1 files changed, 153 insertions, 0 deletions
diff --git a/libpkgconf/output.c b/libpkgconf/output.c
new file mode 100644
index 000000000000..fc7ab85ea2e1
--- /dev/null
+++ b/libpkgconf/output.c
@@ -0,0 +1,153 @@
+/*
+ * output.c
+ * I/O abstraction layer
+ *
+ * SPDX-License-Identifier: pkgconf
+ *
+ * Copyright (c) 2025 pkgconf authors (see AUTHORS).
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <libpkgconf/stdinc.h>
+#include <libpkgconf/libpkgconf.h>
+
+bool
+pkgconf_output_putbuf(pkgconf_output_t *output, pkgconf_output_stream_t stream, const pkgconf_buffer_t *buffer, bool newline)
+{
+	bool ret;
+	pkgconf_buffer_t buf = PKGCONF_BUFFER_INITIALIZER;
+
+	if (pkgconf_buffer_len(buffer) != 0)
+		pkgconf_buffer_append(&buf, pkgconf_buffer_str(buffer));
+
+	if (newline)
+		pkgconf_buffer_push_byte(&buf, '\n');
+
+	ret = output->write(output, stream, &buf);
+	pkgconf_buffer_finalize(&buf);
+
+	return ret;
+}
+
+bool
+pkgconf_output_puts(pkgconf_output_t *output, pkgconf_output_stream_t stream, const char *str)
+{
+	bool ret;
+	pkgconf_buffer_t buf = PKGCONF_BUFFER_INITIALIZER;
+
+	pkgconf_buffer_append(&buf, str);
+	pkgconf_buffer_push_byte(&buf, '\n');
+	ret = output->write(output, stream, &buf);
+	pkgconf_buffer_finalize(&buf);
+
+	return ret;
+}
+
+bool
+pkgconf_output_fmt(pkgconf_output_t *output, pkgconf_output_stream_t stream, const char *fmt, ...)
+{
+	bool ret;
+	va_list va;
+
+	va_start(va, fmt);
+	ret = pkgconf_output_vfmt(output, stream, fmt, va);
+	va_end(va);
+
+	return ret;
+}
+
+bool
+pkgconf_output_vfmt(pkgconf_output_t *output, pkgconf_output_stream_t stream, const char *fmt, va_list src_va)
+{
+	va_list va;
+	bool ret;
+	pkgconf_buffer_t buf = PKGCONF_BUFFER_INITIALIZER;
+
+	va_copy(va, src_va);
+	pkgconf_buffer_append_vfmt(&buf, fmt, va);
+	va_end(va);
+
+	ret = output->write(output, stream, &buf);
+	pkgconf_buffer_finalize(&buf);
+
+	return ret;
+}
+
+static bool
+pkgconf_output_stdio_write(pkgconf_output_t *output, pkgconf_output_stream_t stream, const pkgconf_buffer_t *buffer)
+{
+	(void) output;
+
+	FILE *target = stream == PKGCONF_OUTPUT_STDERR ? stderr : stdout;
+
+	if (buffer != NULL)
+	{
+		const char *str = pkgconf_buffer_str(buffer);
+		size_t size = pkgconf_buffer_len(buffer);
+
+		if (size > 0 && !fwrite(str, size, 1, target))
+			return false;
+	}
+
+	fflush(target);
+	return true;
+}
+
+static pkgconf_output_t pkgconf_default_output = {
+	.privdata = NULL,
+	.write = pkgconf_output_stdio_write,
+};
+
+pkgconf_output_t *
+pkgconf_output_default(void)
+{
+	return &pkgconf_default_output;
+}
+
+/*
+ * !doc
+ *
+ * .. c:function:: bool pkgconf_output_file_vfmt(FILE *f, const char *fmt, va_list va)
+ *
+ *    Wrapper around :code:`vfprintf` that returns a boolean.
+ *
+ *    :param FILE *f: Pointer to an open `FILE` pointer.
+ *    :param: const char *fmt: Format string.
+ *    :param va_list va: Variable list.
+ *    :return: :code:`true` on success, :code:`false` on failure.
+ */
+bool
+pkgconf_output_file_vfmt(FILE *f, const char *fmt, va_list va)
+{
+	int ret = vfprintf(f, fmt, va);
+	return ret >= 0;
+}
+
+/*
+ * !doc
+ *
+ * .. c:function:: bool pkgconf_output_file_fmt(FILE *f, const char *fmt, va_list va)
+ *
+ *    Wrapper around :code:`fprintf` that returns a boolean.
+ *
+ *    :param FILE *f: Pointer to an open `FILE` pointer.
+ *    :param: const char *fmt: Format string.
+ *    :return: :code:`true` on success, :code:`false` on failure.
+ */
+bool
+pkgconf_output_file_fmt(FILE *f, const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	bool ret = pkgconf_output_file_vfmt(f, fmt, va);
+	va_end(va);
+
+	return ret;
+}