DUtils

commit 70bd27857accf796639ab010885620e6bbd63163
Author: Dominik Schmidt <das1993@hotmail.com>
Date:   Mon, 16 Jul 2018 16:05:55 +0000

Initial commit

Add the makefile, bytehist which counts how many timesa certain byte
value occurs, and execpipe, which pipes together multiple commands

Diffstat:
Makefile
 | 
25
+++++++++++++++++++++++++
bytehist.c
 | 
35
+++++++++++++++++++++++++++++++++++
execpipe.c
 | 
46
++++++++++++++++++++++++++++++++++++++++++++++

3 files changed, 106 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -0,0 +1,25 @@
+CC ?= cc
+CFLAGS ?= -g
+DESTDIR ?= ~/.local
+BINDIR ?= $(DESTDIR)/bin
+MANDIR ?= $(DESTDIR)/share/man/
+
+PROGS=bytehist execpipe
+
+all: $(PROGS)
+
+%:%.c
+	$(CC) $(CFLAGS) $^ -o $@
+
+$(BINDIR)/%: %
+	install -m 0755 $< $@
+
+$(MANDIR)/man1/%: %
+	install -m 0755 $< $@
+
+.PHONY:install clean
+
+install: $(addprefix $(INSTALLDIR)/,$(PROGS))
+
+clean:
+	rm -f $(PROGS)
diff --git a/bytehist.c b/bytehist.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <string.h>
+
+int main(int argc, char **argv){
+	unsigned char buf[4092];
+	size_t hist[256];
+	size_t ret=0;
+	size_t i;
+	size_t cnt=0;
+	int relative=1;
+	if(argc>1){
+		if(strcmp("-r", argv[1]) == 0){
+			relative=0;
+		}
+	}
+	for(i=0; i<255; i++){
+		hist[i]=0;
+	}
+	while((ret=read(STDIN_FILENO, buf, sizeof(buf)))>0){
+		for(i=0; i<ret; i++){
+			hist[(size_t)(buf[i])]++;
+		}
+		cnt+=ret;
+	}
+	for(i=0; i<256; i++){
+		if(relative){
+			printf("%lu\t%lu\n", i, hist[i]);
+		}
+		else{
+			printf("%lu\t%e\n", i, (double)hist[i]/cnt);
+		}
+	}
+}
diff --git a/execpipe.c b/execpipe.c
@@ -0,0 +1,46 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <stdlib.h>
+
+int process(int argc, char **argv);
+
+void do_shell(char *cmd){
+	execl("/bin/sh", "sh", "-c", cmd, (char *) 0);
+}
+
+void split(int argc, char **argv){
+	int pipefd[2];
+	if(pipe(pipefd)==-1){
+		perror("Pipeline failed");
+		exit(EXIT_FAILURE);
+	}
+	pid_t pid=fork();
+	if(pid==-1){
+		perror("Forking failed");
+		exit(EXIT_FAILURE);
+	}
+	else if(pid==0){
+		dup2(pipefd[0],STDIN_FILENO);
+		close(pipefd[1]);
+		process(argc-1,argv+1);
+	}
+	else{
+		dup2(pipefd[1],STDOUT_FILENO);
+		close(pipefd[0]);
+		do_shell(argv[0]);
+	}
+}
+
+int process(int argc, char **argv){
+	if(argc==1){
+		do_shell(argv[0]);
+	}
+	else if(argc>1){
+		split(argc,argv);
+	}
+}
+
+int main(int argc, char **argv){
+	process(argc-1,argv+1);
+}