Implemented fgets() and enhanced IO buffering

photon/libc/include/stdio.h

@@ -11,6 +11,8 @@
 #define FILENAME_MAX 1024
 #endif
 
+#define BUFSIZ __FIO_BUFSZ
+
 #define SEEK_SET __SEEK_SET
 #define SEEK_CUR __SEEK_CUR
 #define SEEK_END __SEEK_END
@@ -41,6 +43,7 @@ extern int fileno(FILE *fp);
 extern int fputs(const char *str, FILE *fp);
 extern int fputc(int c, FILE *fp);
 extern int fgetc(FILE *fp);
+extern char *fgets(char *restrict str, int count, FILE *restrict fp);
 extern int putchar(int c);
 
 extern int ungetc(int c, FILE *fp);

photon/libc/stdio/fgetc.c

@@ -4,8 +4,8 @@
 int fgetc(FILE *fp)
 {
     char ch = 0;
-    __fio_read(fp, &ch, 1);
-    if (__fio_error(fp)) {
+    unsigned int r = __fio_read(fp, &ch, 1);
+    if (r == 0 || __fio_error(fp) || __fio_eof(fp)) {
         return EOF;
     }
 

photon/libc/stdio/fgets.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+
+char *fgets(char *restrict str, int count, FILE *restrict fp)
+{
+    if (count < 1) {
+        return NULL;
+    }
+
+    if (count == 1) {
+        str[0] = '\0';
+        return str;
+    }
+
+    int r = 0;
+
+    while (1) {
+        int c = fgetc(fp);
+        if (c == EOF) {
+            str[r] = '\0';
+            break;
+        }
+
+        str[r++] = c;
+
+        if (r == count - 1 || c == '\n') {
+            str[r] = '\0';
+            break;
+        }
+    }
+
+    return r > 0 ? str : NULL;
+}

photon/libc/stdio/ungetc.c

@@ -3,6 +3,10 @@
 
 int ungetc(int c, FILE *fp)
 {
+    if (c == EOF) {
+        return EOF;
+    }
+
     int res = __fio_ungetc(fp, c);
     return res == -1 ? EOF : c;
 }

photon/libc/sys/horizon/__fio.h

@@ -8,11 +8,12 @@ extern "C" {
 #endif
 
 struct __io_file {
-    char buf[__FIO_BUFSZ];
-    unsigned long buf_idx;
-    int fd;
-    char err;
-    char unget;
+    char in_buf[__FIO_BUFSZ];
+    char out_buf[__FIO_BUFSZ];
+    unsigned long in_buf_ptr, in_buf_len;
+    unsigned long out_buf_len;
+    int fd, unget;
+    char err, eof;
 };
 
 extern int __fileno(struct __io_file *f);
@@ -21,6 +22,7 @@ extern unsigned int __fio_read(struct __io_file *f, char *buf, unsigned int sz);
 extern unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz);
 extern unsigned int __fio_flush(struct __io_file *f);
 extern int __fio_error(struct __io_file *f);
+extern int __fio_eof(struct __io_file *f);
 extern int __fio_ungetc(struct __io_file *f, char c);
 
 extern int __fio_fopen(const char *path, const char *mode, struct __io_file *out);

photon/libc/sys/horizon/fio.c

@@ -1,5 +1,5 @@
-#include <magenta/misc.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 #include "sys/types.h"
 #include "__fio.h"
@@ -13,6 +13,20 @@ static int flags_from_mode(const char *r)
     return 0;
 }
 
+static int refill(struct __io_file *fp)
+{
+    ssize_t err = read(fp->fd, fp->in_buf, sizeof fp->in_buf);
+    if (err < 0) {
+        fp->err = 1;
+        return 0;
+    }
+
+    fp->in_buf_ptr = 0;
+    fp->in_buf_len = err;
+
+    return err;
+}
+
 FILE *__get_stdio_file(int i)
 {
     switch (i) {
@@ -36,17 +50,37 @@ void __fio_init(int in, int out, int err)
 
 int __fio_fopen(const char *path, const char *mode, struct __io_file *fp)
 {
+    /* TODO */
+    int fd = open(path, 0);
+    if (fd == -1) {
         return -1;
+    }
+
+    fp->fd = fd;
+
+    return 0;
 }
 
 int __fio_fclose(struct __io_file *fp)
 {
+    if (fp->fd == -1) {
         return -1;
+    }
+
+    close(fp->fd);
+    fp->fd = -1;
+    return 0;
 }
 
 int __fio_fdopen(int fd, const char *mode, struct __io_file *fp)
 {
+    if (fd == -1) {
         return -1;
+    }
+
+    fp->fd = fd;
+
+    return 0;
 }
 
 int __fileno(struct __io_file *f)
@@ -56,23 +90,77 @@ int __fileno(struct __io_file *f)
 
 unsigned int __fio_read(struct __io_file *f, char *buf, unsigned int sz)
 {
-    ssize_t err = read(f->fd, buf, sz);
-    if (err < 0) {
-        f->err = 1;
+    if (sz == 0) {
         return 0;
     }
 
-    return err;
+    size_t r = 0;
+    char *out = buf;
+
+    if (f->unget) {
+        *out++ = f->unget;
+        f->unget = 0;
+        r++;
+        sz--;
+    }
+
+    size_t available = f->in_buf_len - f->in_buf_ptr;
+
+    size_t bufread = sz;
+    if (bufread > available) {
+        bufread = available;
+    }
+
+    memcpy(out, f->in_buf + f->in_buf_ptr, bufread);
+    f->in_buf_ptr += bufread;
+    out += bufread;
+    sz -= bufread;
+    r += bufread;
+
+    if (sz == 0) {
+        return r;
+    }
+
+    while (1) {
+        refill(f);
+
+        available = f->in_buf_len - f->in_buf_ptr;
+        if (available == 0) {
+            f->eof = 1;
+            break;
+        }
+
+        bufread = sz;
+        if (bufread > available) {
+            bufread = available;
+        }
+
+        memcpy(out, f->in_buf + f->in_buf_ptr, bufread);
+        f->in_buf_ptr += bufread;
+        out += bufread;
+        sz -= bufread;
+        r += bufread;
+
+        if (sz == 0 || f->err || f->eof) {
+            break;
+        }
+    }
+
+    if (sz > 0) {
+        f->eof = 1;
+    }
+
+    return r;
 }
 
 unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz)
 {
     for (unsigned int i = 0; i < sz; i++) {
-        if (f->buf_idx >= __FIO_BUFSZ) {
+        if (f->out_buf_len >= __FIO_BUFSZ) {
             __fio_flush(f);
         }
 
-        f->buf[f->buf_idx++] = buf[i];
+        f->out_buf[f->out_buf_len++] = buf[i];
         if (buf[i] == '\n') {
             __fio_flush(f);
         }
@@ -83,18 +171,23 @@ unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz)
 
 int __fio_ungetc(struct __io_file *f, char c)
 {
+    if (f->unget) {
+        return -1;
+    }
+
+    f->unget = c;
     return 0;
 }
 
 unsigned int __fio_flush(struct __io_file *f)
 {
-    ssize_t res = write(f->fd, f->buf, f->buf_idx);
-    if (res != f->buf_idx) {
+    ssize_t res = write(f->fd, f->out_buf, f->out_buf_len);
+    if (res != f->out_buf_len) {
         f->err = 1;
     }
 
-    size_t flushed = f->buf_idx;
-    f->buf_idx = 0;
+    size_t flushed = f->out_buf_len;
+    f->out_buf_len = 0;
     return flushed;
 }
 
@@ -102,3 +195,8 @@ int __fio_error(struct __io_file *f)
 {
     return f->err != 0;
 }
+
+int __fio_eof(struct __io_file *f)
+{
+    return f->eof != 0;
+}

photon/libc/sys/horizon/init.c

@@ -240,6 +240,8 @@ int __crt_init(mx_handle_t bootstrap)
     dbg_log("calling main\n");
     int ret = main(msg->args_num, argv);
 
+    fflush(stdout);
+    fflush(stderr);
     __crt_run_atexit();
     mio_fd_cleanup();
     mio_fs_cleanup();