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Diffstat (limited to 'lib/lzo/lzo1x_compress.c')
-rw-r--r--lib/lzo/lzo1x_compress.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/lib/lzo/lzo1x_compress.c b/lib/lzo/lzo1x_compress.c
index 4525fb094844..a8ede77afe0d 100644
--- a/lib/lzo/lzo1x_compress.c
+++ b/lib/lzo/lzo1x_compress.c
@@ -291,13 +291,14 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
{
const unsigned char *ip = in;
unsigned char *op = out;
+ unsigned char *data_start;
size_t l = in_len;
size_t t = 0;
signed char state_offset = -2;
unsigned int m4_max_offset;
- // LZO v0 will never write 17 as first byte,
- // so this is used to version the bitstream
+ // LZO v0 will never write 17 as first byte (except for zero-length
+ // input), so this is used to version the bitstream
if (bitstream_version > 0) {
*op++ = 17;
*op++ = bitstream_version;
@@ -306,6 +307,8 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
m4_max_offset = M4_MAX_OFFSET_V0;
}
+ data_start = op;
+
while (l > 20) {
size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
uintptr_t ll_end = (uintptr_t) ip + ll;
@@ -324,7 +327,7 @@ int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
if (t > 0) {
const unsigned char *ii = in + in_len - t;
- if (op == out && t <= 238) {
+ if (op == data_start && t <= 238) {
*op++ = (17 + t);
} else if (t <= 3) {
op[state_offset] |= t;