From f5ee6093d4bfb9026c61e29e5182c1227158a33d Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Tue, 21 May 2019 00:52:45 +0200
Subject: Add options for lz4 compressor
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
lib/comp/lz4.c | 35 +++++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)
(limited to 'lib')
diff --git a/lib/comp/lz4.c b/lib/comp/lz4.c
index 63ed528..e0bba9c 100644
--- a/lib/comp/lz4.c
+++ b/lib/comp/lz4.c
@@ -11,6 +11,7 @@
typedef struct {
compressor_t base;
+ bool high_compression;
} lz4_compressor_t;
typedef struct {
@@ -19,14 +20,15 @@ typedef struct {
} lz4_options;
#define LZ4LEGACY 1
+#define LZ4_FLAG_HC 0x01
static int lz4_write_options(compressor_t *base, int fd)
{
+ lz4_compressor_t *lz4 = (lz4_compressor_t *)base;
lz4_options opt = {
.version = htole32(LZ4LEGACY),
- .flags = htole32(0),
+ .flags = htole32(lz4->high_compression ? LZ4_FLAG_HC : 0),
};
- (void)base;
return generic_write_options(fd, &opt, sizeof(opt));
}
@@ -53,10 +55,16 @@ static int lz4_read_options(compressor_t *base, int fd)
static ssize_t lz4_comp_block(compressor_t *base, const uint8_t *in,
size_t size, uint8_t *out, size_t outsize)
{
+ lz4_compressor_t *lz4 = (lz4_compressor_t *)base;
int ret;
- (void)base;
- ret = LZ4_compress_default((void *)in, (void *)out, size, outsize);
+ if (lz4->high_compression) {
+ ret = LZ4_compress_HC((void *)in, (void *)out,
+ size, outsize, LZ4HC_CLEVEL_MAX);
+ } else {
+ ret = LZ4_compress_default((void *)in, (void *)out,
+ size, outsize);
+ }
if (ret < 0) {
fputs("internal error in lz4 compressor\n", stderr);
@@ -99,6 +107,19 @@ compressor_t *create_lz4_compressor(bool compress, size_t block_size,
return NULL;
}
+ lz4->high_compression = false;
+
+ if (options != NULL) {
+ if (strcmp(options, "hc") == 0) {
+ lz4->high_compression = true;
+ } else {
+ fputs("Unsupported extra options for lz4 "
+ "compressor.\n", stderr);
+ free(lz4);
+ return NULL;
+ }
+ }
+
base->destroy = lz4_destroy;
base->do_block = compress ? lz4_comp_block : lz4_uncomp_block;
base->write_options = lz4_write_options;
@@ -108,4 +129,10 @@ compressor_t *create_lz4_compressor(bool compress, size_t block_size,
void compressor_lz4_print_help(void)
{
+ fputs("Available options for lz4 compressor:\n"
+ "\n"
+ " hc If present, use slower but better compressing\n"
+ " variant of lz4.\n"
+ "\n",
+ stdout);
}
--
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