Added optimization and updated copyright year

The number of calls to malloc and free were reduced by reusing the buffer. This *should* speed up the program with large ammounts of files
Changed the copyright year to 2024

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023 Adam McKenney
+Copyright (c) 2024 Adam McKenney
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

slimcat.1

@@ -17,7 +17,7 @@ slimcat -h
 Displays help.
 .TP
 slimcat -u
-Tells the OS that we dont want a buffer (warning may be a lot slower with a large file).
+Tells the OS that we do not want a buffer (warning may be a lot slower with a large file).
 .TP
 slimcat x \- y
 Output x's contents, then standard input, then y's contents.
@@ -46,7 +46,7 @@ Written by Adam McKenney
 .SH "REPORTING BUGS"
 See the offical repo: <https://github.com/mckenney5/slim-cat>
 .SH COPYRIGHT
-Copyright \(co 2023 Adam McKenney
+Copyright \(co 2024 Adam McKenney
 
 
 Permission is hereby granted, free of charge, to any person obtaining a copy

src/cat.c

@@ -1,56 +1,67 @@
-/* Copyright 2023 (c) Adam McKenney - See LICENSE for details */
+/* Copyright 2024 (c) Adam McKenney - See LICENSE for details */
 /* A way slimmer version of cat without the GNU bloat features that I have never used nor needed */
-#include <stdlib.h> //malloc
-#include <err.h> //err, errx
-#include <sysexits.h> //EX_OK, EX_OSERR, EX_IOERR, EX_NOINPUT
-#include <unistd.h> //read, write, close
-#include <sys/types.h> //stat
-#include <sys/stat.h> //stat
+#include <stdlib.h> 	  //malloc
+#include <err.h> 	  //err, errx
+#include <sysexits.h> 	  //EX_OK, EX_OSERR, EX_IOERR, EX_NOINPUT
+#include <unistd.h> 	  //read, write, close
+#include <sys/types.h> 	  //stat
+#include <sys/stat.h> 	  //stat
 #include <sys/sendfile.h> //sendfile
-#include <fcntl.h> //open, STDIN_FILENO, STDOUT_FILENO
+#include <fcntl.h> 	  //open, STDIN_FILENO, STDOUT_FILENO
 
-#define NAME "cat"   //Program name, can be changed so a user can keep their bloated version of cat
+#define NAME "cat" //Program name, can be changed so a user can keep their bloated version of cat
 #define HELP "Usage: " NAME " [-hu] [file...]\nWe concatenate files(s) to standard output with about 60 lines of code.\n\nWith no file, or when file is -, read standard input.\nExamples:\n  " NAME " -h     Displays the help\n  " NAME " -u     Tells the OS that we dont want a buffer (warning may be a lot slower with a large file).\n  " NAME " x - y  Output x's contents, then standard input, then y's contents.\n  " NAME "        Copy standard input to standard output."
 #define BUFF_SIZE 10000 //a larger buffer trades memory for speed
 #define MAX_SENDFILE_LINUX 2147479552 //max file size for sendfile in Linux
 
-void cat(const int fd, const char no_buf, size_t size){
+void cat(const int fd, const char no_buf, size_t size, const size_t files_pending){
 /* reads from the file descriptor into buf, until zero bytes are read  */
 	//tries sendfile if available (since it is faster, if not, do sys read & write)
 	if(fd == STDIN_FILENO || size > MAX_SENDFILE_LINUX || sendfile(STDOUT_FILENO, fd, 0, size) != size){
+		//if we cannot use sendfile, use the code below
 		size_t r = 0;
 		if(no_buf) size = 1;
-		void *buf = (void*)malloc(size);
+		static void *buf = NULL;
+		static size_t buf_size = 0;
+		if(buf_size < size){
+			buf = realloc(buf, size); //reuse buffer if we can, if buf starts as null then it will malloc automatically
+			buf_size = size;
+		}
 		if(buf == NULL) err(EX_OSERR, "while allocating buf in cat()");
+
 		while((r=read(fd, buf, size)) > 0)
 			if(write(STDOUT_FILENO, buf, r) != r) err(EX_IOERR, "while writing to fd in cat(). %ld bytes were written", r); //if writing stops for some reason
 		if(r == -1) err(EX_IOERR, "while reading fd in cat()."); //if read(2) throws an error
-		free(buf);
+		if(files_pending == 1){
+		 //allows us to reuse the buffer until we are at the last file
+			free(buf);
+			buf_size = 0;
+		}
 	} 
 }
-void get_file(const char* file_name, const char no_buf){
+void get_file(const char* file_name, const char no_buf, const size_t files_pending){
 /* tries to open the user's file, then calls cat() with its file pointer */
-	if(file_name[0] == '-' && file_name[1] == '\0'){ cat(STDIN_FILENO, no_buf, BUFF_SIZE); return;}
+	if(file_name[0] == '-' && file_name[1] == '\0'){ cat(STDIN_FILENO, no_buf, BUFF_SIZE, files_pending); return;}
 	struct stat buffer;
 	int fd = -1, status = stat(file_name, &buffer);
 	if(status != 0) err(EX_NOINPUT, "while checking file '%s' in get_file()", file_name);
 	fd = open(file_name, O_RDONLY);
 	if(fd == -1) err(EX_IOERR, "while opening file '%s' in get_file()", file_name); 
-	cat(fd, no_buf, buffer.st_size);
+	cat(fd, no_buf, buffer.st_size, files_pending);
 	close(fd);
 }
 int main(int argc, char *argv[]){
 	size_t i = 0;
 	char no_buf = 0; //-u option
 	for(i=1; i <= argc; i++){ //step through all the vars, this is more readable than pointer arythmatic
 		if(argv[1] == NULL)
-			cat(STDIN_FILENO, no_buf, BUFF_SIZE); 
+			cat(STDIN_FILENO, no_buf, BUFF_SIZE, argc-i); 
 		else if(argv[i][0] == '-' && argv[i][1] != '\0'){ //if its a command line arg
 			if(argv[i][1] == 'h') errx(EX_OK, "\n%s\n", HELP);
 			else if(argv[i][1] == 'u') no_buf = 1; //required by POSIX, turns off buffered output
 			else errx(EX_USAGE, "while reading command line arg %ld in main(): unknown command line arg '%s'\n", i, argv[i]);
 		} else {
-			for( ; i < argc; i++) get_file(argv[i], no_buf); //step through each arg as if it's a file, even if its a -
+			for( ; i < argc; i++) get_file(argv[i], no_buf, argc-i); //step through each arg as if it's a file, even if its a -
 		}
 	}
 	return EX_OK;