Add a more usefull getline-like function to libfstream

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 118 insertions, 0 deletions

diff --git a/lib/fstream/get_line.c b/lib/fstream/get_line.c
new file mode 100644
index 0000000..f7e0b59
--- /dev/null
+++ b/lib/fstream/get_line.c
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * get_line.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "internal.h"
+
+static void ltrim(char *buffer)
+{
+	size_t i = 0;
+
+	while (isspace(buffer[i]))
+		++i;
+
+	if (i > 0)
+		memmove(buffer, buffer + i, strlen(buffer + i) + 1);
+}
+
+static void rtrim(char *buffer)
+{
+	size_t i = strlen(buffer);
+
+	while (i > 0 && isspace(buffer[i - 1]))
+		--i;
+
+	buffer[i] = '\0';
+}
+
+static size_t trim(char *buffer, int flags)
+{
+	if (flags & ISTREAM_LINE_LTRIM)
+		ltrim(buffer);
+
+	if (flags & ISTREAM_LINE_RTRIM)
+		rtrim(buffer);
+
+	return strlen(buffer);
+}
+
+int istream_get_line(istream_t *strm, char **out,
+		     size_t *line_num, int flags)
+{
+	char *line = NULL, *new;
+	size_t i, line_len = 0;
+	bool have_line = false;
+
+	*out = NULL;
+
+	for (;;) {
+		if (istream_precache(strm))
+			return -1;
+
+		if (strm->buffer_used == 0) {
+			if (line_len == 0)
+				goto out_eof;
+
+			line_len = trim(line, flags);
+
+			if (line_len == 0 &&
+			    (flags & ISTREAM_LINE_SKIP_EMPTY)) {
+				goto out_eof;
+			}
+			break;
+		}
+
+		for (i = 0; i < strm->buffer_used; ++i) {
+			if (strm->buffer[i] == '\n')
+				break;
+		}
+
+		if (i < strm->buffer_used) {
+			have_line = true;
+			strm->buffer_offset = i + 1;
+
+			if (i > 0 && strm->buffer[i - 1] == '\r')
+				--i;
+		} else {
+			strm->buffer_offset = i;
+		}
+
+		new = realloc(line, line_len + i + 1);
+		if (new == NULL)
+			goto fail_errno;
+
+		line = new;
+		memcpy(line + line_len, strm->buffer, i);
+		line_len += i;
+		line[line_len] = '\0';
+
+		if (have_line) {
+			line_len = trim(line, flags);
+
+			if (line_len == 0 &&
+			    (flags & ISTREAM_LINE_SKIP_EMPTY)) {
+				free(line);
+				line = NULL;
+				have_line = false;
+				*line_num += 1;
+				continue;
+			}
+			break;
+		}
+	}
+
+	*out = line;
+	return 0;
+fail_errno:
+	fprintf(stderr, "%s: " PRI_SZ ": %s.\n", strm->get_filename(strm),
+		*line_num, strerror(errno));
+	free(line);
+	*out = NULL;
+	return -1;
+out_eof:
+	free(line);
+	*out = NULL;
+	return 1;
+}