9 files changed, 275 insertions, 84 deletions

diff --git a/bin/rdsquashfs/src/fill_files.c b/bin/rdsquashfs/src/fill_files.c
index 7087883..b26041a 100644
--- a/bin/rdsquashfs/src/fill_files.c
+++ b/bin/rdsquashfs/src/fill_files.c
@@ -137,6 +137,7 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 {
 	int ret, openflags;
 	sqfs_ostream_t *fp;
+	sqfs_istream_t *in;
 	size_t i;
 
 	openflags = SQFS_FILE_OPEN_OVERWRITE;
@@ -154,8 +155,19 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 		if (!(flags & UNPACK_QUIET))
 			printf("unpacking %s\n", files[i].path);
 
-		ret = sqfs_data_reader_dump(files[i].path, data, files[i].inode,
-					    fp, block_size);
+		ret = sqfs_data_reader_create_stream(data, files[i].inode,
+						     files[i].path, &in);
+		if (ret) {
+			sqfs_perror(files[i].path, NULL, ret);
+			return -1;
+		}
+
+		do {
+			ret = sqfs_istream_splice(in, fp, block_size);
+		} while (ret > 0);
+
+		sqfs_drop(in);
+
 		if (ret == 0)
 			ret = fp->flush(fp);
 
diff --git a/bin/rdsquashfs/src/rdsquashfs.c b/bin/rdsquashfs/src/rdsquashfs.c
index 77dc5ba..9d8f3ba 100644
--- a/bin/rdsquashfs/src/rdsquashfs.c
+++ b/bin/rdsquashfs/src/rdsquashfs.c
@@ -208,11 +208,13 @@ int main(int argc, char **argv)
 		break;
 	case OP_CAT: {
 		sqfs_ostream_t *fp;
+		sqfs_istream_t *in;
 		int ret;
 
-		if (!S_ISREG(n->inode->base.mode)) {
-			fprintf(stderr, "/%s: not a regular file\n",
-				opt.cmdpath);
+		ret = sqfs_data_reader_create_stream(data, n->inode,
+						     opt.cmdpath, &in);
+		if (ret) {
+			sqfs_perror(opt.cmdpath, NULL, ret);
 			goto out;
 		}
 
@@ -222,8 +224,13 @@ int main(int argc, char **argv)
 			goto out;
 		}
 
-		ret = sqfs_data_reader_dump(opt.cmdpath, data, n->inode,
-					    fp, super.block_size);
+		do {
+			ret = sqfs_istream_splice(in, fp, super.block_size);
+			if (ret < 0)
+				sqfs_perror(opt.cmdpath, "splicing data", ret);
+		} while (ret > 0);
+
+		sqfs_drop(in);
 		sqfs_drop(fp);
 		if (ret)
 			goto out;
diff --git a/bin/sqfs2tar/src/write_tree.c b/bin/sqfs2tar/src/write_tree.c
index dc3ac72..ed82173 100644
--- a/bin/sqfs2tar/src/write_tree.c
+++ b/bin/sqfs2tar/src/write_tree.c
@@ -157,13 +157,26 @@ static int write_tree_dfs(const sqfs_tree_node_t *n)
 	}
 
 	if (S_ISREG(sb.st_mode)) {
-		if (sqfs_data_reader_dump(name, data, n->inode, out_file,
-					  super.block_size)) {
+		sqfs_istream_t *in;
+		int ret;
+
+		ret = sqfs_data_reader_create_stream(data, n->inode, name, &in);
+		if (ret) {
+			sqfs_perror(name, NULL, ret);
 			sqfs_free(name);
 			return -1;
 		}
 
-		ret = padd_file(out_file, sb.st_size);
+		do {
+			ret = sqfs_istream_splice(in, out_file,
+						  super.block_size);
+		} while (ret > 0);
+
+		sqfs_drop(in);
+
+		if (ret == 0)
+			ret = padd_file(out_file, sb.st_size);
+
 		if (ret) {
 			sqfs_perror(name, NULL, ret);
 			sqfs_free(name);
diff --git a/bin/sqfsdiff/src/extract.c b/bin/sqfsdiff/src/extract.c
index cbc4381..df74f0f 100644
--- a/bin/sqfsdiff/src/extract.c
+++ b/bin/sqfsdiff/src/extract.c
@@ -11,6 +11,7 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 {
 	char *ptr, *temp;
 	sqfs_ostream_t *fp;
+	sqfs_istream_t *in;
 	int ret;
 
 	temp = alloca(strlen(prefix) + strlen(path) + 2);
@@ -28,12 +29,23 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 		return -1;
 	}
 
-	if (sqfs_data_reader_dump(path, data, inode, fp, block_size)) {
+	ret = sqfs_data_reader_create_stream(data, inode, path, &in);
+	if (ret) {
 		sqfs_drop(fp);
 		return -1;
 	}
 
-	ret = fp->flush(fp);
+	do {
+		ret = sqfs_istream_splice(in, fp, block_size);
+		if (ret < 0)
+			sqfs_perror(path, "splicing data", ret);
+	} while (ret > 0);
+
+	sqfs_drop(in);
+
+	if (ret == 0)
+		ret = fp->flush(fp);
+
 	if (ret) {
 		sqfs_perror(fp->get_filename(fp), NULL, ret);
 		sqfs_drop(fp);
diff --git a/include/common.h b/include/common.h
index 8e24d03..707d46b 100644
--- a/include/common.h
+++ b/include/common.h
@@ -33,10 +33,6 @@ typedef struct sqfs_hard_link_t {
 	char *target;
 } sqfs_hard_link_t;
 
-int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
-			  const sqfs_inode_generic_t *inode,
-			  sqfs_ostream_t *fp, size_t block_size);
-
 int write_data_from_file(const char *filename, sqfs_block_processor_t *data,
 			 sqfs_inode_generic_t **inode,
 			 sqfs_file_t *file, int flags);
diff --git a/include/sqfs/data_reader.h b/include/sqfs/data_reader.h
index 29077b7..dabf5c8 100644
--- a/include/sqfs/data_reader.h
+++ b/include/sqfs/data_reader.h
@@ -145,6 +145,27 @@ SQFS_API sqfs_s32 sqfs_data_reader_read(sqfs_data_reader_t *data,
 					sqfs_u64 offset, void *buffer,
 					sqfs_u32 size);
 
+/**
+ * @brief Create an @ref sqfs_istream_t implementation for a squashfs file
+ *
+ * @memberof sqfs_data_reader_t
+ *
+ * This function creates a simple file stream implementation that internally
+ * reads data from a file in a SquashFS image. The reader is grabbed, the inode
+ * and filename are copied internally and not needed after creation.
+ *
+ * @param data A pointer to a data reader object.
+ * @param inode A pointer to the inode describing the file.
+ * @param filename A file name that the stream should return when asked.
+ * @param out Returns a pointer to a stream on success, NULL on failure.
+ *
+ * @return Zero on success, a negative @ref SQFS_ERROR value on failure.
+ */
+SQFS_API int sqfs_data_reader_create_stream(sqfs_data_reader_t *data,
+					    const sqfs_inode_generic_t *inode,
+					    const char *filename,
+					    sqfs_istream_t **out);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/common/Makemodule.am b/lib/common/Makemodule.am
index 61d87d4..e0cc551 100644
--- a/lib/common/Makemodule.am
+++ b/lib/common/Makemodule.am
@@ -1,7 +1,7 @@
 libcommon_a_SOURCES = include/common.h include/simple_writer.h \
 	include/compress_cli.h \
 	lib/common/src/hardlink.c lib/common/src/print_version.c \
-	lib/common/src/data_reader_dump.c lib/common/src/compress.c \
+	lib/common/src/compress.c \
 	lib/common/src/comp_opt.c lib/common/src/data_writer.c \
 	lib/common/src/parse_size.c lib/common/src/print_size.c \
 	lib/common/src/writer/init.c lib/common/src/writer/cleanup.c \
diff --git a/lib/common/src/data_reader_dump.c b/lib/common/src/data_reader_dump.c
deleted file mode 100644
index 920b2bd..0000000
--- a/lib/common/src/data_reader_dump.c
+++ /dev/null
@@ -1,67 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * data_reader_dump.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "common.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <errno.h>
-
-int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
-			  const sqfs_inode_generic_t *inode,
-			  sqfs_ostream_t *fp, size_t block_size)
-{
-	size_t i, diff, chunk_size;
-	sqfs_u64 filesz;
-	sqfs_u8 *chunk;
-	int err;
-
-	sqfs_inode_get_file_size(inode, &filesz);
-
-	for (i = 0; i < sqfs_inode_get_file_block_count(inode); ++i) {
-		diff = (filesz < block_size) ? filesz : block_size;
-
-		if (SQFS_IS_SPARSE_BLOCK(inode->extra[i])) {
-			err = fp->append(fp, NULL, diff);
-		} else {
-			err = sqfs_data_reader_get_block(data, inode, i,
-							 &chunk_size, &chunk);
-			if (err) {
-				sqfs_perror(name, "reading data block", err);
-				return -1;
-			}
-
-			err = fp->append(fp, chunk, chunk_size);
-			free(chunk);
-		}
-
-		if (err)
-			goto fail_io;
-
-		filesz -= diff;
-	}
-
-	if (filesz > 0) {
-		err = sqfs_data_reader_get_fragment(data, inode,
-						    &chunk_size, &chunk);
-		if (err) {
-			sqfs_perror(name, "reading fragment block", err);
-			return -1;
-		}
-
-		err = fp->append(fp, chunk, chunk_size);
-		free(chunk);
-
-		if (err)
-			goto fail_io;
-	}
-
-	return 0;
-fail_io:
-	sqfs_perror(fp->get_filename(fp), "writing data block", err);
-	return -1;
-}
diff --git a/lib/sqfs/src/data_reader.c b/lib/sqfs/src/data_reader.c
index 3f0cd74..e87259f 100644
--- a/lib/sqfs/src/data_reader.c
+++ b/lib/sqfs/src/data_reader.c
@@ -372,3 +372,200 @@ sqfs_s32 sqfs_data_reader_read(sqfs_data_reader_t *data,
 
 	return total;
 }
+
+/*****************************************************************************/
+
+typedef struct {
+	sqfs_istream_t base;
+
+	sqfs_data_reader_t *rd;
+	const char *filename;
+	const sqfs_u32 *blocks;
+
+	sqfs_u8 *buffer;
+	size_t buf_used;
+	size_t buf_off;
+
+	sqfs_u64 filesz;
+	sqfs_u64 disk_offset;
+
+	sqfs_u32 frag_idx;
+	sqfs_u32 frag_off;
+
+	sqfs_u32 blk_idx;
+	sqfs_u32 blk_count;
+
+	sqfs_u32 inodata[];
+} data_reader_istream_t;
+
+static int dr_stream_get_buffered_data(sqfs_istream_t *base,
+				       const sqfs_u8 **out,
+				       size_t *size, size_t want)
+{
+	data_reader_istream_t *stream = (data_reader_istream_t *)base;
+	sqfs_data_reader_t *rd = stream->rd;
+	int ret;
+	(void)want;
+
+	if (stream->buf_off < stream->buf_used) {
+		*out = stream->buffer + stream->buf_off;
+		*size = stream->buf_used - stream->buf_off;
+		return 0;
+	}
+
+	if (stream->filesz == 0) {
+		ret = 1;
+		goto fail;
+	}
+
+	stream->buf_off = 0;
+	stream->buf_used = rd->block_size;
+	if (stream->filesz < (sqfs_u64)stream->buf_used)
+		stream->buf_used = stream->filesz;
+
+	if (stream->blk_idx < stream->blk_count) {
+		sqfs_u32 blkword = stream->blocks[stream->blk_idx++];
+		sqfs_u32 disksz = SQFS_ON_DISK_BLOCK_SIZE(blkword);
+
+		if (disksz == 0) {
+			memset(stream->buffer, 0, stream->buf_used);
+		} else if (SQFS_IS_BLOCK_COMPRESSED(blkword)) {
+			ret = rd->file->read_at(rd->file, stream->disk_offset,
+						rd->scratch, disksz);
+			if (ret)
+				goto fail;
+
+			ret = rd->cmp->do_block(rd->cmp, rd->scratch, disksz,
+						stream->buffer,
+						stream->buf_used);
+			if (ret <= 0) {
+				ret = ret < 0 ? ret : SQFS_ERROR_OVERFLOW;
+				goto fail;
+			}
+
+			if ((size_t)ret < stream->buf_used) {
+				memset(stream->buffer + ret, 0,
+				       stream->buf_used - ret);
+			}
+		} else {
+			ret = rd->file->read_at(rd->file, stream->disk_offset,
+						stream->buffer, disksz);
+			if (ret)
+				goto fail;
+			if (disksz < stream->buf_used) {
+				memset(stream->buffer + disksz, 0,
+				       stream->buf_used - disksz);
+			}
+		}
+
+		stream->disk_offset += disksz;
+	} else {
+		ret = precache_fragment_block(rd, stream->frag_idx);
+		if (ret)
+			return ret;
+
+		if (rd->frag_blk_size < stream->frag_off ||
+		    (rd->frag_blk_size - stream->frag_off) < stream->buf_used) {
+			ret = SQFS_ERROR_CORRUPTED;
+			goto fail;
+		}
+
+		memcpy(stream->buffer, rd->frag_block + stream->frag_off,
+		       stream->buf_used);
+	}
+
+	stream->filesz -= stream->buf_used;
+	*out = stream->buffer;
+	*size = stream->buf_used;
+	return 0;
+fail:
+	free(stream->buffer);
+	stream->buffer = NULL;
+	stream->buf_used = 0;
+	stream->buf_off = 0;
+	stream->filesz = 0;
+	*out = NULL;
+	*size = 0;
+	return ret;
+}
+
+static void dr_stream_advance_buffer(sqfs_istream_t *base, size_t count)
+{
+	data_reader_istream_t *stream = (data_reader_istream_t *)base;
+	size_t diff = stream->buf_used - stream->buf_off;
+
+	stream->buf_off += (diff < count ? diff : count);
+}
+
+static const char *dr_stream_get_filename(sqfs_istream_t *base)
+{
+	return ((data_reader_istream_t *)base)->filename;
+}
+
+static void dr_stream_destroy(sqfs_object_t *obj)
+{
+	data_reader_istream_t *stream = (data_reader_istream_t *)obj;
+
+	sqfs_drop(stream->rd);
+	free(stream->buffer);
+	free(stream);
+}
+
+int sqfs_data_reader_create_stream(sqfs_data_reader_t *data,
+				   const sqfs_inode_generic_t *inode,
+				   const char *filename, sqfs_istream_t **out)
+{
+	data_reader_istream_t *stream;
+	size_t ino_sz, namelen, sz;
+	sqfs_u64 filesz;
+	char *nameptr;
+	int ret;
+
+	*out = NULL;
+
+	ret = sqfs_inode_get_file_size(inode, &filesz);
+	if (ret != 0)
+		return ret;
+
+	ino_sz = inode->payload_bytes_used;
+	namelen = strlen(filename) + 1;
+
+	if (SZ_ADD_OV(ino_sz, namelen, &sz))
+		return SQFS_ERROR_ALLOC;
+	if (SZ_ADD_OV(sz, sizeof(*stream), &sz))
+		return SQFS_ERROR_ALLOC;
+
+	stream = calloc(1, sz);
+	if (stream == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	stream->buffer = malloc(data->block_size);
+	if (stream->buffer == NULL) {
+		free(stream);
+		return SQFS_ERROR_ALLOC;
+	}
+
+	sqfs_object_init(stream, dr_stream_destroy, NULL);
+
+	memcpy(stream->inodata, inode->extra, ino_sz);
+	stream->blocks = stream->inodata;
+	stream->blk_count = ino_sz / sizeof(stream->blocks[0]);
+	stream->filesz = filesz;
+
+	nameptr = (char *)stream->inodata + ino_sz;
+	memcpy(nameptr, filename, namelen);
+	stream->filename = nameptr;
+
+	sqfs_inode_get_file_block_start(inode, &stream->disk_offset);
+	sqfs_inode_get_frag_location(inode, &stream->frag_idx,
+				     &stream->frag_off);
+	stream->rd = sqfs_grab(data);
+
+	((sqfs_istream_t *)stream)->advance_buffer = dr_stream_advance_buffer;
+	((sqfs_istream_t *)stream)->get_filename = dr_stream_get_filename;
+	((sqfs_istream_t *)stream)->get_buffered_data =
+		dr_stream_get_buffered_data;
+
+	*out = (sqfs_istream_t *)stream;
+	return 0;
+}