From a067d449558ac4ff69b53c7e09fdd6396d6f7c0c Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sun, 30 Aug 2020 14:06:11 +0200 Subject: [PATCH] avcodec/roqvideodec: Move transient GetByteContext to the stack 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. Reviewed-by: Paul B Mahol Signed-off-by: Andreas Rheinhardt --- 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;