From 4b49eed6098881fbde1f6c7728c1346fc8366979 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Fri, 4 Mar 2016 10:36:08 +1300
Subject: Switch to fopen/fread etc

Not quite finished yet -- this does things with stdin I didn't expect,
like not printing it line-by-line, and requiring two EOFs for some
reason.
---
 Makefile |  4 ++--
 cat.h    |  2 +-
 cfd.c    | 30 ------------------------------
 cfn.c    | 13 +++++++------
 cfp.c    | 33 +++++++++++++++++++++++++++++++++
 main.c   |  4 ++--
 6 files changed, 45 insertions(+), 41 deletions(-)
 delete mode 100644 cfd.c
 create mode 100644 cfp.c

diff --git a/Makefile b/Makefile
index 81db4b5..e373493 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,8 @@
 CC = gcc
 CFLAGS = -Wall -Wpedantic -ansi -pedantic-errors
 
-cat : main.o cfn.o cfd.o 
-	$(CC) $(CFLAGS) -o cat main.o cfn.o cfd.o
+cat : main.o cfn.o cfp.o
+	$(CC) $(CFLAGS) -o cat main.o cfn.o cfp.o
 
 clean :
 	rm -f -- *.o cat
diff --git a/cat.h b/cat.h
index 2a2e494..da5e7ed 100644
--- a/cat.h
+++ b/cat.h
@@ -19,7 +19,7 @@
 /* Function prototypes so that I can refer to these functions in main() before
  * I actually define them */
 int cfn(const char *fn, void *buf);
-int cfd(int fd, void *buf);
+int cfp(FILE *fp, void *buf);
 
 #endif
 
diff --git a/cfd.c b/cfd.c
deleted file mode 100644
index 9e8baa6..0000000
--- a/cfd.c
+++ /dev/null
@@ -1,30 +0,0 @@
-#include "cat.h"
-
-/* Function writes the contents of an opened file descriptor to stdout */
-int cfd(int fd, void *buf) {
-    int br;
-
-    /* Use the buffer to read the file in blocks, writing each block to stdout
-     * as we go */
-    while ((br = read(fd, buf, BUFLEN)) > 0) {
-        fwrite(buf, 1, br, stdout);
-    }
-
-    /* If the last return value for br() was -1, there was an error; 0 is what
-     * we expect */
-    if (br == -1) {
-        perror(__FUNCTION__);
-        return -1;
-    }
-
-    /* Force a write of any still-buffered data to stdout */
-    if (fflush(stdout) != 0) {
-        perror(__FUNCTION__);
-        return -1;
-    }
-
-    /* Return success, since apparently nothing went wrong before we got here
-     * */
-    return 0;
-}
-
diff --git a/cfn.c b/cfn.c
index 9c04fb8..b830f54 100644
--- a/cfn.c
+++ b/cfn.c
@@ -3,10 +3,11 @@
 /* Function opens and writes the contents of a named file to stdout;
  * effectively a wrapper around cfd() */
 int cfn(const char *fn, void *buf) {
-    int fd;
+    FILE *fp;
+    int cfpr;
 
     /* Open the file to get a read-only file descriptor */
-    if ((fd = open(fn, O_RDONLY)) == -1) {
+    if ((fp = fopen(fn, "r")) == NULL) {
         perror(__FUNCTION__);
         return -1;
     }
@@ -14,15 +15,15 @@ int cfn(const char *fn, void *buf) {
     /* Pass the opened descriptor to cfd() to read it; we keep going even if
      * there are problems, because we need the descriptor closed even if we
      * couldn't read it */
-    cfd(fd, buf);
+    cfpr = cfp(fp, buf);
 
     /* Close the descriptor, since we should now be done with it */
-    if (close(fd) == -1) {
+    if (fclose(fp) != 0) {
         perror(__FUNCTION__);
         return -1;
     }
 
-    /* Done, assume success */
-    return 0;
+    /* Done, return the result of the cfp() call */
+    return cfpr;
 }
 
diff --git a/cfp.c b/cfp.c
new file mode 100644
index 0000000..9d0d5a7
--- /dev/null
+++ b/cfp.c
@@ -0,0 +1,33 @@
+#include "cat.h"
+
+/* Function writes the contents of an opened file descriptor to stdout */
+int cfp(FILE *fp, void *buf) {
+    int br;
+
+    /* Use the buffer to read the file in blocks, writing each block to stdout
+     * as we go */
+    while ((br = fread(buf, 1, BUFLEN, fp)) > 0) {
+        if (fwrite(buf, 1, br, stdout) == 0) {
+            perror(__FUNCTION__);
+            return -1;
+        }
+    }
+
+    /* If the last return value for br() was -1, there was an error; 0 is what
+     * we expect */
+    if (ferror(fp) != 0 || ferror(stdout) != 0) {
+        perror(__FUNCTION__);
+        return -1;
+    }
+
+    /* Force a write of any still-buffered data to stdout */
+    if (fflush(stdout) != 0) {
+        perror(__FUNCTION__);
+        return -1;
+    }
+
+    /* Return success, since apparently nothing went wrong before we got here
+     * */
+    return 0;
+}
+
diff --git a/main.c b/main.c
index 620cc41..51ee707 100644
--- a/main.c
+++ b/main.c
@@ -25,7 +25,7 @@ int main(int argc, const char *argv[]) {
 
             /* If the filename is the special case of -, we emit stdin */
             if (strncmp(argv[i], "-", 1) == 0) {
-                if (cfd(0, buf) == -1) {
+                if (cfp(stdin, buf) == -1) {
                     exv = EXIT_FAILURE;
                 }
 
@@ -40,7 +40,7 @@ int main(int argc, const char *argv[]) {
     /* If there were no arguments, we assume the user wants us to read from
      * stdin, which should already be opened */
     } else {
-        if (cfd(0, buf) == -1) {
+        if (cfp(stdin, buf) == -1) {
             exv = EXIT_FAILURE;
         }
     }
-- 
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