Split into two files1.0.0-rc1

1 files changed, 69 insertions, 0 deletions

diff --git a/iohelper.c b/iohelper.c
new file mode 100644
index 0000000..de5ad34
--- /dev/null
+++ b/iohelper.c
@@ -0,0 +1,69 @@
+/*
+ * iohelper.c
+ * 
+ * Alexander Occhipinti
+ * Student ID: 29994705
+ * Created: 10 Sep 2020
+ * Last Modified: 10 Sep 2020
+ * 
+ * iohelper is a small, simple library containing light wrapper functions to Linux system calls.
+ * The functions in iohelper are similar to what would normally be provided in C's stdio.h library.
+ *  
+*/
+
+#include <unistd.h>
+#include <sys/file.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include "iohelper.h"
+
+/*
+ * Prints a given string to stdout. Returns nothing.
+*/
+void to_stdout(char *string) {
+    write(1, string, strlen(string));
+}
+
+/*
+ * Prints a given string to stderr. Returns nothing.
+*/
+void to_stderr(char *string) {
+    write(2, string, strlen(string));
+}
+
+/*
+ * Given a file path and open() flags, open a file
+ * Catches openning errors, prints an error to stderr when an error occurs and exits 
+ * Returns a file descriptor of the open file. Needs to be closed afterwards.
+*/
+int open_file(char *path, int flags){
+        // Read the input file
+    int fd;
+    if ((fd = open(path, flags, NEW_FILE_PERMS)) < 0){
+        int error = errno;
+        to_stderr(path);
+        to_stderr(" could not be opened: ");
+        to_stderr(strerror(error));
+        to_stderr("\n");
+        // Exit as error 2 if the file exists and can not be overwriten
+        if (errno == EEXIST) exit(2);
+        exit(1); // Exit with 1 otherwise
+    }
+    return fd;
+}
+
+/*
+ * Given a source file descriptor open for reading, 
+ * put all of its contents in the destination file descriptor open for writing.
+ * 
+ * Useful for transferring data between files or stdin/stdout/stderr
+*/
+void file_into_file(int source_fd, int dest_fd){
+    int bytes_read;
+    char buffer[FILE_BUF_SIZE];
+    while ((bytes_read = read(source_fd, buffer, FILE_BUF_SIZE))) {
+        write(dest_fd, buffer, bytes_read);
+    }
+
+}
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