io: file: add b_stream support

io/sys/darwin/file.c

@@ -8,6 +8,8 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
@@ -28,29 +30,31 @@ static struct b_object_type file_type = {
 	.t_release = file_release,
 };
 
+#define CHECK_FLAG(v, f) (((v) & (f)) == (f))
+
 static unsigned int b_mode_to_unix_mode(enum b_file_mode mode)
 {
 	unsigned int result = 0;
 
-	if (mode & B_FILE_READ_WRITE) {
+	if (CHECK_FLAG(mode, B_FILE_READ_WRITE)) {
 		result |= O_RDWR;
-	} else if (mode & B_FILE_READ_ONLY) {
+	} else if (CHECK_FLAG(mode, B_FILE_READ_ONLY)) {
 		result |= O_RDONLY;
-	} else if (mode & B_FILE_WRITE_ONLY) {
+	} else if (CHECK_FLAG(mode, B_FILE_WRITE_ONLY)) {
 		result |= O_WRONLY;
 	} else {
-		return 0;
+		return (unsigned int)-1;
 	}
 
-	if (mode & B_FILE_TRUNCATE) {
+	if (CHECK_FLAG(mode, B_FILE_TRUNCATE)) {
 		result |= O_TRUNC;
 	}
 
-	if (mode & B_FILE_CREATE) {
+	if (CHECK_FLAG(mode, B_FILE_CREATE)) {
 		result |= O_CREAT;
 	}
 
-	if ((mode & B_FILE_CREATE_ONLY) == B_FILE_CREATE_ONLY) {
+	if (CHECK_FLAG(mode, B_FILE_CREATE_ONLY)) {
 		result |= O_EXCL;
 	}
 
@@ -64,7 +68,7 @@ enum b_status b_file_open(
 	struct b_path *file_path = b_path_retain((struct b_path *)path);
 	unsigned int flags = b_mode_to_unix_mode(mode);
 
-	if (flags == 0) {
+	if (flags == (unsigned int)-1) {
 		b_path_release(file_path);
 		return B_ERR_INVALID_ARGUMENT;
 	}
@@ -202,6 +206,123 @@ enum b_status b_file_open_shadow(
 	return B_SUCCESS;
 }
 
+enum b_status stream_close(struct b_stream *stream)
+{
+	struct b_file *file = stream->s_ptr;
+	b_file_release(file);
+
+	return B_SUCCESS;
+}
+
+enum b_status stream_getc(struct b_stream *stream, int *out)
+{
+	struct b_file *file = stream->s_ptr;
+	char c;
+	size_t nr_read = 0;
+
+	enum b_status status
+		= b_file_read(file, stream->s_cursor, sizeof c, &c, &nr_read);
+	if (status != B_SUCCESS) {
+		return status;
+	}
+
+	if (nr_read == 0) {
+		return B_ERR_NO_DATA;
+	}
+
+	stream->s_cursor += nr_read;
+	*out = c;
+	return B_SUCCESS;
+}
+
+enum b_status stream_read(
+	struct b_stream *stream, unsigned char *buf, size_t max, size_t *nr_read)
+{
+	struct b_file *file = stream->s_ptr;
+
+	enum b_status status
+		= b_file_read(file, stream->s_cursor, max, buf, nr_read);
+
+	stream->s_cursor += *nr_read;
+
+	return status;
+}
+
+enum b_status stream_write(
+	struct b_stream *stream, const unsigned char *buf, size_t count,
+	size_t *nr_written)
+{
+	struct b_file *file = stream->s_ptr;
+
+	enum b_status status
+		= b_file_write(file, stream->s_cursor, count, buf, nr_written);
+
+	stream->s_cursor += *nr_written;
+
+	return status;
+}
+
+enum b_status stream_seek(
+	struct b_stream *stream, long long offset, b_stream_seek_origin origin)
+{
+	b_seek_basis basis;
+	switch (origin) {
+	case B_STREAM_SEEK_START:
+		basis = B_SEEK_BEGINNING;
+		break;
+	case B_STREAM_SEEK_CURRENT:
+		basis = B_SEEK_CURRENT;
+		break;
+	case B_STREAM_SEEK_END:
+		basis = B_SEEK_END;
+		break;
+	default:
+		return B_ERR_INVALID_ARGUMENT;
+	}
+
+	struct b_file *file = stream->s_ptr;
+
+	enum b_status status = b_file_seek(file, offset, basis);
+	if (!B_OK(status)) {
+		return status;
+	}
+
+	return b_file_cursor(file, &stream->s_cursor);
+}
+
+enum b_status b_file_open_stream(struct b_file *file, struct b_stream **out)
+{
+	struct b_stream *stream = malloc(sizeof *stream);
+	if (!stream) {
+		return B_ERR_NO_MEMORY;
+	}
+
+	memset(stream, 0x0, sizeof *stream);
+
+	if (file->mode & B_FILE_READ_ONLY) {
+		stream->s_mode |= B_STREAM_READ;
+	}
+
+	if (file->mode & B_FILE_WRITE_ONLY) {
+		stream->s_mode |= B_STREAM_WRITE;
+	}
+
+	if (file->mode & B_FILE_BINARY) {
+		stream->s_mode |= B_STREAM_BINARY;
+	}
+
+	stream->s_ptr = b_file_retain(file);
+	stream->s_close = stream_close;
+	stream->s_getc = stream_getc;
+	stream->s_read = stream_read;
+	stream->s_write = stream_write;
+	stream->s_seek = stream_seek;
+
+	*out = stream;
+
+	return B_SUCCESS;
+}
+
 enum b_status b_file_stat(struct b_file *file, struct b_file_info *out)
 {
 	struct stat st;