Skip to content

Prevent use of unaligned uint16_t pointers #145

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
daviesrob wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Prevent use of unaligned uint16_t pointers #145

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
44 changes: 20 additions & 24 deletions htscodecs/rANS_static32x16pr.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,6 @@ unsigned char *rans_compress_O0_32x16(unsigned char *in,
} else {
// Branchless version optimises poorly with gcc unless we have
// AVX2 capability, so have a custom rewrite of it.
uint16_t* ptr16 = (uint16_t *)ptr;
for (i=(in_size &~(NX-1)); likely(i>0); i-=NX) {
// Unrolled copy of below, because gcc doesn't optimise this
// well in the original form.
Expand Down Expand Up @@ -197,15 +196,15 @@ unsigned char *rans_compress_O0_32x16(unsigned char *in,
int c1 = rp[3-1] > sy[1]->x_max;

#ifdef HTSCODECS_LITTLE_ENDIAN
ptr16[-1] = rp[3-0]; ptr16 -= c0;
ptr16[-1] = rp[3-1]; ptr16 -= c1;
memcpy(&ptr[-2], &rp[3-0], 2); ptr -= c0 * 2;
memcpy(&ptr[-2], &rp[3-1], 2); ptr -= c1 * 2;
#else
((uint8_t *)&ptr16[-1])[0] = rp[3-0];
((uint8_t *)&ptr16[-1])[1] = rp[3-0]>>8;
ptr16 -= c0;
((uint8_t *)&ptr16[-1])[0] = rp[3-1];
((uint8_t *)&ptr16[-1])[1] = rp[3-1]>>8;
ptr16 -= c1;
ptr[-2] = rp[3-0];
ptr[-1] = rp[3-0]>>8;
ptr -= c0 * 2;
ptr[-2] = rp[3-1];
ptr[-1] = rp[3-1]>>8;
ptr -= c1 * 2;
#endif

rp[3-0] = c0 ? rp[3-0]>>16 : rp[3-0];
Expand All @@ -217,15 +216,15 @@ unsigned char *rans_compress_O0_32x16(unsigned char *in,
int c2 = rp[3-2] > sy[2]->x_max;
int c3 = rp[3-3] > sy[3]->x_max;
#ifdef HTSCODECS_LITTLE_ENDIAN
ptr16[-1] = rp[3-2]; ptr16 -= c2;
ptr16[-1] = rp[3-3]; ptr16 -= c3;
memcpy(&ptr[-2], &rp[3-2], 2); ptr -= c2 * 2;
memcpy(&ptr[-2], &rp[3-3], 2); ptr -= c3 * 2;
#else
((uint8_t *)&ptr16[-1])[0] = rp[3-2];
((uint8_t *)&ptr16[-1])[1] = rp[3-2]>>8;
ptr16 -= c2;
((uint8_t *)&ptr16[-1])[0] = rp[3-3];
((uint8_t *)&ptr16[-1])[1] = rp[3-3]>>8;
ptr16 -= c3;
ptr[-2] = rp[3-2];
ptr[-1] = rp[3-2]>>8;
ptr -= c2 * 2;
ptr[-2] = rp[3-3];
ptr[-1] = rp[3-3]>>8;
ptr -= c3 * 2;
#endif
rp[3-2] = c2 ? rp[3-2]>>16 : rp[3-2];
rp[3-3] = c3 ? rp[3-3]>>16 : rp[3-3];
Expand All @@ -239,7 +238,6 @@ unsigned char *rans_compress_O0_32x16(unsigned char *in,
}
if (z < -1) abort();
}
ptr = (uint8_t *)ptr16;
}
for (z = NX-1; z >= 0; z--)
RansEncFlush(&ransN[z], &ptr);
Expand Down Expand Up @@ -476,7 +474,6 @@ unsigned char *rans_compress_O1_32x16(unsigned char *in,
i32[i] = &in[iN[i]];

for (; likely(i32[0] >= in); ) {
uint16_t *ptr16 = (uint16_t *)ptr;
for (z = NX-1; z >= 0; z-=4) {
RansEncSymbol *sy[4];
int k;
Expand All @@ -490,12 +487,12 @@ unsigned char *rans_compress_O1_32x16(unsigned char *in,
for (k = 0; k < 4; k++) {
int c = ransN[z-k] > sy[k]->x_max;
#ifdef HTSCODECS_LITTLE_ENDIAN
ptr16[-1] = ransN[z-k];
memcpy(&ptr[-2], &ransN[z-k], 2);
#else
((uint8_t *)&ptr16[-1])[0] = ransN[z-k];
((uint8_t *)&ptr16[-1])[1] = ransN[z-k]>>8;
ptr16[-2] = ransN[z-k];
ptr16[-1] = ransN[z-k]>>8;
#endif
ptr16 -= c;
ptr -= c * 2;
//ransN[z-k] >>= c<<4;
ransN[z-k] = c ? ransN[z-k]>>16 : ransN[z-k];
}
Expand All @@ -506,7 +503,6 @@ unsigned char *rans_compress_O1_32x16(unsigned char *in,
ransN[z-k] += sy[k]->bias + q*sy[k]->cmpl_freq;
}
}
ptr = (uint8_t *)ptr16;
}

for (z = NX-1; z>=0; z--)
Expand Down
Loading