4 files changed, 230 insertions, 0 deletions

diff --git a/8.4/Makefile b/8.4/Makefile
new file mode 100644
index 0000000..fb8a9bb
--- /dev/null
+++ b/8.4/Makefile
@@ -0,0 +1,12 @@
+OBJECTS = main.o stdio.o
+CC = gcc
+CFLAGS = -Wvla -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -fsanitize=address
+
+sneed : $(OBJECTS)
+	$(CC) $(CFLAGS) -o sneed $(OBJECTS)
+
+main.o : stdio.h
+
+.PHONY : clean
+clean :
+	rm -f sneed $(OBJECTS)
diff --git a/8.4/main.c b/8.4/main.c
new file mode 100644
index 0000000..4c5b7b6
--- /dev/null
+++ b/8.4/main.c
@@ -0,0 +1,8 @@
+#include "stdio.h"
+
+int main(void)
+{
+	puts("sneed from sneedio.h (formerly stdio.h)\n");
+
+	return 0;
+}
diff --git a/8.4/stdio.c b/8.4/stdio.c
new file mode 100644
index 0000000..57b90ba
--- /dev/null
+++ b/8.4/stdio.c
@@ -0,0 +1,160 @@
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include "stdio.h"
+
+#define PERMS 0666
+
+FILE _iob[OPN_MAX] = {
+	{0, NULL, NULL, _READ, 0},
+	{0, NULL, NULL, _WRITE, 1},
+	{0, NULL, NULL, _WRITE | _UNBUF, 2}
+};
+
+FILE *fopen(char *name, char *mode)
+{
+	FILE *fp;
+
+	if (*mode != 'r' && *mode != 'w' && *mode != 'a')
+		return NULL;
+	
+	for(fp = _iob; fp < _iob + OPN_MAX; ++fp)
+		if (!(fp->flag & (_READ | _WRITE)))
+			break;
+	if (fp == _iob + OPN_MAX)
+		return NULL;
+
+	if (*mode == 'w') {
+		fp->fd = open(name, O_WRONLY);
+	} else if (*mode == 'a') {
+		if ((fp->fd = open(name, O_WRONLY)) == -1)
+			fp->fd = creat(name, PERMS);
+		lseek(fp->fd, 0L, 2);
+	} else {
+		fp->fd = open(name, O_RDONLY);
+	}
+
+	if (fp->fd == -1) {
+		fp->fd = 0;
+		return NULL;
+	}
+
+	fp->base = fp->ptr = NULL;
+	fp->flag = (*mode == 'r') ? _READ : _WRITE;
+	fp->cnt = 0;
+
+	return fp;
+}
+
+int _fillbuf(FILE *fp)
+{
+	int bufsize;
+
+	if ((fp->flag & (_READ | _EOF | _ERR)) != _READ)
+		return EOF;
+
+	bufsize = (fp->flag & _UNBUF) ? 1 : BUFSIZ;
+	if (fp->base == NULL)
+		if ((fp->base = malloc(bufsize)) == NULL)
+			return EOF;
+	fp->ptr = fp->base;
+
+	fp->cnt = read(fp->fd, fp->base, bufsize);
+	if (--fp->cnt < 0) {
+		if (fp->cnt == -1)
+			fp->flag = _EOF;
+		else // fp->cnt == -2
+			fp->flag = _ERR;
+		fp->cnt = 0;
+		return EOF;
+	}
+
+	return (unsigned char) *fp->ptr++;
+}
+
+int _flushbuf(int c, FILE *fp)
+{
+	int bufsize, nc;
+
+	if ((fp->flag & (_WRITE | _ERR)) != _WRITE)
+		return EOF;
+
+	bufsize = (fp->flag & _UNBUF) ? 1 : BUFSIZ;
+	if (fp->base == NULL) {
+		if ((fp->base = malloc(bufsize)) == NULL)
+			return EOF;
+	} else {
+		nc = fp->ptr - fp->base;
+		if (write(fp->fd, fp->base, nc) != nc) {
+			fp->flag = _ERR;
+			return EOF;
+		}
+	}
+
+	fp->ptr = fp->base;
+	fp->cnt = bufsize - 1;
+	*fp->ptr++ = c;
+
+	return (unsigned char) c;
+}
+
+int fflush(FILE *fp)
+{
+	int rc = 0;
+
+	if (fp < _iob && fp >= _iob + OPN_MAX)
+		return EOF;
+	if (fp->flag & _WRITE)
+		rc = _flushbuf(0, fp);
+
+	fp->ptr = fp->base;
+	fp->cnt = (fp->flag & _UNBUF) ? 1 : BUFSIZ;
+
+	return rc;
+}
+
+
+int fclose(FILE *fp)
+{
+	int rc;
+
+	if ((rc = fflush(fp)) != EOF) {
+		free(fp->base);
+		fp->base = fp->ptr = NULL;
+		fp->flag &= ~(_READ | _WRITE);
+		fp->cnt = 0;
+		close(fp->fd);
+	}
+
+	return rc;
+}
+
+int fseek(FILE *fp, ssize_t os, int origin)
+{
+	int rc = 0;
+
+	if (fp < _iob && fp >= _iob + OPN_MAX)
+		return EOF;
+
+	if (fp->flag & _READ) {
+		if (os == SEEK_CUR)
+			os -= fp->cnt;
+		rc = lseek(fp->fd, os, origin);
+		fp->cnt = 0;
+	} else if (fp->flag & _WRITE) {
+		if ((rc = fflush(fp)) != EOF)
+			rc = lseek(fp->fd, os, origin);
+	}
+
+	return (rc == -1) ? -1 : 0;
+}
+
+int puts(const char *s)
+{
+	while (*s)
+		if (putchar(*s++) == EOF)
+			return EOF;
+	fflush(stdout);
+
+	return 1;
+}
diff --git a/8.4/stdio.h b/8.4/stdio.h
new file mode 100644
index 0000000..37413a2
--- /dev/null
+++ b/8.4/stdio.h
@@ -0,0 +1,50 @@
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stddef.h>
+
+#define EOF	(-1)
+#define BUFSIZ	8192
+#define OPN_MAX	20
+
+typedef struct {
+	int cnt;
+	char *ptr;
+	char *base;
+	int flag;
+	int fd;
+} FILE;
+
+extern FILE _iob[OPN_MAX];
+
+#define stdin	(_iob+0)
+#define stdout	(_iob+1)
+#define stderr	(_iob+2)
+
+enum flags {
+	_READ 	= 1 << 0,
+	_WRITE 	= 1 << 2,
+	_UNBUF	= 1 << 3,
+	_EOF	= 1 << 4,
+	_ERR	= 1 << 5
+};
+
+int _fillbuf(FILE *);
+int _flushbuf(int, FILE *);
+FILE *fopen(char *name, char *mode);
+int fflush(FILE *fp);
+int fseek(FILE *fp, ssize_t os, int whence);
+int fclose(FILE *fp);
+int puts(const char *);
+
+#define feof(p)	  ((p)->flag & _EOF)
+#define ferror(p) ((p)->flag & _ERR)
+#define fileno(p) ((p)->fd)
+
+#define getc(p)	   ((--(p)->cnt >= 0) \
+		? (unsigned char) *(p)->ptr++ : _fillbuf(p))
+#define putc(x, p) ((--(p)->cnt >= 0) \
+		? *(p)->ptr++ = (x) : _flushbuf(x, p))
+
+#define getchar()  getc(stdin)
+#define putchar(x) putc((x), stdout)