// 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"

namespace tint {

SymbolTable::SymbolTable(tint::GenerationID generation_id) : generation_id_(generation_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_.Find(name);
    if (it) {
        return *it;
    }
    return RegisterInternal(name);
}

Symbol SymbolTable::RegisterInternal(std::string_view name) {
    char* name_mem = Bitcast<char*>(name_allocator_.Allocate(name.length() + 1));
    if (name_mem == nullptr) {
        TINT_ICE() << "failed to allocate memory for symbol's string";
        return Symbol();
    }

    memcpy(name_mem, name.data(), name.length() + 1);
    std::string_view nv(name_mem, name.length());

    Symbol sym(next_symbol_, generation_id_, nv);
    ++next_symbol_;
    name_to_symbol_.Add(sym.NameView(), sym);

    return sym;
}

Symbol SymbolTable::Get(std::string_view name) const {
    auto it = name_to_symbol_.Find(name);
    return it ? *it : 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_.Find(prefix);
    if (!it) {
        return RegisterInternal(prefix);
    }

    size_t i = 0;
    auto last_prefix = last_prefix_to_index_.Find(prefix);
    if (last_prefix) {
        i = *last_prefix;
    }

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

    auto sym = RegisterInternal(name);
    if (last_prefix) {
        *last_prefix = i;
    } else {
        last_prefix_to_index_.Add(prefix, i);
    }
    return sym;
}

}  // namespace tint
