// Copyright 2020 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this
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//    this list of conditions and the following disclaimer in the documentation
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#include "src/tint/utils/symbol/symbol_table.h"

#include "src/tint/utils/ice/ice.h"
#include "src/utils/compiler.h"

namespace tint {

SymbolTable::SymbolTable() : generation_id_(GenerationID::New()) {}

SymbolTable::SymbolTable(GenerationID gen_id) : generation_id_(gen_id) {}

SymbolTable::SymbolTable(SymbolTable&&) = default;

SymbolTable::~SymbolTable() = default;

SymbolTable& SymbolTable::operator=(SymbolTable&&) = default;

Symbol SymbolTable::Register(std::string_view name) {
    TINT_ASSERT(!name.empty());

    auto& it = name_to_symbol_.GetOrAddZeroEntry(name);
    if (it.value) {
        return Symbol{it.value, generation_id_, it.key};
    }

    auto view = Allocate(name);
    it.key = view;
    it.value = next_symbol_++;
    return Symbol{it.value, generation_id_, view};
}

Symbol SymbolTable::Get(std::string_view name) const {
    if (auto* entry = name_to_symbol_.GetEntry(name)) {
        return Symbol{entry->value, generation_id_, entry->key};
    }
    return Symbol{};
}

Symbol SymbolTable::New(std::string_view prefix_view /* = "" */) {
    std::string prefix;
    if (prefix_view.empty()) {
        prefix = "tint_symbol";
    } else {
        prefix = std::string(prefix_view);
    }

    auto& it = name_to_symbol_.GetOrAddZeroEntry(prefix);
    if (it.value == 0) {
        // prefix is a unique name
        auto view = Allocate(prefix);
        it.key = view;
        it.value = next_symbol_++;
        return Symbol{it.value, generation_id_, view};
    }

    size_t& i = last_prefix_to_index_.GetOrAddZero(prefix);
    std::string name;
    do {
        ++i;
        name = prefix + "_" + std::to_string(i);
    } while (name_to_symbol_.Contains(name));

    auto view = Allocate(name);
    auto id = name_to_symbol_.Add(view, next_symbol_++);
    return Symbol{id.value, generation_id_, view};
}

std::string_view SymbolTable::Allocate(std::string_view name) {
    static_assert(sizeof(char) == 1);
    char* name_mem = Bitcast<char*>(name_allocator_.Allocate(name.length() + 1));
    TINT_ASSERT(name_mem != nullptr) << "failed to allocate memory for symbol's string";

    DAWN_UNSAFE_TODO(memcpy(name_mem, name.data(), name.length() + 1));
    return {name_mem, name.length()};
}

}  // namespace tint
