// Copyright (c) 2015-2016 The Khronos Group Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef SOURCE_TEXT_HANDLER_H_

#define SOURCE_TEXT_HANDLER_H_

#include <iomanip>

#include <set>

#include <sstream>

#include <string>

#include <type_traits>

#include <unordered_map>

#include <utility>

#include "source/diagnostic.h"

#include "source/instruction.h"

#include "source/text.h"

#include "spirv-tools/libspirv.h"

namespace spvtools {

// Structures

// This is a lattice for tracking types.

enum class IdTypeClass {

  kBottom = 0,  // We have no information yet.

  kScalarIntegerType,

  kScalarFloatType,

  kOtherType

};

// Contains ID type information that needs to be tracked across all Ids.

// Bitwidth is only valid when type_class is kScalarIntegerType or

// kScalarFloatType.

struct IdType {

  uint32_t bitwidth;  // Safe to assume that we will not have > 2^32 bits.

  bool isSigned;      // This is only significant if type_class is integral.

  IdTypeClass type_class;

  spv_fp_encoding_t encoding;

};

// Default equality operator for IdType. Tests if all members are the same.

inline bool operator==(const IdType& first, const IdType& second) {

  return (first.bitwidth == second.bitwidth) &&

         (first.isSigned == second.isSigned) &&

         (first.type_class == second.type_class);

}

// Tests whether any member of the IdTypes do not match.

inline bool operator!=(const IdType& first, const IdType& second) {

  return !(first == second);

}

// A value representing an unknown type.

extern const IdType kUnknownType;

// Returns true if the type is a scalar integer type.

inline bool isScalarIntegral(const IdType& type) {

  return type.type_class == IdTypeClass::kScalarIntegerType;

}

// Returns true if the type is a scalar floating point type.

inline bool isScalarFloating(const IdType& type) {

  return type.type_class == IdTypeClass::kScalarFloatType;

}

// Returns the number of bits in the type.

// This is only valid for bottom, scalar integer, and scalar floating

// classes.  For bottom, assume 32 bits.

inline int assumedBitWidth(const IdType& type) {

  switch (type.type_class) {

    case IdTypeClass::kBottom:

      return 32;

    case IdTypeClass::kScalarIntegerType:

    case IdTypeClass::kScalarFloatType:

      return type.bitwidth;

    default:

      break;

  }

  // We don't care about this case.

  return 0;

}

// A templated class with a static member function Clamp, where Clamp

// sets a referenced value of type T to 0 if T is an unsigned

// integer type, and returns true if it modified the referenced

// value.

template <typename T, typename = void>

class ClampToZeroIfUnsignedType {

 public:

  // The default specialization does not clamp the value.

  static bool Clamp(T*) { return false; }

};

// The specialization of ClampToZeroIfUnsignedType for unsigned integer

// types.

template <typename T>

class ClampToZeroIfUnsignedType<

    T, typename std::enable_if<std::is_unsigned<T>::value>::type> {

 public:

  static bool Clamp(T* value_pointer) {

    if (*value_pointer) {

      *value_pointer = 0;

      return true;

    }

    return false;

  }

};

// Encapsulates the data used during the assembly of a SPIR-V module.

class AssemblyContext {

 public:

  AssemblyContext(spv_text text, const MessageConsumer& consumer,

                  std::set<uint32_t>&& ids_to_preserve = std::set<uint32_t>())

      : current_position_({}),

        consumer_(consumer),

        text_(text),

        bound_(1),

        next_id_(1),

        ids_to_preserve_(std::move(ids_to_preserve)) {}

  // Assigns a new integer value to the given text ID, or returns the previously

  // assigned integer value if the ID has been seen before.

  uint32_t spvNamedIdAssignOrGet(const char* textValue);

  // Returns the largest largest numeric ID that has been assigned.

  uint32_t getBound() const;

  // Advances position to point to the next word in the input stream.

  // Returns SPV_SUCCESS on success.

  spv_result_t advance();

  // Sets word to the next word in the input text. Fills next_position with

  // the next location past the end of the word.  Returns an error if the

  // context is invalid or has no more text. Otherwise returns SPV_SUCCESS.

  // Assumes the next part of the input is not whitespace.

  //

  // A word ends at the next comment or whitespace.  However, double-quoted

  // strings remain intact, and a backslash always escapes the next character.

  // The input stream may end before a matching double-quote, or immediately

  // after a backslash. Both such cases still count as success.

  spv_result_t getWord(std::string* word, spv_position next_position);

  // Returns true if the next word in the input is the start of a new Opcode.

  bool startsWithOp();

  // Returns true if the next word in the input is the start of a new

  // instruction.

  bool isStartOfNewInst();

  // Returns a diagnostic object initialized with current position in the input

  // stream, and for the given error code. Any data written to this object will

  // show up in pDiagnsotic on destruction.

  DiagnosticStream diagnostic(spv_result_t error) {

    return DiagnosticStream(current_position_, consumer_, "", error);

  }

  // Returns a diagnostic object with the default assembly error code.

  DiagnosticStream diagnostic() {

    // The default failure for assembly is invalid text.

    return diagnostic(SPV_ERROR_INVALID_TEXT);

  }

  // Returns then next character in the input stream.

  char peek() const;

  // Returns true if there is more text in the input stream.

  bool hasText() const;

  // Seeks the input stream forward by 'size' characters.

  void seekForward(uint32_t size);

  // Sets the current position in the input stream to the given position.

  void setPosition(const spv_position_t& newPosition) {

    current_position_ = newPosition;

  }

  // Returns the current position in the input stream.

  const spv_position_t& position() const { return current_position_; }

  // Appends the given 32-bit value to the given instruction.

  // Returns SPV_SUCCESS if the value could be correctly inserted in the

  // instruction.

  spv_result_t binaryEncodeU32(const uint32_t value, spv_instruction_t* pInst);

  // Appends the given string to the given instruction.

  // Returns SPV_SUCCESS if the value could be correctly inserted in the

  // instruction.

  spv_result_t binaryEncodeString(const char* value, spv_instruction_t* pInst);

  // Appends the given numeric literal to the given instruction.

  // Validates and respects the bitwidth supplied in the IdType argument.

  // If the type is of class kBottom the value will be encoded as a

  // 32-bit integer.

  // Returns SPV_SUCCESS if the value could be correctly added to the

  // instruction.  Returns the given error code on failure, and emits

  // a diagnostic if that error code is not SPV_FAILED_MATCH.

  spv_result_t binaryEncodeNumericLiteral(const char* numeric_literal,

                                          spv_result_t error_code,

                                          const IdType& type,

                                          spv_instruction_t* pInst);

  // Returns the IdType associated with this type-generating value.

  // If the type has not been previously recorded with recordTypeDefinition,

  // kUnknownType  will be returned.

  IdType getTypeOfTypeGeneratingValue(uint32_t value) const;

  // Returns the IdType that represents the return value of this Value

  // generating instruction.

  // If the value has not been recorded with recordTypeIdForValue, or the type

  // could not be determined kUnknownType will be returned.

  IdType getTypeOfValueInstruction(uint32_t value) const;

  // Tracks the type-defining instruction. The result of the tracking can

  // later be queried using getValueType.

  // pInst is expected to be completely filled in by the time this instruction

  // is called.

  // Returns SPV_SUCCESS on success, or SPV_ERROR_INVALID_VALUE on error.

  spv_result_t recordTypeDefinition(const spv_instruction_t* pInst);

  // Tracks the relationship between the value and its type.

  spv_result_t recordTypeIdForValue(uint32_t value, uint32_t type);

  // Records the given Id as being the import of the given extended instruction

  // type.

  spv_result_t recordIdAsExtInstImport(uint32_t id, spv_ext_inst_type_t type);

  // Returns the extended instruction type corresponding to the import with

  // the given Id, if it exists.  Returns SPV_EXT_INST_TYPE_NONE if the

  // id is not the id for an extended instruction type.

  spv_ext_inst_type_t getExtInstTypeForId(uint32_t id) const;

  // Returns a set consisting of each ID generated by spvNamedIdAssignOrGet from

  // a numeric ID text representation. For example, generated from "%12" but not

  // from "%foo".

  std::set<uint32_t> GetNumericIds() const;

 private:

  // Maps ID names to their corresponding numerical ids.

  using spv_named_id_table = std::unordered_map<std::string, uint32_t>;

  // Maps type-defining IDs to their IdType.

  using spv_id_to_type_map = std::unordered_map<uint32_t, IdType>;

  // Maps Ids to the id of their type.

  using spv_id_to_type_id = std::unordered_map<uint32_t, uint32_t>;

  spv_named_id_table named_ids_;

  spv_id_to_type_map types_;

  spv_id_to_type_id value_types_;

  // Maps an extended instruction import Id to the extended instruction type.

  std::unordered_map<uint32_t, spv_ext_inst_type_t> import_id_to_ext_inst_type_;

  spv_position_t current_position_;

  MessageConsumer consumer_;

  spv_text text_;

  uint32_t bound_;

  uint32_t next_id_;

  std::set<uint32_t> ids_to_preserve_;

};

}  // namespace spvtools

#endif  // SOURCE_TEXT_HANDLER_H_