ff_init_vlc_from_lengths() can be used to offload the computation
of the codes; it also allows to omit the check whether the codes
are already properly ordered (they are).
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
---
libavcodec/mjpegdec.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 147dd819e5..2a226f63d4 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -50,18 +50,14 @@
#include "bytestream.h"
-static void build_huffman_codes(uint8_t *huff_size, uint16_t *huff_code,
- const uint8_t *bits_table)
+static void build_huffman_codes(uint8_t *huff_size, const uint8_t *bits_table)
{
- for (int i = 1, code = 0, k = 0; i <= 16; i++) {
+ for (int i = 1, k = 0; i <= 16; i++) {
int nb = bits_table[i];
for (int j = 0; j < nb;j++) {
huff_size[k] = i;
- huff_code[k] = code;
- code++;
k++;
}
- code <<= 1;
}
}
@@ -70,13 +66,12 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table,
int is_ac)
{
uint8_t huff_size[256];
- uint16_t huff_code[256];
uint16_t huff_sym[256];
int i;
av_assert0(nb_codes <= 256);
- build_huffman_codes(huff_size, huff_code, bits_table);
+ build_huffman_codes(huff_size, bits_table);
for (i = 0; i < nb_codes; i++) {
huff_sym[i] = val_table[i] + 16 * is_ac;
@@ -85,8 +80,8 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table,
huff_sym[i] = 16 * 256;
}
- return ff_init_vlc_sparse(vlc, 9, nb_codes, huff_size, 1, 1,
- huff_code, 2, 2, huff_sym, 2, 2, 0);
+ return ff_init_vlc_from_lengths(vlc, 9, nb_codes, huff_size, 1,
+ huff_sym, 2, 2, 0, 0);
}
static int init_default_huffman_tables(MJpegDecodeContext *s)
--
2.25.1
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