << static_cast<u32>(value >> 32);
+    }
+
+    Stream& operator<<(s64 value) {
+        return *this << static_cast<u64>(value);
+    }
+
+    Stream& operator<<(float value) {
+#ifdef __cpp_lib_bit_cast
+        return *this << std::bit_cast<u32>(value);
+#else
+        static_assert(sizeof(float) == sizeof(u32));
+        u32 int_value;
+        std::memcpy(&int_value, &value, sizeof(int_value));
+        return *this << int_value;
+#endif
+    }
+
+    Stream& operator<<(double value) {
+#ifdef __cpp_lib_bit_cast
+        return *this << std::bit_cast<u64>(value);
+#else
+        static_assert(sizeof(double) == sizeof(u64));
+        u64 int_value;
+        std::memcpy(&int_value, &value, sizeof(int_value));
+        return *this << int_value;
+#endif
+    }
+
+    Stream& operator<<(bool value) {
+        return *this << static_cast<u32>(value ? 1 : 0);
+    }
+
+    Stream& operator<<(Id value) {
+        assert(value.value != 0);
+        return *this << value.value;
+    }
+
+    Stream& operator<<(const Literal& literal) {
+        std::visit([this](auto value) { *this << value; }, literal);
+        return *this;
+    }
+
+    Stream& operator<<(std::string_view string) {
+        InsertStringView(words, insert_index, string);
+        return *this;
+    }
+
+    Stream& operator<<(const char* string) {
+        return *this << std::string_view{string};
+    }
+
+    template <typename T>
+    requires std::is_enum_v<T> Stream& operator<<(T value) {
+        static_assert(sizeof(T) == sizeof(u32));
+        return *this << static_cast<u32>(value);
+    }
+
+    template <typename T>
+    Stream& operator<<(std::optional<T> value) {
+        if (value) {
+            *this << *value;
+        }
+        return *this;
+    }
+
+    template <typename T>
+    Stream& operator<<(std::span<const T> values) {
+        for (const auto& value : values) {
+            *this << value;
+        }
+        return *this;
+    }
+
+private:
+    u32* bound = nullptr;
+    std::vector<u32> words;
+    size_t insert_index = 0;
+    size_t op_index = 0;
+};
+
+class Declarations {
+public:
+    explicit Declarations(u32* bound) : stream{bound} {}
+
+    void Reserve(size_t num_words) {
+        return stream.Reserve(num_words);
+    }
+
+    std::span<const u32> Words() const noexcept {
+        return stream.Words();
+    }
+
+    template <typename T>
+    Declarations& operator<<(const T& value) {
+        stream << value;
+        return *this;
+    }
+
+    // Declarations without an id don't exist
+    Declarations& operator<<(spv::Op) = delete;
+
+    Declarations& operator<<(OpId op) {
+        id_index = op.result_type.value != 0 ? 2 : 1;
+        stream << op;
+        return *this;
+    }
+
+    Id operator<<(EndOp) {
+        const auto begin = stream.words.data();
+        std::vector<u32> declarations(begin + stream.op_index, begin + stream.insert_index);
+
+        // Normalize result id for lookups
+        const u32 id = std::exchange(declarations[id_index], 0);
+
+        const auto [entry, inserted] = existing_declarations.emplace(declarations, id);
+        if (inserted) {
+            return stream << EndOp{};
+        }
+        // If the declaration already exists, undo the operation
+        stream.insert_index = stream.op_index;
+        --*stream.bound;
+
+        return Id{entry->second};
+    }
+
+private:
+    struct HashVector {
+        size_t operator()(const std::vector<u32>& vector) const noexcept {
+            size_t hash = std::hash<size_t>{}(vector.size());
+            for (const u32 value : vector) {
+                hash ^= std::hash<u32>{}(value);
+            }
+            return hash;
+        }
+    };
+
+    Stream stream;
+    std::unordered_map<std::vector<u32>, u32, HashVector> existing_declarations;
+    size_t id_index = 0;
+};
+
+} // namespace Sirit