initial commit

.gitignore

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+.build.mak
+build

Makefile

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+######################################################################
+# Makefile
+#
+# This makefile is the one called by user, but it's only a trampoline
+# to create the build directory and call the real Makefile.build
+#
+# make can be invoqued with 'make build=<your_build_directory> ...'
+# all other options and target are passed to the real makefile.
+#
+# As an exception to the rule of not modifying source directory, a
+# .build.mak file is created to cache the configured build directory.
+# Subsequent invocations of make could be done without passing
+# 'build=...' parameter.
+#
+# distclean target is catched to destroy both the .build.mak and
+# the whole build directory.
+#
+######################################################################
+
+# build directory is cached in BUILD_MAK file between make invocations
+BUILD_MAK = .build.mak
+ifneq ($(wildcard $(BUILD_MAK)),)
+include $(BUILD_MAK)
+endif
+
+# default build directory 'build'
+build ?= build
+
+# ($call quiet-command,CMD,MSG)
+# execute CMD and display MSG
+# if verbose mode is enabled (with 'make V=1`) print full CMD instead of MSG
+quiet-command = $(if $(V),$1,$(if $(2),@echo $2 && $1, @$1))
+
+# if the target is distclean, skip allmost rules
+# to doing anything which will be immediately
+# deleted after
+ifeq ($(filter distclean,$(MAKECMDGOALS)),)
+
+# default target (when one invokes 'make' without target)
+# so we have a non-empty target which could be catched by
+# the catch-all target below.
+default-all:
+
+# The catch-all target, which pass build to the main
+# makefile in the build directory.
+# strip-out 'default-all' for targets' list
+%: | $(build)
+	$(call quiet-command, \
+		$(MAKE) -C $(build) $(filter-out default-all,$@) \
+		, "MAKE $(filter-out default-all,$@)")
+
+# Creates the buld directory
+# and populates it with a link to the build makefile
+$(build): | $(BUILD_MAK)
+	$(call quiet-command,\
+		mkdir -p $@; \
+		ln -sf $(CURDIR)/Makefile.build $@/Makefile \
+		, "MKBUILD $@")
+
+# always create BUILD_MAK to cache build configuration
+# but don't update it if not changed
+$(BUILD_MAK): FORCE
+	@echo build=$(build) > $@.tmp
+	@cmp -s $@.tmp $@ || (mv $@.tmp $@ && echo "GEN  $@")
+	@rm -f $@.tmp
+
+else # if distclean
+
+distclean:
+	$(call quiet-command, rm -rf $(build) $(BUILD_MAK), "DISTCLEAN $(build)")
+
+endif # distclean
+
+
+.PHONY: distclean FORCE
+
+#ifndef V
+#.SILENT:
+#endif

Makefile.build

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+######################################################################
+# Some helper functions
+#
+######################################################################
+
+# $(call inspect,LIST)
+# dump list of variables printing their values and their attributes
+inspect = $(foreach v,$(1),$(info $(v) [$(origin $(v)),$(flavor $(v))] = $($(v))))
+
+# $(call undefine_default,LIST)
+# undefine default variables given in LIST)
+undefine_default = $(foreach v,$(1),$(if $(filter default,$(origin $(v))),$(eval undefine $(v)),))
+
+# $(call setdef_ifdef,VAR,DEFVAR)
+# if DEFVAR exists, set default value of VAR to $(DEFVAR)
+setdefault_ifdef = $(if $(filter undefined,$(origin $(2))),,$(eval $(1) ?= $($(2))))
+
+# $(call clean_bool_true,VALUE)
+# $(call clean_bool_false,VALUE)
+# $(call clean_bool,VALUE)
+# clean_bool,clean_bool_true:
+#   if VALUE is identified as true (true, on, yes, enable, 1, ...) returns 1
+# clean_bool,clean_bool_false:
+#   if VALUE is identified as false (false, off, no, disable, 0, ...) returns an empty string
+clean_bool_true = $(if $(filter true TRUE on ON yes YES enable ENABLE,$(1)),1,$(1))
+clean_bool_false = $(if $(filter false FALSE off OFF no NO disable DISABLE 0,$(1)),,$(1))
+clean_bool = $(call clean_bool_false,$(call clean_bool_true,$(1)))
+
+# $(call quote_spaces,STR)
+# return STR, surrounded by double quotes if it contains spaces
+quote_spaces = $(if $(filter 0 1,$(words $1)),$1,"$1")
+
+# $(call pathsearch,EXEC)
+# returns the full path of EXEC if it exists somewhere in $PATH
+# if not found, returns the unmodified EXEC
+pathsearch = $(if $(filter 1,$(words $(1))),$(firstword $(wildcard $(1) $(addsuffix /$(1),$(subst :, ,$(PATH)))) $(1)),$(1))
+
+# $(call prepend_ccache,PREFIX,EXEC)
+# return 'ccache EXEC' if ccache is not already detected in EXEC
+prepend_ccache = $(if $(filter ccache,$(subst /, ,$(1))),$(1),ccache $(1))
+
+# $(call clean_path,PATH)
+# return a sanitized path: remove //, trailing /
+clean_path = $(subst //,/,$(patsubst %/,%,$1))
+
+# ($call quiet-command,CMD,MSG)
+# execute CMD and display MSG
+# if verbose mode is enabled (with 'make V=1`) print full CMD instead of MSG
+quiet-command = $(if $(V),$1,$(if $(2),@echo $2 && $1, @$1))
+
+
+######################################################################
+# Cached configuration support
+#
+# variables listed in CONFIG_VARS are stored in CONFIG_MAK file
+# containing lines `cache_VAR=value`
+# This file is read on subsequent invocation and set default values
+# of these variables.
+#
+# The file is automatically generated but can be hand-edited.
+#
+######################################################################
+
+CONFIG_MAK = config.mak
+CONFIG_VARS = max
+
+CONFIG_STRING = $(foreach var,$(CONFIG_VARS),$(var)=$(call quote_spaces,$($(var))))
+
+# undefine variables which have a default value set by make itself
+# (mainly CC and CXX)
+$(call undefine_default,$(CONFIG_VARS))
+
+# read the cached variables
+-include $(CONFIG_MAK)
+
+# for all undefined variables set their default values from ones
+# stored in included CONFIG_MAK.
+$(foreach var,$(CONFIG_VARS),$(call setdefault_ifdef,$(var),cache_$(var)))
+
+#default (non false) values
+# max ?= 10
+
+# cleanup "False" boolean values, set them to empty value
+$(foreach var,$(CONFIG_VARS),$(eval override $(var):=$(call clean_bool_false,$($(var)))))
+
+# print out user configuration
+# (only once in case the makefile has been reloaded)
+ifndef MAKE_RESTARTS
+$(info CONF $(CONFIG_STRING))
+endif
+
+
+######################################################################
+# Flags generation
+#
+######################################################################
+
+CFLAGS =
+
+ifdef max
+CFLAGS += -DFIBO_MAX=$(max)
+endif
+
+
+######################################################################
+# Source and objects collection
+#
+######################################################################
+
+.SUFFIXES:
+.SUFFIXES: .c .o
+
+ifdef srcdir
+srcdir := $(patsubst %/,%,$(srcdir))
+else
+srcdir := $(patsubst %/,%,$(dir $(realpath $(firstword $(MAKEFILE_LIST)))))
+endif
+
+INCLUDES := src \
+            src/version \
+	    src/fibo
+
+SRCS := src/main.c \
+	src/version/version_tools.c \
+	src/fibo/fibo.c
+
+OBJS += src/version/version.o
+OBJS += $(SRCS:%.c=%.o)
+
+
+VPATH += $(srcdir)
+VPATH += .
+
+CFLAGS += $(addprefix -I$(srcdir)/,$(INCLUDES))
+
+GENERATED += $(OBJS)
+GENERATED += $(DEPDIR)
+GENERATED += src/version/version.c
+GENERATED += fibo
+
+######################################################################
+# Dependencies tracking
+#
+######################################################################
+
+DEPDIR   := .deps
+DEPFLAGS = -MT $@ -MMD -MP -MF $(DEPDIR)/$*.Td #generate dependency file in a temporary file
+
+#Rename the generated temporary dependency file to the real dependency file.
+#We do this in a separate step so that failures during the compilation wont leave a corrupted dependency file
+#in some rare cases dep file can end up beeing newer than object, final touch ensures that object will always
+#be newer.
+POSTCOMPILE = @mv -f $(DEPDIR)/$*.Td $(DEPDIR)/$*.d && touch $@
+
+CFLAGS += $(DEPFLAGS)
+
+
+######################################################################
+# Targets
+#
+######################################################################
+.SECONDEXPANSION:
+
+all:	fibo
+
+fibo:	$(OBJS)
+	$(call quiet-command, $(CC) $^ -o $@, "LINK $@")
+
+%.c: %.c.in FORCE
+	@mkdir -p $(@D)
+	@sed -e 's#@@GIT_SHA1@@#$(shell git describe --all --long --dirty)#' $< > $@.tmp
+	@cmp -s $@.tmp $@ || (echo "GEN  $@"; mv $@.tmp $@)
+	@rm -f $@.tmp
+
+.PRECIOUS: src/version/version.c
+
+%.o: %.c | $(DEPDIR)/$$(@D)/
+	$(call quiet-command, $(CC) $(CFLAGS) $(IFLAGS) -o $@ -c $<, "CC   $@")
+	$(POSTCOMPILE)
+
+
+%/:
+	@mkdir -p $@
+
+# Generate the cached configuration make script
+# - always generated
+# - file is written out only if modified
+$(CONFIG_MAK): FORCE
+	@echo "# automatically generated" > $@.tmp
+	@$(foreach var,$(CONFIG_VARS),echo cache_$(var)=$($(var)) >> $@.tmp;)
+	@cmp -s $@.tmp $@ || (echo "GEN  $@"; mv $@.tmp $@)
+	@rm -f $@.tmp
+
+$(OBJS): $(MAKEFILE_LIST)
+
+inspect:
+	$(call inspect,srcdir)
+	$(call inspect,SRCS)
+	$(call inspect,OBJS)
+	$(call inspect,SHELL)
+
+clean:
+	$(call quiet-command, rm -rf $(GENERATED), "CLEAN")
+
+distclean:
+	$(call quiet-command, rm -rf $(GENERATED) $(CONFIG_MAK) Makefile, "DISTCLEAN")
+
+.PHONY: FORCE clean inspect
+
+# include all potential dependencies files
+-include $(patsubst %,$(DEPDIR)/%.d,$(basename $(SRCS)))
+
+

src/fibo/fibo.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include "fibo.h"
+
+
+static int *fibo;
+static u_int64_t fibo_size;
+
+
+void fibo_init(int size)
+{
+  fibo = calloc(size, sizeof(u_int64_t));
+  if (fibo == NULL) {
+    fprintf(stderr, "ERROR: cannot allocate memory\n");
+    exit(1);
+  }
+  fibo_size = size;
+}
+
+
+void fibo_compute(void)
+{
+  fibo[0] = 1;
+  fibo[1] = 1;
+  for (int i = 2; i < fibo_size; i++)
+    fibo[i] = fibo[i-2] + fibo[i-1];
+}
+
+
+void fibo_print()
+{
+  printf("fibo:");
+  for (int i=0; i<fibo_size; i++)
+    printf(" %lu", fibo[i]);
+  printf("\n");
+}
+

src/fibo/fibo.h

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+
+void fibo_init(int size);
+void fibo_compute(void);
+void fibo_print(void);
+

src/main.c

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+#include "version_tools.h"
+#include "fibo.h"
+
+
+#ifdef FIBO_MAX
+#define MAIN_FIBO_MAX FIBO_MAX
+#else
+#define MAIN_FIBO_MAX 10
+#endif
+
+
+int main(int argc, char *argv[])
+{
+  print_version();
+
+  fibo_init(MAIN_FIBO_MAX);
+  fibo_compute();
+  fibo_print();
+
+  return 0;
+}

src/version/version.c.in

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+
+const char* git_sha1 = "@@GIT_SHA1@@";
+

src/version/version.h

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+
+
+extern const char *git_sha1;
+

src/version/version_tools.c

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+#include <stdio.h>
+#include "version.h"
+
+
+void print_version(void)
+{
+  printf("version: %s\n", git_sha1);
+}

src/version/version_tools.h

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+
+void print_version(void);
+