zeek/tools/binpac/src/pac_case.cc

// See the file "COPYING" in the main distribution directory for copyright.

#include "pac_case.h"

#include <stdint.h>
#include <limits>

#include "pac_btype.h"
#include "pac_exception.h"
#include "pac_expr.h"
#include "pac_exttype.h"
#include "pac_id.h"
#include "pac_output.h"
#include "pac_typedecl.h"
#include "pac_utils.h"

CaseType::CaseType(Expr* index_expr, CaseFieldList* cases) : Type(CASE), index_expr_(index_expr), cases_(cases) {
    index_var_ = nullptr;
    foreach (i, CaseFieldList, cases_)
        AddField(*i);
}

CaseType::~CaseType() {
    delete index_var_;
    delete index_expr_;
    delete cases_;
}

void CaseType::AddCaseField(CaseField* f) {
    // All fields must be added before Prepare()
    ASSERT(! env());

    AddField(f);
    cases_->push_back(f);
}

bool CaseType::DefineValueVar() const { return false; }

string CaseType::DataTypeStr() const {
    ASSERT(type_decl());
    return strfmt("%s*", type_decl()->class_name().c_str());
}

Type* CaseType::ValueType() const {
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        return c->type();
    }
    ASSERT(0);
    return nullptr;
}

string CaseType::DefaultValue() const { return ValueType()->DefaultValue(); }

void CaseType::Prepare(Env* env, int flags) {
    ASSERT(flags & TO_BE_PARSED);

    index_var_ = new ID(strfmt("%s_case_index", value_var()->Name()));
    // Unable to get the type for index_var_ at this moment, but we'll
    // generate the right type based on index_expr_ later.
    env->AddID(index_var_, MEMBER_VAR, nullptr);

    // Sort the cases_ to put the default case at the end of the list
    CaseFieldList::iterator default_case_it = cases_->end(); // to avoid warning
    CaseField* default_case = nullptr;

    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        if ( ! c->index() ) {
            if ( default_case )
                throw Exception(c, "duplicate default case");
            default_case_it = i;
            default_case = c;
        }
    }
    if ( default_case ) {
        cases_->erase(default_case_it);
        cases_->push_back(default_case);
    }

    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        c->set_index_var(index_var_);
        c->set_case_type(this);
    }

    Type::Prepare(env, flags);
}

void CaseType::GenPrivDecls(Output* out_h, Env* env) {
    Type* t = index_expr_->DataType(env);

    if ( t->tot() != Type::BUILTIN )
        // It's a Type::EXTERN with a C++ type of "int", "bool", or "enum",
        // any of which will convert consistently using an int as storage type.
        t = extern_type_int;

    out_h->println("%s %s;", t->DataTypeStr().c_str(), env->LValue(index_var_));
    Type::GenPrivDecls(out_h, env);
}

void CaseType::GenPubDecls(Output* out_h, Env* env) {
    Type* t = index_expr_->DataType(env);

    if ( t->tot() != Type::BUILTIN )
        t = extern_type_int;

    out_h->println("%s %s const	{ return %s; }", t->DataTypeStr().c_str(), env->RValue(index_var_),
                   env->LValue(index_var_));
    Type::GenPubDecls(out_h, env);
}

void CaseType::GenInitCode(Output* out_cc, Env* env) {
    out_cc->println("%s = -1;", env->LValue(index_var_));
    Type::GenInitCode(out_cc, env);
}

void CaseType::GenCleanUpCode(Output* out_cc, Env* env) {
    Type::GenCleanUpCode(out_cc, env);

    env->set_in_branch(true);
    out_cc->println("// NOLINTBEGIN(bugprone-branch-clone)");
    out_cc->println("switch ( %s ) {", env->RValue(index_var_));
    out_cc->inc_indent();
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        c->GenCleanUpCode(out_cc, env);
    }
    out_cc->dec_indent();
    out_cc->println("}");
    out_cc->println("// NOLINTEND(bugprone-branch-clone)");
    env->set_in_branch(false);
}

void CaseType::DoGenParseCode(Output* out_cc, Env* env, const DataPtr& data, int flags) {
    if ( StaticSize(env) >= 0 )
        GenBoundaryCheck(out_cc, env, data);

    bool compute_size_var = false;

    if ( ! incremental_input() )
        compute_size_var = AddSizeVar(out_cc, env);

    out_cc->println("%s = %s;", env->LValue(index_var_), index_expr_->EvalExpr(out_cc, env));
    env->SetEvaluated(index_var_);

    env->set_in_branch(true);
    out_cc->println("// NOLINTBEGIN(bugprone-branch-clone)");
    out_cc->println("switch ( %s ) {", env->RValue(index_var_));
    out_cc->inc_indent();
    bool has_default_case = false;
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        c->GenParseCode(out_cc, env, data, compute_size_var ? size_var() : nullptr);
        if ( c->IsDefaultCase() )
            has_default_case = true;
    }

    if ( ! has_default_case ) {
        out_cc->println("default:");
        out_cc->inc_indent();
        out_cc->println("throw binpac::ExceptionInvalidCaseIndex(\"%s\", (int64)%s);", decl_id()->Name(),
                        env->RValue(index_var_));
        out_cc->println("break;");
        out_cc->dec_indent();
    }
    out_cc->dec_indent();
    out_cc->println("}");
    out_cc->println("// NOLINTEND(bugprone-branch-clone)");
    env->set_in_branch(false);

    if ( compute_size_var )
        env->SetEvaluated(size_var());
}

void CaseType::GenDynamicSize(Output* out_cc, Env* env, const DataPtr& data) { GenParseCode(out_cc, env, data, 0); }

int CaseType::StaticSize(Env* env) const {
    int static_w = -1;
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        int w = c->StaticSize(env);
        if ( w < 0 || (static_w >= 0 && w != static_w) )
            return -1;
        static_w = w;
    }
    return static_w;
}

void CaseType::SetBoundaryChecked() {
    Type::SetBoundaryChecked();
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        c->SetBoundaryChecked();
    }
}

void CaseType::DoMarkIncrementalInput() {
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        c->type()->MarkIncrementalInput();
    }
}

bool CaseType::ByteOrderSensitive() const {
    foreach (i, CaseFieldList, cases_) {
        CaseField* c = *i;
        if ( c->RequiresByteOrder() )
            return true;
    }
    return false;
}

CaseField::CaseField(ExprList* index, ID* id, Type* type)
    : Field(CASE_FIELD, TYPE_TO_BE_PARSED | CLASS_MEMBER | PUBLIC_READABLE, id, type), index_(index) {
    ASSERT(type_);
    type_->set_value_var(id, MEMBER_VAR);
    case_type_ = nullptr;
    index_var_ = nullptr;
}

CaseField::~CaseField() { delete_list(ExprList, index_); }

void GenCaseStr(ExprList* index_list, Output* out_cc, Env* env, Type* switch_type) {
    if ( index_list ) {
        foreach (i, ExprList, index_list) {
            Expr* index_expr = *i;

            Type* case_type = index_expr->DataType(env);

            if ( case_type->tot() == Type::BUILTIN && case_type->StaticSize(env) > 4 )
                throw ExceptionInvalidCaseSizeExpr(index_expr);

            int index_const;

            if ( ! index_expr->ConstFold(env, &index_const) )
                throw ExceptionNonConstExpr(index_expr);

            // External C++ types like "int", "bool", "enum"
            // all use "int" type internally by default.
            int case_type_width = 4;
            int switch_type_width = 4;

            if ( switch_type->tot() == Type::BUILTIN )
                switch_type_width = switch_type->StaticSize(env);

            if ( case_type->tot() == Type::BUILTIN )
                case_type_width = case_type->StaticSize(env);

            if ( case_type_width > switch_type_width ) {
                BuiltInType* st = (BuiltInType*)switch_type;

                if ( switch_type_width == 1 ) {
                    if ( st->bit_type() == BuiltInType::INT8 ) {
                        if ( index_const < std::numeric_limits<int8_t>::min() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                        if ( index_const > std::numeric_limits<int8_t>::max() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                    }
                    else {
                        if ( index_const < std::numeric_limits<uint8_t>::min() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                        if ( index_const > std::numeric_limits<uint8_t>::max() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                    }
                }
                else if ( switch_type_width == 2 ) {
                    if ( st->bit_type() == BuiltInType::INT16 ) {
                        if ( index_const < std::numeric_limits<int16_t>::min() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                        if ( index_const > std::numeric_limits<int16_t>::max() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                    }
                    else {
                        if ( index_const < std::numeric_limits<uint16_t>::min() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                        if ( index_const > std::numeric_limits<uint16_t>::max() )
                            throw ExceptionInvalidCaseLimitExpr(index_expr);
                    }
                }
                else {
                    assert(0);
                }
            }

            // We're always using "int" for storage, so ok to just
            // cast into the type used by the switch statement since
            // some unsafe stuff is already checked above.
            if ( ! switch_type->IsBooleanType() )
                out_cc->println("case ((%s)%d):", switch_type->DataTypeStr().c_str(), index_const);
            else
                out_cc->println("case %s:", index_const == 0 ? "false" : "true");
        }
    }
    else {
        out_cc->println("default:");
    }
}

void CaseField::Prepare(Env* env) {
    ASSERT(index_var_);
    Field::Prepare(env);
}

void CaseField::GenPubDecls(Output* out_h, Env* env) {
    if ( ! ((flags_ & PUBLIC_READABLE) && (flags_ & CLASS_MEMBER)) )
        return;

    // Skip type "empty"
    if ( type_->DataTypeStr().empty() )
        return;

    out_h->println("%s %s const {", type_->DataTypeConstRefStr().c_str(), env->RValue(id_));
    out_h->inc_indent();

    if ( ! index_ )
        out_h->println("return %s;", lvalue());
    else {
        out_h->println("// NOLINTBEGIN(bugprone-branch-clone)");
        out_h->println("switch ( %s ) {", env->RValue(index_var_));
        out_h->inc_indent();
        GenCaseStr(index_, out_h, env, case_type()->IndexExpr()->DataType(env));
        out_h->inc_indent();
        out_h->println("break;  // OK");
        out_h->dec_indent();

        out_h->println("default:");
        out_h->inc_indent();
        out_h->println("throw binpac::ExceptionInvalidCase(\"%s\", (int64)%s, \"%s\");", id_->LocName(),
                       env->RValue(index_var_), OrigExprList(index_).c_str());
        out_h->println("break;");
        out_h->dec_indent();

        out_h->dec_indent();
        out_h->println("}");
        out_h->println("// NOLINTEND(bugprone-branch-clone)");

        out_h->println("return %s;", lvalue());
    }

    out_h->dec_indent();
    out_h->println("}");
}

void CaseField::GenInitCode(Output* out_cc, Env* env) {
    // GenCaseStr(index_, out_cc, env);
    // out_cc->inc_indent();
    // out_cc->println("{");
    // out_cc->println("// Initialize \"%s\"", id_->Name());
    type_->GenInitCode(out_cc, env);
    // out_cc->println("}");
    // out_cc->println("break;");
    // out_cc->dec_indent();
}

void CaseField::GenCleanUpCode(Output* out_cc, Env* env) {
    GenCaseStr(index_, out_cc, env, case_type()->IndexExpr()->DataType(env));
    out_cc->inc_indent();
    out_cc->println("// Clean up \"%s\"", id_->Name());
    if ( ! anonymous_field() ) {
        out_cc->println("{");
        out_cc->inc_indent();
        type_->GenCleanUpCode(out_cc, env);
        out_cc->dec_indent();
        out_cc->println("}");
    }
    else
        out_cc->println("{}");

    out_cc->println("break;");
    out_cc->dec_indent();
}

void CaseField::GenParseCode(Output* out_cc, Env* env, const DataPtr& data, const ID* size_var) {
    GenCaseStr(index_, out_cc, env, case_type()->IndexExpr()->DataType(env));
    out_cc->inc_indent();
    out_cc->println("// Parse \"%s\"", id_->Name());
    out_cc->println("{");
    out_cc->inc_indent();

    {
        Env case_env(env, this);

        type_->GenPreParsing(out_cc, &case_env);
        type_->GenParseCode(out_cc, &case_env, data, 0);
        if ( size_var ) {
            out_cc->println("%s = %s;", case_env.LValue(size_var), type_->DataSize(out_cc, &case_env, data).c_str());
        }
        if ( type_->incremental_input() ) {
            ASSERT(case_type()->parsing_complete_var());
            out_cc->println("%s = %s;", case_env.LValue(case_type()->parsing_complete_var()),
                            case_env.RValue(type_->parsing_complete_var()));
        }
    }

    out_cc->dec_indent();
    out_cc->println("}");
    out_cc->println("break;");
    out_cc->dec_indent();
}

bool CaseField::DoTraverse(DataDepVisitor* visitor) { return Field::DoTraverse(visitor) && type()->Traverse(visitor); }

bool CaseField::RequiresAnalyzerContext() const {
    return Field::RequiresAnalyzerContext() || type()->RequiresAnalyzerContext();
}