Cleanup: move memory/stdio streams to libcommon

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

3 files changed, 217 insertions, 3 deletions

diff --git a/lib/common/Makemodule.am b/lib/common/Makemodule.am
index 7c07d48..9438d3a 100644
--- a/lib/common/Makemodule.am
+++ b/lib/common/Makemodule.am
@@ -6,7 +6,8 @@ libcommon_a_SOURCES = include/common.h include/simple_writer.h \
 	lib/common/src/writer/init.c lib/common/src/writer/cleanup.c \
 	lib/common/src/writer/serialize_fstree.c lib/common/src/writer/finish.c\
 	lib/common/src/fstree_cli.c lib/common/src/perror.c \
-	lib/common/src/dir_tree.c lib/common/src/read_tree.c
+	lib/common/src/dir_tree.c lib/common/src/read_tree.c \
+	lib/common/src/stream.c
 libcommon_a_CFLAGS = $(AM_CFLAGS) $(LZO_CFLAGS)
 
 if WITH_LZO
@@ -15,14 +16,18 @@ endif
 
 noinst_LIBRARIES += libcommon.a
 
+test_istream_mem_SOURCES = lib/common/test/istream_mem.c
+test_istream_mem_LDADD = libcommon.a libsquashfs.la libcompat.a
+test_istream_mem_CPPFLAGS = $(AM_CPPFLAGS)
+
 test_fstree_cli_SOURCES = lib/common/test/fstree_cli.c
-test_fstree_cli_LDADD = libcommon.a libio.a libutil.a libcompat.a
+test_fstree_cli_LDADD = libcommon.a libutil.a libcompat.a
 
 test_get_node_path_SOURCES = lib/common/test/get_node_path.c
 test_get_node_path_LDADD = libcommon.a libsquashfs.la libcompat.a
 
 LIBCOMMON_TESTS = \
-	test_fstree_cli test_get_node_path
+	test_istream_mem test_fstree_cli test_get_node_path
 
 check_PROGRAMS += $(LIBCOMMON_TESTS)
 TESTS += $(LIBCOMMON_TESTS)
diff --git a/lib/common/src/stream.c b/lib/common/src/stream.c
new file mode 100644
index 0000000..a557360
--- /dev/null
+++ b/lib/common/src/stream.c
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * mem.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "compat.h"
+#include "common.h"
+#include "sqfs/io.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#if defined(_WIN32) || defined(__WINDOWS__)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#else
+#include <unistd.h>
+#define STD_INPUT_HANDLE STDIN_FILENO
+#define STD_OUTPUT_HANDLE STDOUT_FILENO
+#define GetStdHandle(hnd) hnd
+#endif
+
+typedef struct {
+	sqfs_istream_t base;
+
+	sqfs_u8 *buffer;
+	size_t bufsz;
+
+	const void *data;
+	size_t size;
+	size_t offset;
+	size_t visible;
+
+	char *name;
+} mem_istream_t;
+
+static int mem_get_buffered_data(sqfs_istream_t *strm, const sqfs_u8 **out,
+				 size_t *size, size_t want)
+{
+	mem_istream_t *mem = (mem_istream_t *)strm;
+	size_t have = mem->size - mem->offset;
+
+	if (have > mem->bufsz)
+		have = mem->bufsz;
+
+	if (want > have)
+		want = have;
+
+	if (mem->visible == 0 || mem->visible < want) {
+		memcpy(mem->buffer + mem->visible,
+		       (const char *)mem->data + mem->offset + mem->visible,
+		       have - mem->visible);
+		mem->visible = have;
+	}
+
+	*out = mem->buffer;
+	*size = mem->visible;
+	return (mem->visible == 0) ? 1 : 0;
+}
+
+static void mem_advance_buffer(sqfs_istream_t *strm, size_t count)
+{
+	mem_istream_t *mem = (mem_istream_t *)strm;
+
+	assert(count <= mem->visible);
+
+	if (count > 0 && count < mem->visible)
+		memmove(mem->buffer, mem->buffer + count, mem->visible - count);
+
+	mem->offset += count;
+	mem->visible -= count;
+
+	if (mem->visible < mem->bufsz) {
+		memset(mem->buffer + mem->visible, 0,
+		       mem->bufsz - mem->visible);
+	}
+}
+
+static const char *mem_in_get_filename(sqfs_istream_t *strm)
+{
+	return ((mem_istream_t *)strm)->name;
+}
+
+static void mem_in_destroy(sqfs_object_t *obj)
+{
+	free(((mem_istream_t *)obj)->buffer);
+	free(((mem_istream_t *)obj)->name);
+	free(obj);
+}
+
+sqfs_istream_t *istream_memory_create(const char *name, size_t bufsz,
+				      const void *data, size_t size)
+{
+	mem_istream_t *mem = calloc(1, sizeof(*mem));
+	sqfs_istream_t *strm = (sqfs_istream_t *)mem;
+
+	if (mem == NULL)
+		return NULL;
+
+	sqfs_object_init(mem, mem_in_destroy, NULL);
+
+	mem->name = strdup(name);
+	if (mem->name == NULL)
+		return sqfs_drop(mem);
+
+	mem->buffer = malloc(bufsz);
+	if (mem->buffer == NULL)
+		return sqfs_drop(mem);
+
+	mem->data = data;
+	mem->size = size;
+	mem->bufsz = bufsz;
+	strm->get_buffered_data = mem_get_buffered_data;
+	strm->advance_buffer = mem_advance_buffer;
+	strm->get_filename = mem_in_get_filename;
+	return strm;
+}
+
+int istream_open_stdin(sqfs_istream_t **out)
+{
+	sqfs_file_handle_t hnd = GetStdHandle(STD_INPUT_HANDLE);
+
+	return sqfs_istream_open_handle(out, "stdin", hnd, 0);
+}
+
+int ostream_open_stdout(sqfs_ostream_t **out)
+{
+	sqfs_file_handle_t hnd = GetStdHandle(STD_OUTPUT_HANDLE);
+
+	return sqfs_ostream_open_handle(out, "stdout", hnd,
+					SQFS_FILE_OPEN_NO_SPARSE);
+}
diff --git a/lib/common/test/istream_mem.c b/lib/common/test/istream_mem.c
new file mode 100644
index 0000000..2213168
--- /dev/null
+++ b/lib/common/test/istream_mem.c
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * istream_mem.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "util/test.h"
+#include "sqfs/io.h"
+#include "common.h"
+
+static const size_t end0 = 449;	/* region 1: filled with 'A' */
+static const size_t end1 = 521;	/* region 2: filled with 'B' */
+static const size_t end2 = 941;	/* region 3: filled with 'C' */
+
+static unsigned char data[941];
+
+static unsigned char byte_at_offset(size_t off)
+{
+	if (off < end0)
+		return 'A';
+	if (off < end1)
+		return 'B';
+	return 'C';
+}
+
+static void init_buffer(void)
+{
+	for (size_t i = 0; i < end2; ++i)
+		data[i] = byte_at_offset(i);
+}
+
+int main(int argc, char **argv)
+{
+	size_t i, diff, size;
+	bool eat_all = true;
+	const sqfs_u8 *ptr;
+	sqfs_istream_t *in;
+	int ret;
+	(void)argc; (void)argv;
+
+	init_buffer();
+
+	in = istream_memory_create("memstream.txt", 61, data, sizeof(data));
+	TEST_NOT_NULL(in);
+	TEST_EQUAL_UI(((sqfs_object_t *)in)->refcount, 1);
+
+	TEST_STR_EQUAL(in->get_filename(in), "memstream.txt");
+
+	for (i = 0; i < end2; i += diff) {
+		ret = in->get_buffered_data(in, &ptr, &size, 61);
+		TEST_EQUAL_I(ret, 0);
+
+		if ((end2 - i) >= 61) {
+			TEST_NOT_NULL(ptr);
+			TEST_EQUAL_UI(size, 61);
+		} else {
+			TEST_NOT_NULL(ptr);
+			TEST_EQUAL_UI(size, (end2 - i));
+		}
+
+		for (size_t j = 0; j < size; ++j) {
+			TEST_EQUAL_UI(ptr[j], byte_at_offset(i + j));
+		}
+
+		diff = eat_all ? size : (size / 2);
+		eat_all = !eat_all;
+		in->advance_buffer(in, diff);
+	}
+
+	sqfs_drop(in);
+	return EXIT_SUCCESS;
+}