[FFmpeg-devel] [PATCH 1/2] avcodec/roqvideodec: Move transient GetByteContext to the stack
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Sun Aug 30 15:39:23 EEST 2020
This avoids keeping potentially dangling pointers in the context,
beautifies the code (by replacing "&ri->gb" by gb for every access to
the GetByteContext) and also highlights the GetByteContext's short-lived
nature better.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
libavcodec/roqvideo.h | 1 -
libavcodec/roqvideodec.c | 61 ++++++++++++++++++++--------------------
2 files changed, 31 insertions(+), 31 deletions(-)
diff --git a/libavcodec/roqvideo.h b/libavcodec/roqvideo.h
index 3da6eaa991..f47b2c8e6f 100644
--- a/libavcodec/roqvideo.h
+++ b/libavcodec/roqvideo.h
@@ -52,7 +52,6 @@ typedef struct RoqContext {
roq_cell cb2x2[256];
roq_qcell cb4x4[256];
- GetByteContext gb;
int width, height;
/* Encoder only data */
diff --git a/libavcodec/roqvideodec.c b/libavcodec/roqvideodec.c
index dd045ed5eb..93c6e9ddf3 100644
--- a/libavcodec/roqvideodec.c
+++ b/libavcodec/roqvideodec.c
@@ -33,7 +33,7 @@
#include "internal.h"
#include "roqvideo.h"
-static void roqvideo_decode_frame(RoqContext *ri)
+static void roqvideo_decode_frame(RoqContext *ri, GetByteContext *gb)
{
unsigned int chunk_id = 0, chunk_arg = 0;
unsigned long chunk_size = 0;
@@ -43,10 +43,10 @@ static void roqvideo_decode_frame(RoqContext *ri)
roq_qcell *qcell;
int64_t chunk_start;
- while (bytestream2_get_bytes_left(&ri->gb) >= 8) {
- chunk_id = bytestream2_get_le16(&ri->gb);
- chunk_size = bytestream2_get_le32(&ri->gb);
- chunk_arg = bytestream2_get_le16(&ri->gb);
+ while (bytestream2_get_bytes_left(gb) >= 8) {
+ chunk_id = bytestream2_get_le16(gb);
+ chunk_size = bytestream2_get_le32(gb);
+ chunk_arg = bytestream2_get_le16(gb);
if(chunk_id == RoQ_QUAD_VQ)
break;
@@ -56,36 +56,36 @@ static void roqvideo_decode_frame(RoqContext *ri)
if((nv2 = chunk_arg & 0xff) == 0 && nv1 * 6 < chunk_size)
nv2 = 256;
for(i = 0; i < nv1; i++) {
- ri->cb2x2[i].y[0] = bytestream2_get_byte(&ri->gb);
- ri->cb2x2[i].y[1] = bytestream2_get_byte(&ri->gb);
- ri->cb2x2[i].y[2] = bytestream2_get_byte(&ri->gb);
- ri->cb2x2[i].y[3] = bytestream2_get_byte(&ri->gb);
- ri->cb2x2[i].u = bytestream2_get_byte(&ri->gb);
- ri->cb2x2[i].v = bytestream2_get_byte(&ri->gb);
+ ri->cb2x2[i].y[0] = bytestream2_get_byte(gb);
+ ri->cb2x2[i].y[1] = bytestream2_get_byte(gb);
+ ri->cb2x2[i].y[2] = bytestream2_get_byte(gb);
+ ri->cb2x2[i].y[3] = bytestream2_get_byte(gb);
+ ri->cb2x2[i].u = bytestream2_get_byte(gb);
+ ri->cb2x2[i].v = bytestream2_get_byte(gb);
}
for(i = 0; i < nv2; i++)
for(j = 0; j < 4; j++)
- ri->cb4x4[i].idx[j] = bytestream2_get_byte(&ri->gb);
+ ri->cb4x4[i].idx[j] = bytestream2_get_byte(gb);
}
}
- chunk_start = bytestream2_tell(&ri->gb);
+ chunk_start = bytestream2_tell(gb);
xpos = ypos = 0;
- if (chunk_size > bytestream2_get_bytes_left(&ri->gb)) {
+ if (chunk_size > bytestream2_get_bytes_left(gb)) {
av_log(ri->avctx, AV_LOG_ERROR, "Chunk does not fit in input buffer\n");
- chunk_size = bytestream2_get_bytes_left(&ri->gb);
+ chunk_size = bytestream2_get_bytes_left(gb);
}
- while (bytestream2_tell(&ri->gb) < chunk_start + chunk_size) {
+ while (bytestream2_tell(gb) < chunk_start + chunk_size) {
for (yp = ypos; yp < ypos + 16; yp += 8)
for (xp = xpos; xp < xpos + 16; xp += 8) {
- if (bytestream2_tell(&ri->gb) >= chunk_start + chunk_size) {
+ if (bytestream2_tell(gb) >= chunk_start + chunk_size) {
av_log(ri->avctx, AV_LOG_VERBOSE, "Chunk is too short\n");
return;
}
if (vqflg_pos < 0) {
- vqflg = bytestream2_get_le16(&ri->gb);
+ vqflg = bytestream2_get_le16(gb);
vqflg_pos = 7;
}
vqid = (vqflg >> (vqflg_pos * 2)) & 0x3;
@@ -96,14 +96,14 @@ static void roqvideo_decode_frame(RoqContext *ri)
case RoQ_ID_MOT:
break;
case RoQ_ID_FCC: {
- int byte = bytestream2_get_byte(&ri->gb);
+ int byte = bytestream2_get_byte(gb);
mx = 8 - (byte >> 4) - ((signed char) (chunk_arg >> 8));
my = 8 - (byte & 0xf) - ((signed char) chunk_arg);
ff_apply_motion_8x8(ri, xp, yp, mx, my);
break;
}
case RoQ_ID_SLD:
- qcell = ri->cb4x4 + bytestream2_get_byte(&ri->gb);
+ qcell = ri->cb4x4 + bytestream2_get_byte(gb);
ff_apply_vector_4x4(ri, xp, yp, ri->cb2x2 + qcell->idx[0]);
ff_apply_vector_4x4(ri, xp + 4, yp, ri->cb2x2 + qcell->idx[1]);
ff_apply_vector_4x4(ri, xp, yp + 4, ri->cb2x2 + qcell->idx[2]);
@@ -115,12 +115,12 @@ static void roqvideo_decode_frame(RoqContext *ri)
if(k & 0x01) x += 4;
if(k & 0x02) y += 4;
- if (bytestream2_tell(&ri->gb) >= chunk_start + chunk_size) {
+ if (bytestream2_tell(gb) >= chunk_start + chunk_size) {
av_log(ri->avctx, AV_LOG_VERBOSE, "Chunk is too short\n");
return;
}
if (vqflg_pos < 0) {
- vqflg = bytestream2_get_le16(&ri->gb);
+ vqflg = bytestream2_get_le16(gb);
vqflg_pos = 7;
}
vqid = (vqflg >> (vqflg_pos * 2)) & 0x3;
@@ -130,24 +130,24 @@ static void roqvideo_decode_frame(RoqContext *ri)
case RoQ_ID_MOT:
break;
case RoQ_ID_FCC: {
- int byte = bytestream2_get_byte(&ri->gb);
+ int byte = bytestream2_get_byte(gb);
mx = 8 - (byte >> 4) - ((signed char) (chunk_arg >> 8));
my = 8 - (byte & 0xf) - ((signed char) chunk_arg);
ff_apply_motion_4x4(ri, x, y, mx, my);
break;
}
case RoQ_ID_SLD:
- qcell = ri->cb4x4 + bytestream2_get_byte(&ri->gb);
+ qcell = ri->cb4x4 + bytestream2_get_byte(gb);
ff_apply_vector_2x2(ri, x, y, ri->cb2x2 + qcell->idx[0]);
ff_apply_vector_2x2(ri, x + 2, y, ri->cb2x2 + qcell->idx[1]);
ff_apply_vector_2x2(ri, x, y + 2, ri->cb2x2 + qcell->idx[2]);
ff_apply_vector_2x2(ri, x + 2, y + 2, ri->cb2x2 + qcell->idx[3]);
break;
case RoQ_ID_CCC:
- ff_apply_vector_2x2(ri, x, y, ri->cb2x2 + bytestream2_get_byte(&ri->gb));
- ff_apply_vector_2x2(ri, x + 2, y, ri->cb2x2 + bytestream2_get_byte(&ri->gb));
- ff_apply_vector_2x2(ri, x, y + 2, ri->cb2x2 + bytestream2_get_byte(&ri->gb));
- ff_apply_vector_2x2(ri, x + 2, y + 2, ri->cb2x2 + bytestream2_get_byte(&ri->gb));
+ ff_apply_vector_2x2(ri, x, y, ri->cb2x2 + bytestream2_get_byte(gb));
+ ff_apply_vector_2x2(ri, x + 2, y, ri->cb2x2 + bytestream2_get_byte(gb));
+ ff_apply_vector_2x2(ri, x, y + 2, ri->cb2x2 + bytestream2_get_byte(gb));
+ ff_apply_vector_2x2(ri, x + 2, y + 2, ri->cb2x2 + bytestream2_get_byte(gb));
break;
}
}
@@ -201,6 +201,7 @@ static int roq_decode_frame(AVCodecContext *avctx,
int buf_size = avpkt->size;
RoqContext *s = avctx->priv_data;
int copy = !s->current_frame->data[0] && s->last_frame->data[0];
+ GetByteContext gb;
int ret;
if ((ret = ff_reget_buffer(avctx, s->current_frame, 0)) < 0)
@@ -212,8 +213,8 @@ static int roq_decode_frame(AVCodecContext *avctx,
return ret;
}
- bytestream2_init(&s->gb, buf, buf_size);
- roqvideo_decode_frame(s);
+ bytestream2_init(&gb, buf, buf_size);
+ roqvideo_decode_frame(s, &gb);
if ((ret = av_frame_ref(data, s->current_frame)) < 0)
return ret;
--
2.20.1
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