################################################################################
  #
  # This file contains various utility functions used by the package
  # infrastructure, or by the packages themselves.
  #
  ################################################################################
  
  # Case conversion macros. This is inspired by the 'up' macro from gmsl
  # (http://gmsl.sf.net). It is optimised very heavily because these macros
  # are used a lot. It is about 5 times faster than forking a shell and tr.
  #
  # The caseconvert-helper creates a definition of the case conversion macro.
  # After expansion by the outer $(eval ), the UPPERCASE macro is defined as:
  # $(strip $(eval __tmp := $(1))  $(eval __tmp := $(subst a,A,$(__tmp))) ... )
  # In other words, every letter is substituted one by one.
  #
  # The caseconvert-helper allows us to create this definition out of the
  # [FROM] and [TO] lists, so we don't need to write down every substition
  # manually. The uses of $ and $$ quoting are chosen in order to do as
  # much expansion as possible up-front.
  #
  # Note that it would be possible to conceive a slightly more optimal
  # implementation that avoids the use of __tmp, but that would be even
  # more unreadable and is not worth the effort.
  
  [FROM] := a b c d e f g h i j k l m n o p q r s t u v w x y z - .
  [TO]   := A B C D E F G H I J K L M N O P Q R S T U V W X Y Z _ _
  
  define caseconvert-helper
  $(1) = $$(strip \
  	$$(eval __tmp := $$(1))\
  	$(foreach c, $(2),\
  		$$(eval __tmp := $$(subst $(word 1,$(subst :, ,$c)),$(word 2,$(subst :, ,$c)),$$(__tmp))))\
  	$$(__tmp))
  endef
  
  $(eval $(call caseconvert-helper,UPPERCASE,$(join $(addsuffix :,$([FROM])),$([TO]))))
  $(eval $(call caseconvert-helper,LOWERCASE,$(join $(addsuffix :,$([TO])),$([FROM]))))
  
  # Sanitize macro cleans up generic strings so it can be used as a filename
  # and in rules. Particularly useful for VCS version strings, that can contain
  # slashes, colons (OK in filenames but not in rules), and spaces.
  sanitize = $(subst $(space),_,$(subst :,_,$(subst /,_,$(strip $(1)))))
  
  #
  # Manipulation of .config files based on the Kconfig
  # infrastructure. Used by the BusyBox package, the Linux kernel
  # package, and more.
  #
  
  define KCONFIG_ENABLE_OPT # (option, file)
  	$(SED) "/\\<$(1)\\>/d" $(2)
  	echo '$(1)=y' >> $(2)
  endef
  
  define KCONFIG_SET_OPT # (option, value, file)
  	$(SED) "/\\<$(1)\\>/d" $(3)
  	echo '$(1)=$(2)' >> $(3)
  endef
  
  define KCONFIG_DISABLE_OPT # (option, file)
  	$(SED) "/\\<$(1)\\>/d" $(2)
  	echo '# $(1) is not set' >> $(2)
  endef
  
  # Helper functions to determine the name of a package and its
  # directory from its makefile directory, using the $(MAKEFILE_LIST)
  # variable provided by make. This is used by the *-package macros to
  # automagically find where the package is located.
  pkgdir = $(dir $(lastword $(MAKEFILE_LIST)))
  pkgname = $(lastword $(subst /, ,$(pkgdir)))
  
  # Define extractors for different archive suffixes
  INFLATE.bz2  = $(BZCAT)
  INFLATE.gz   = $(ZCAT)
  INFLATE.lzma = $(XZCAT)
  INFLATE.tbz  = $(BZCAT)
  INFLATE.tbz2 = $(BZCAT)
  INFLATE.tgz  = $(ZCAT)
  INFLATE.xz   = $(XZCAT)
  INFLATE.tar  = cat
  # suitable-extractor(filename): returns extractor based on suffix
  suitable-extractor = $(INFLATE$(suffix $(1)))
  
  # MESSAGE Macro -- display a message in bold type
  MESSAGE = echo "$(TERM_BOLD)>>> $($(PKG)_NAME) $($(PKG)_VERSION) $(call qstrip,$(1))$(TERM_RESET)"
  TERM_BOLD := $(shell tput smso 2>/dev/null)
  TERM_RESET := $(shell tput rmso 2>/dev/null)
  
  # Utility functions for 'find'
  # findfileclauses(filelist) => -name 'X' -o -name 'Y'
  findfileclauses = $(call notfirstword,$(patsubst %,-o -name '%',$(1)))
  # finddirclauses(base, dirlist) => -path 'base/dirX' -o -path 'base/dirY'
  finddirclauses = $(call notfirstword,$(patsubst %,-o -path '$(1)/%',$(2)))
  
  # Miscellaneous utility functions
  # notfirstword(wordlist): returns all but the first word in wordlist
  notfirstword = $(wordlist 2,$(words $(1)),$(1))
  
  # Needed for the foreach loops to loop over the list of hooks, so that
  # each hook call is properly separated by a newline.
  define sep
  
  
  endef
  
  PERCENT = %
  QUOTE = '
  # ' # Meh... syntax-highlighting
  
  # This macro properly escapes a command string, then prints it with printf:
  #
  #   - first, backslash '\' are self-escaped, so that they do not escape
  #     the following char and so that printf properly outputs a backslash;
  #
  #   - next, single quotes are escaped by closing an existing one, adding
  #     an escaped one, and re-openning a new one (see below for the reason);
  #
  #   - then '%' signs are self-escaped so that the printf does not interpret
  #     them as a format specifier, in case the variable contains an actual
  #     printf with a format;
  #
  #   - finally, $(sep) is replaced with the literal '
  ' so that make does
  #     not break on the so-expanded variable, but so that the printf does
  #     correctly output an LF.
  #
  # Note: this must be escaped in this order to avoid over-escaping the
  # previously escaped elements.
  #
  # Once everything has been escaped, it is passed between single quotes
  # (that's why the single-quotes are escaped they way they are, above,
  # and why the dollar sign is not escaped) to printf(1). A trailing
  # newline is apended, too.
  #
  # Note: leading or trailing spaces are *not* stripped.
  #
  define PRINTF
  	printf '$(subst $(sep),
  ,\
  			$(subst $(PERCENT),$(PERCENT)$(PERCENT),\
  				$(subst $(QUOTE),$(QUOTE)\$(QUOTE)$(QUOTE),\
  					$(subst \,\\,$(1)))))
  '
  endef
  
  # check-deprecated-variable -- throw an error on deprecated variables
  # example:
  #   $(eval $(call check-deprecated-variable,FOO_MAKE_OPT,FOO_MAKE_OPTS))
  define check-deprecated-variable # (deprecated var, new var)
  ifneq ($$(origin $(1)),undefined)
  $$(error Package error: use $(2) instead of $(1). Please fix your .mk file)
  endif
  endef
  
  #
  # legal-info helper functions
  #
  LEGAL_INFO_SEPARATOR = "::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::"
  
  define legal-warning # text
  	echo "WARNING: $(1)" >>$(LEGAL_WARNINGS)
  endef
  
  define legal-warning-pkg # pkg, text
  	echo "WARNING: $(1): $(2)" >>$(LEGAL_WARNINGS)
  endef
  
  define legal-warning-nosource # pkg, {local|override}
  	$(call legal-warning-pkg,$(1),sources not saved ($(2) packages not handled))
  endef
  
  define legal-manifest # pkg, version, license, license-files, source, url, {HOST|TARGET}
  	echo '"$(1)","$(2)","$(3)","$(4)","$(5)","$(6)"' >>$(LEGAL_MANIFEST_CSV_$(7))
  endef
  
  define legal-license-header # pkg, license-file, {HOST|TARGET}
  	printf "$(LEGAL_INFO_SEPARATOR)
  \t$(1):\
  		$(2)
  $(LEGAL_INFO_SEPARATOR)
  
  
  " >>$(LEGAL_LICENSES_TXT_$(3))
  endef
  
  define legal-license-nofiles # pkg, {HOST|TARGET}
  	$(call legal-license-header,$(1),unknown license file(s),$(2))
  endef
  
  define legal-license-file # pkg, filename, file-fullpath, {HOST|TARGET}
  	$(call legal-license-header,$(1),$(2) file,$(4)) && \
  	cat $(3) >>$(LEGAL_LICENSES_TXT_$(4)) && \
  	echo >>$(LEGAL_LICENSES_TXT_$(4)) && \
  	mkdir -p $(LICENSE_FILES_DIR_$(4))/$(1)/$(dir $(2)) && \
  	cp $(3) $(LICENSE_FILES_DIR_$(4))/$(1)/$(2)
  endef