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      1 #
      2 # Copyright (C) 2017 The Android Open Source Project
      3 #
      4 # Licensed under the Apache License, Version 2.0 (the "License");
      5 # you may not use this file except in compliance with the License.
      6 # You may obtain a copy of the License at
      7 #
      8 #      http://www.apache.org/licenses/LICENSE-2.0
      9 #
     10 # Unless required by applicable law or agreed to in writing, software
     11 # distributed under the License is distributed on an "AS IS" BASIS,
     12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 # See the License for the specific language governing permissions and
     14 # limitations under the License.
     15 #
     16 
     17 ###########################################################
     18 # Basic math functions for positive integers <= 100
     19 #
     20 # (SDK versions for example)
     21 ###########################################################
     22 __MATH_NUMBERS :=  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 \
     23                   21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 \
     24                   41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 \
     25                   61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 \
     26                   81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
     27 
     28 # Returns true if $(1) is a positive integer <= 100, otherwise returns nothing.
     29 define math_is_number
     30 $(strip \
     31   $(if $(1),,$(error Argument missing)) \
     32   $(if $(word 2,$(1)),$(error Multiple words in a single argument: $(1))) \
     33   $(if $(filter $(1),$(__MATH_NUMBERS)),true))
     34 endef
     35 
     36 #$(warning true == $(call math_is_number,2))
     37 #$(warning == $(call math_is_number,foo))
     38 #$(call math_is_number,1 2)
     39 #$(call math_is_number,no 2)
     40 
     41 define _math_check_valid
     42 $(if $(call math_is_number,$(1)),,$(error Only positive integers <= 100 are supported (not $(1))))
     43 endef
     44 
     45 #$(call _math_check_valid,0)
     46 #$(call _math_check_valid,1)
     47 #$(call _math_check_valid,100)
     48 #$(call _math_check_valid,101)
     49 #$(call _math_check_valid,)
     50 #$(call _math_check_valid,1 2)
     51 
     52 # Returns the greater of $1 or $2.
     53 # If $1 or $2 is not a positive integer <= 100, then an error is generated.
     54 define math_max
     55 $(strip $(call _math_check_valid,$(1)) $(call _math_check_valid,$(2)) \
     56   $(lastword $(filter $(1) $(2),$(__MATH_NUMBERS))))
     57 endef
     58 
     59 #$(call math_max)
     60 #$(call math_max,1)
     61 #$(call math_max,1 2,3)
     62 #$(warning 1 == $(call math_max,1,1))
     63 #$(warning 42 == $(call math_max,5,42))
     64 #$(warning 42 == $(call math_max,42,5))
     65 
     66 define math_gt_or_eq
     67 $(if $(filter $(1),$(call math_max,$(1),$(2))),true)
     68 endef
     69 
     70 #$(warning $(call math_gt_or_eq, 2, 1))
     71 #$(warning $(call math_gt_or_eq, 1, 1))
     72 #$(warning $(if $(call math_gt_or_eq, 1, 2),false,true))
     73 
     74 # $1 is the variable name to increment
     75 define inc_and_print
     76 $(strip $(eval $(1) := $($(1)) .)$(words $($(1))))
     77 endef
     78