#=============================================================================
# Copyright 2009 Kitware, Inc.
# Copyright 2006 Tristan Carel
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#=============================================================================

FIND_PROGRAM(FLEX_EXECUTABLE flex DOC "path to the flex executable")
MARK_AS_ADVANCED(FLEX_EXECUTABLE)

FIND_LIBRARY(FL_LIBRARY NAMES fl
  DOC "Path to the fl library")

FIND_PATH(FLEX_INCLUDE_DIR FlexLexer.h
  DOC "Path to the flex headers")

MARK_AS_ADVANCED(FL_LIBRARY FLEX_INCLUDE_DIR)

SET(FLEX_INCLUDE_DIRS ${FLEX_INCLUDE_DIR})
SET(FLEX_LIBRARIES ${FL_LIBRARY})

IF(FLEX_EXECUTABLE)

  EXECUTE_PROCESS(COMMAND ${FLEX_EXECUTABLE} --version
    OUTPUT_VARIABLE FLEX_version_output
    ERROR_VARIABLE FLEX_version_error
    RESULT_VARIABLE FLEX_version_result
    OUTPUT_STRIP_TRAILING_WHITESPACE)
  IF(NOT ${FLEX_version_result} EQUAL 0)
    IF(FLEX_FIND_REQUIRED)
      MESSAGE(SEND_ERROR "Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}")
    ELSE()
      MESSAGE("Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}\nFLEX_VERSION will not be available")
    ENDIF()
  ELSE()
    STRING(REGEX REPLACE "^flex (.*)$" "\\1"
      FLEX_VERSION "${FLEX_version_output}")
  ENDIF()

  #============================================================
  # FLEX_TARGET (public macro)
  #============================================================
  #
  MACRO(FLEX_TARGET Name Input Output)
    SET(FLEX_TARGET_usage "FLEX_TARGET(<Name> <Input> <Output> [COMPILE_FLAGS <string>]")
    IF(${ARGC} GREATER 3)
      IF(${ARGC} EQUAL 5)
        IF("${ARGV3}" STREQUAL "COMPILE_FLAGS")
          SET(FLEX_EXECUTABLE_opts  "${ARGV4}")
          SEPARATE_ARGUMENTS(FLEX_EXECUTABLE_opts)
        ELSE()
          MESSAGE(SEND_ERROR ${FLEX_TARGET_usage})
        ENDIF()
      ELSE()
        MESSAGE(SEND_ERROR ${FLEX_TARGET_usage})
      ENDIF()
    ENDIF()

    STRING(REGEX REPLACE "^(.*)(\\.[^.]*)$" "\\2" _fileext "${Output}")
    STRING(REPLACE "c" "h" _fileext ${_fileext})
    STRING(REGEX REPLACE "^(.*)(\\.[^.]*)$" "\\1${_fileext}"
       OutputHeader "${Output}")

    ADD_CUSTOM_COMMAND(OUTPUT ${Output} ${OutputHeader}
      COMMAND ${FLEX_EXECUTABLE}
      ARGS ${FLEX_EXECUTABLE_opts} -o${Output} --header-file=${OutputHeader} ${Input}
      DEPENDS ${Input}
      COMMENT "[FLEX][${Name}] Building scanner with flex ${FLEX_VERSION}"
      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})

    SET(FLEX_${Name}_DEFINED TRUE)
    SET(FLEX_${Name}_OUTPUTS ${Output} ${OutputHeader})
    SET(FLEX_${Name}_OUTPUT_HEADER ${OutputHeader})
    SET(FLEX_${Name}_INPUT ${Input})
    SET(FLEX_${Name}_COMPILE_FLAGS ${FLEX_EXECUTABLE_opts})
  ENDMACRO(FLEX_TARGET)
  #============================================================


ENDIF(FLEX_EXECUTABLE)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(FLEX REQUIRED_VARS FLEX_EXECUTABLE
                                       VERSION_VAR FLEX_VERSION)

# FindFLEX.cmake ends here