Data commit

Task/File-input-output/C/file-input-output-1.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  FILE *in, *out;
+  int c;
+
+  in = fopen("input.txt", "r");
+  if (!in) {
+    fprintf(stderr, "Error opening input.txt for reading.\n");
+    return 1;
+  }
+
+  out = fopen("output.txt", "w");
+  if (!out) {
+    fprintf(stderr, "Error opening output.txt for writing.\n");
+    fclose(in);
+    return 1;
+  }
+
+  while ((c = fgetc(in)) != EOF) {
+    fputc(c, out);
+  }
+
+  fclose(out);
+  fclose(in);
+  return 0;
+}

Task/File-input-output/C/file-input-output-2.c

@@ -0,0 +1,36 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+/* we just return a yes/no status; caller can check errno */
+int copy_file(const char *in, const char *out)
+{
+	int ret = 0;
+	int fin, fout;
+	ssize_t len;
+	char *buf[4096]; /* buffer size, some multiple of block size preferred */
+	struct stat st;
+
+	if ((fin  = open(in,  O_RDONLY)) == -1) return 0;
+	if (fstat(fin, &st)) goto bail;
+
+	/* open output with same permission */
+	fout = open(out, O_WRONLY|O_CREAT|O_TRUNC, st.st_mode & 0777);
+	if (fout == -1) goto bail;
+
+	while ((len = read(fin, buf, 4096)) > 0)
+		write(fout, buf, len);
+
+	ret = len ? 0 : 1; /* last read should be 0 */
+
+bail:	if (fin != -1)  close(fin);
+	if (fout != -1) close(fout);
+	return ret;
+}
+
+int main()
+{
+	copy_file("infile", "outfile");
+	return 0;
+}

Task/File-input-output/C/file-input-output-3.c

@@ -0,0 +1,23 @@
+int copy_file(const char *in, const char *out)
+{
+	int ret = 0;
+	int fin, fout;
+	char *bi;
+	struct stat st;
+
+	if ((fin  = open(in,  O_RDONLY)) == -1) return 0;
+	if (fstat(fin, &st)) goto bail;
+
+	fout = open(out, O_WRONLY|O_CREAT|O_TRUNC, st.st_mode & 0777);
+	if (fout == -1) goto bail;
+
+	bi = mmap(0, st.st_size, PROT_READ, MAP_PRIVATE, fin,  0);
+
+	ret = (bi == (void*)-1)
+		? 0 : (write(fout, bi, st.st_size) == st.st_size);
+
+bail:	if (fin != -1)  close(fin);
+	if (fout != -1) close(fout);
+	if (bi != (void*)-1) munmap(bi, st.st_size);
+	return ret;
+}