[PATCH 1/7] filetype: add file_detect_compression_type()

[Sascha Hauer]

Add file_detect_compression_type() and use that in the uncompression
code which is only interested if the file is one of the supported
compression formats.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 common/filetype.c  | 48 ++++++++++++++++++++++++++++++++----------------
 include/filetype.h |  1 +
 lib/uncompress.c   |  4 ++--
 3 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/common/filetype.c b/common/filetype.c
index 73ea17e19b..9916b63b80 100644
--- a/common/filetype.c
+++ b/common/filetype.c
@@ -261,6 +261,34 @@ static bool is_dos_exe(const u8 *buf8)
 
 #define CH_TOC_section_name     0x14
 
+enum filetype file_detect_compression_type(const void *_buf, size_t bufsize)
+{
+	const u32 *buf = _buf;
+	const u8 *buf8 = _buf;
+
+	if (bufsize < 16)
+		return filetype_unknown;
+
+	if (buf8[0] == 0x89 && buf8[1] == 0x4c && buf8[2] == 0x5a &&
+			buf8[3] == 0x4f)
+		return filetype_lzo_compressed;
+	if (buf8[0] == 0x02 && buf8[1] == 0x21 && buf8[2] == 0x4c &&
+			buf8[3] == 0x18)
+		return filetype_lz4_compressed;
+	if (buf8[0] == 0x1f && buf8[1] == 0x8b && buf8[2] == 0x08)
+		return filetype_gzip;
+	if (buf8[0] == 'B' && buf8[1] == 'Z' && buf8[2] == 'h' &&
+			buf8[3] > '0' && buf8[3] <= '9')
+                return filetype_bzip2;
+	if (buf8[0] == 0xfd && buf8[1] == 0x37 && buf8[2] == 0x7a &&
+			buf8[3] == 0x58 && buf8[4] == 0x5a && buf8[5] == 0x00)
+		return filetype_xz_compressed;
+	if (le32_to_cpu(buf[0]) == le32_to_cpu(ZSTD_MAGICNUMBER))
+		return filetype_zstd_compressed;
+
+	return filetype_unknown;
+}
+
 enum filetype file_detect_type(const void *_buf, size_t bufsize)
 {
 	const u32 *buf = _buf;
@@ -278,17 +306,15 @@ enum filetype file_detect_type(const void *_buf, size_t bufsize)
 	if (buf[0] == ENVFS_32(ENVFS_MAGIC))
 		return filetype_barebox_env;
 
+	type = file_detect_compression_type(_buf, bufsize);
+	if (type != filetype_unknown)
+		return type;
+
 	if (bufsize < 32)
 		return filetype_unknown;
 
 	if (strncmp(buf8, "BM", 2) == 0)
 		return filetype_bmp;
-	if (buf8[0] == 0x89 && buf8[1] == 0x4c && buf8[2] == 0x5a &&
-			buf8[3] == 0x4f)
-		return filetype_lzo_compressed;
-	if (buf8[0] == 0x02 && buf8[1] == 0x21 && buf8[2] == 0x4c &&
-			buf8[3] == 0x18)
-		return filetype_lz4_compressed;
 	if (buf[0] == be32_to_cpu(0x27051956))
 		return filetype_uimage;
 	if (buf[0] == 0x23494255)
@@ -297,14 +323,6 @@ enum filetype file_detect_type(const void *_buf, size_t bufsize)
 		return filetype_ubifs;
 	if (buf[0] == 0x20031985)
 		return filetype_jffs2;
-	if (buf8[0] == 0x1f && buf8[1] == 0x8b && buf8[2] == 0x08)
-		return filetype_gzip;
-	if (buf8[0] == 'B' && buf8[1] == 'Z' && buf8[2] == 'h' &&
-			buf8[3] > '0' && buf8[3] <= '9')
-                return filetype_bzip2;
-	if (buf8[0] == 0xfd && buf8[1] == 0x37 && buf8[2] == 0x7a &&
-			buf8[3] == 0x58 && buf8[4] == 0x5a && buf8[5] == 0x00)
-		return filetype_xz_compressed;
 	if (buf8[0] == 'h' && buf8[1] == 's' && buf8[2] == 'q' &&
 			buf8[3] == 's')
 		return filetype_squashfs;
@@ -325,8 +343,6 @@ enum filetype file_detect_type(const void *_buf, size_t bufsize)
 		return filetype_rockchip_rkns_image;
 	if (le32_to_cpu(buf[0]) == le32_to_cpu(0xaa640001))
 		return filetype_fip;
-	if (le32_to_cpu(buf[0]) == le32_to_cpu(ZSTD_MAGICNUMBER))
-		return filetype_zstd_compressed;
 
 	if ((buf8[0] == 0x5a || buf8[0] == 0x69 || buf8[0] == 0x78 ||
 	     buf8[0] == 0x8b || buf8[0] == 0x9c) &&
diff --git a/include/filetype.h b/include/filetype.h
index c24d061e8f..b8c0105bf2 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -74,6 +74,7 @@ struct cdev;
 const char *file_type_to_string(enum filetype f);
 const char *file_type_to_short_string(enum filetype f);
 enum filetype file_detect_partition_table(const void *_buf, size_t bufsize);
+enum filetype file_detect_compression_type(const void *_buf, size_t bufsize);
 enum filetype file_detect_type(const void *_buf, size_t bufsize);
 int file_name_detect_type(const char *filename, enum filetype *type);
 int file_name_detect_type_offset(const char *filename, loff_t pos, enum filetype *type);
diff --git a/lib/uncompress.c b/lib/uncompress.c
index 0aaeb066b6..c284bcc6ba 100644
--- a/lib/uncompress.c
+++ b/lib/uncompress.c
@@ -79,7 +79,7 @@ int uncompress(unsigned char *inbuf, long len,
 	char *err;
 
 	if (inbuf) {
-		ft = file_detect_type(inbuf, len);
+		ft = file_detect_compression_type(inbuf, len);
 		uncompress_buf = NULL;
 		uncompress_size = 0;
 	} else {
@@ -94,7 +94,7 @@ int uncompress(unsigned char *inbuf, long len,
 		if (ret < 0)
 			goto err;
 
-		ft = file_detect_type(uncompress_buf, 32);
+		ft = file_detect_compression_type(uncompress_buf, 32);
 	}
 
 	pr_debug("Filetype detected: %s\n", file_type_to_string(ft));

-- 
2.39.5