/**
* file2key – A simple command that generates a key from a file and a passphrase
*
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "keccak.h"
#define lane_t int_fast64_t
#define ulane_t uint_fast64_t
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wsign-conversion"
/**
* Round contants
*/
static const lane_t RC[] = {
0x0000000000000001LL, 0x0000000000008082LL, 0x800000000000808ALL, 0x8000000080008000LL,
0x000000000000808BLL, 0x0000000080000001LL, 0x8000000080008081LL, 0x8000000000008009LL,
0x000000000000008ALL, 0x0000000000000088LL, 0x0000000080008009LL, 0x000000008000000ALL,
0x000000008000808BLL, 0x800000000000008BLL, 0x8000000000008089LL, 0x8000000000008003LL,
0x8000000000008002LL, 0x8000000000000080LL, 0x000000000000800ALL, 0x800000008000000ALL,
0x8000000080008081LL, 0x8000000000008080LL, 0x0000000080000001LL, 0x8000000080008008LL};
# pragma GCC diagnostic pop
/**
* Keccak-f round temporary
*/
static lane_t B[25];
/**
* Keccak-f round temporary
*/
static lane_t C[5];
/**
* The current state
*/
static lane_t* S = NULL;
/**
* Left over water to fill the sponge with at next update
*/
static int8_t* M = NULL;
/**
* Pointer for {@link #M}
*/
static long mptr = 0;
/**
* Size of {@link #M}
*/
static long mlen = 0;
/**
* Hash output buffer
*/
static int8_t* output = NULL;
/**
* Copy an array segment into an array in start to end order
*
* @param src The source array
* @param soff The source array offset
* @param dest The destination array
* @param doff The destination array offset
* @param length The number of elements to copy
*/
static inline void arraycopy(const int8_t* restrict src, long soff, int8_t* restrict dest, long doff, long length)
{
long i;
src += soff;
dest += doff;
#define __(X) dest[X] = src[X]
#define __0 *dest = *src
#define __1 __(0x01)
#define __2 __(0x02); __(0x03)
#define __3 __(0x04); __(0x05); __(0x06); __(0x07)
#define __4 __(0x08); __(0x09); __(0x0A); __(0x0B); __(0x0C); __(0x0D); __(0x0E); __(0x0F)
#define __5 __(0x10); __(0x11); __(0x12); __(0x13); __(0x14); __(0x15); __(0x16); __(0x17); __(0x18); __(0x19); __(0x1A); __(0x1B); __(0x1C); __(0x1D); __(0x1E); __(0x1F)
#define __6 __(0x20); __(0x21); __(0x22); __(0x23); __(0x24); __(0x25); __(0x26); __(0x27); __(0x28); __(0x29); __(0x2A); __(0x2B); __(0x2C); __(0x2D); __(0x2E); __(0x2F); \
__(0x30); __(0x31); __(0x32); __(0x33); __(0x34); __(0x35); __(0x36); __(0x37); __(0x38); __(0x39); __(0x3A); __(0x3B); __(0x3C); __(0x3D); __(0x3E); __(0x3F)
#define __7 __(0x40); __(0x41); __(0x42); __(0x43); __(0x44); __(0x45); __(0x46); __(0x47); __(0x48); __(0x49); __(0x4A); __(0x4B); __(0x4C); __(0x4D); __(0x4E); __(0x4F); \
__(0x50); __(0x51); __(0x52); __(0x53); __(0x54); __(0x55); __(0x56); __(0x57); __(0x58); __(0x59); __(0x5A); __(0x5B); __(0x5C); __(0x5D); __(0x5E); __(0x5F); \
__(0x60); __(0x61); __(0x62); __(0x63); __(0x64); __(0x65); __(0x66); __(0x67); __(0x68); __(0x69); __(0x6A); __(0x6B); __(0x6C); __(0x6D); __(0x6E); __(0x6F); \
__(0x70); __(0x71); __(0x72); __(0x73); __(0x74); __(0x75); __(0x76); __(0x77); __(0x78); __(0x79); __(0x7A); __(0x7B); __(0x7C); __(0x7D); __(0x7E); __(0x7F)
#define __8 __(0x80); __(0x81); __(0x82); __(0x83); __(0x84); __(0x85); __(0x86); __(0x87); __(0x88); __(0x89); __(0x8A); __(0x8B); __(0x8C); __(0x8D); __(0x8E); __(0x8F); \
__(0x90); __(0x91); __(0x92); __(0x93); __(0x94); __(0x95); __(0x96); __(0x97); __(0x98); __(0x99); __(0x9A); __(0x9B); __(0x9C); __(0x9D); __(0x9E); __(0x9F); \
__(0xA0); __(0xA1); __(0xA2); __(0xA3); __(0xA4); __(0xA5); __(0xA6); __(0xA7); __(0xA8); __(0xA9); __(0xAA); __(0xAB); __(0xAC); __(0xAD); __(0xAE); __(0xAF); \
__(0xB0); __(0xB1); __(0xB2); __(0xB3); __(0xB4); __(0xB5); __(0xB6); __(0xB7); __(0xB8); __(0xB9); __(0xBA); __(0xBB); __(0xBC); __(0xBD); __(0xBE); __(0xBF); \
__(0xC0); __(0xC1); __(0xC2); __(0xC3); __(0xC4); __(0xC5); __(0xC6); __(0xC7); __(0xC8); __(0xC9); __(0xCA); __(0xCB); __(0xCC); __(0xCD); __(0xCE); __(0xCF); \
__(0xD0); __(0xD1); __(0xD2); __(0xD3); __(0xD4); __(0xD5); __(0xD6); __(0xD7); __(0xD8); __(0xD9); __(0xDA); __(0xDB); __(0xDC); __(0xDD); __(0xDE); __(0xDF); \
__(0xE0); __(0xE1); __(0xE2); __(0xE3); __(0xE4); __(0xE5); __(0xE6); __(0xE7); __(0xE8); __(0xE9); __(0xEA); __(0xEB); __(0xEC); __(0xED); __(0xEE); __(0xEF); \
__(0xF0); __(0xF1); __(0xF2); __(0xF3); __(0xF4); __(0xF5); __(0xF6); __(0xF7); __(0xF8); __(0xF9); __(0xFA); __(0xFB); __(0xFC); __(0xFD); __(0xFE); __(0xFF)
if ((length & 15))
{
if ((length & 1)) { __0; src += 1; dest += 1; }
if ((length & 2)) { __0; __1; src += 2; dest += 2; }
if ((length & 4)) { __0; __1; __2; src += 4; dest += 4; }
if ((length & 8)) { __0; __1; __2; __3; src += 8; dest += 8; }
}
if ((length & 240))
{
if ((length & 16)) { __0; __1; __2; __3; __4; src += 16; dest += 16; }
if ((length & 32)) { __0; __1; __2; __3; __4; __5; src += 32; dest += 32; }
if ((length & 64)) { __0; __1; __2; __3; __4; __5; __6; src += 64; dest += 64; }
if ((length & 128)) { __0; __1; __2; __3; __4; __5; __6; __7; src += 128; dest += 128; }
}
length &= ~255;
for (i = 0; i < length; i += 256)
{
__0; __1; __2; __3; __4; __5; __6; __7; __8; src += 256; dest += 256;
}
#undef __8
#undef __7
#undef __6
#undef __5
#undef __4
#undef __3
#undef __2
#undef __1
#undef __0
#undef __
}
/**
* Copy an array segment into an array in end to start order
*
* @param src The source array
* @param soff The source array offset
* @param dest The destination array
* @param doff The destination array offset
* @param length The number of elements to copy
*/
static inline void revarraycopy(const int8_t* restrict src, long soff, int8_t* restrict dest, long doff, long length)
{
long copyi;
for (copyi = length - 1; copyi >= 0; copyi--)
dest[copyi + doff] = src[copyi + soff];
}
/**
* Rotate a 64-bit word
*
* @param X:lane_t The value to rotate
* @param N:long Rotation steps, may not be 0
* @return :lane_t The value rotated
*/
#define rotate(X, N) ((lane_t)((ulane_t)(X) >> (64 - (N))) + ((X) << (N)))
/**
* Perform one round of computation
*
* @param A The current state
* @param rc Round constant
*/
static void keccakFRound(lane_t* restrict A, lane_t rc)
{
lane_t da, db, dc, dd, de;
/* θ step (step 1 and 2 of 3) */
#define __C(I, J0, J1, J2, J3, J4) C[I] = (A[J0] ^ A[J1]) ^ (A[J2] ^ A[J3]) ^ A[J4]
__C(0, 0, 1, 2, 3, 4);
__C(1, 5, 6, 7, 8, 9);
__C(2, 10, 11, 12, 13, 14);
__C(3, 15, 16, 17, 18, 19);
__C(4, 20, 21, 22, 23, 24);
#undef __C
da = C[4] ^ rotate(C[1], 1);
dd = C[2] ^ rotate(C[4], 1);
db = C[0] ^ rotate(C[2], 1);
de = C[3] ^ rotate(C[0], 1);
dc = C[1] ^ rotate(C[3], 1);
/* ρ and π steps, with last two part of θ */
#define __B(Bi, Ai, Dv, R) B[Bi] = rotate(A[Ai] ^ Dv, R)
B[0] = A[0] ^ da; __B( 1, 15, dd, 28); __B( 2, 5, db, 1); __B( 3, 20, de, 27); __B( 4, 10, dc, 62);
__B( 5, 6, db, 44); __B( 6, 21, de, 20); __B( 7, 11, dc, 6); __B( 8, 1, da, 36); __B( 9, 16, dd, 55);
__B(10, 12, dc, 43); __B(11, 2, da, 3); __B(12, 17, dd, 25); __B(13, 7, db, 10); __B(14, 22, de, 39);
__B(15, 18, dd, 21); __B(16, 8, db, 45); __B(17, 23, de, 8); __B(18, 13, dc, 15); __B(19, 3, da, 41);
__B(20, 24, de, 14); __B(21, 14, dc, 61); __B(22, 4, da, 18); __B(23, 19, dd, 56); __B(24, 9, db, 2);
#undef __B
/* ξ step */
#define __A(X, X5, X10) A[X] = B[X] ^ ((~(B[X5])) & B[X10])
__A( 0, 5, 10); __A( 1, 6, 11); __A( 2, 7, 12); __A( 3, 8, 13); __A( 4, 9, 14);
__A( 5, 10, 15); __A( 6, 11, 16); __A( 7, 12, 17); __A( 8, 13, 18); __A( 9, 14, 19);
__A(10, 15, 20); __A(11, 16, 21); __A(12, 17, 22); __A(13, 18, 23); __A(14, 19, 24);
__A(15, 20, 0); __A(16, 21, 1); __A(17, 22, 2); __A(18, 23, 3); __A(19, 24, 4);
__A(20, 0, 5); __A(21, 1, 6); __A(22, 2, 7); __A(23, 3, 8); __A(24, 4, 9);
#undef __A
/* ι step */
A[0] ^= rc;
}
/**
* Perform Keccak-f function
*
* @param A The current state
*/
static void keccakF(lane_t* restrict A)
{
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wsign-conversion"
keccakFRound(A, 0x0000000000000001LL);
keccakFRound(A, 0x0000000000008082LL);
keccakFRound(A, 0x800000000000808ALL);
keccakFRound(A, 0x8000000080008000LL);
keccakFRound(A, 0x000000000000808BLL);
keccakFRound(A, 0x0000000080000001LL);
keccakFRound(A, 0x8000000080008081LL);
keccakFRound(A, 0x8000000000008009LL);
keccakFRound(A, 0x000000000000008ALL);
keccakFRound(A, 0x0000000000000088LL);
keccakFRound(A, 0x0000000080008009LL);
keccakFRound(A, 0x000000008000000ALL);
keccakFRound(A, 0x000000008000808BLL);
keccakFRound(A, 0x800000000000008BLL);
keccakFRound(A, 0x8000000000008089LL);
keccakFRound(A, 0x8000000000008003LL);
keccakFRound(A, 0x8000000000008002LL);
keccakFRound(A, 0x8000000000000080LL);
keccakFRound(A, 0x000000000000800ALL);
keccakFRound(A, 0x800000008000000ALL);
keccakFRound(A, 0x8000000080008081LL);
keccakFRound(A, 0x8000000000008080LL);
keccakFRound(A, 0x0000000080000001LL);
keccakFRound(A, 0x8000000080008008LL);
# pragma GCC diagnostic pop
}
/**
* Convert a chunk of byte:s to a 64-bit word
*
* @param message The message
* @param msglen The length of the message
* @param off The offset in the message
* @return Lane
*/
static inline lane_t toLane(const int8_t* restrict message, long msglen, long off)
{
long n = msglen < 128 ? msglen : 128;
return ((off + 7 < n) ? ((lane_t)(message[off + 7] & 255) << 56) : 0L) |
((off + 6 < n) ? ((lane_t)(message[off + 6] & 255) << 48) : 0L) |
((off + 5 < n) ? ((lane_t)(message[off + 5] & 255) << 40) : 0L) |
((off + 4 < n) ? ((lane_t)(message[off + 4] & 255) << 32) : 0L) |
((off + 3 < n) ? ((lane_t)(message[off + 3] & 255) << 24) : 0L) |
((off + 2 < n) ? ((lane_t)(message[off + 2] & 255) << 16) : 0L) |
((off + 1 < n) ? ((lane_t)(message[off + 1] & 255) << 8) : 0L) |
((off < n) ? ((lane_t)(message[off ] & 255) ) : 0L);
}
/**
* pad 10*1
*
* @param msg The message to pad
* @param len The length of the message
* @param outlen The length of the padded message (out parameter)
* @return The message padded
*/
static inline int8_t* pad10star1(const int8_t* restrict msg, long len, long* restrict outlen)
{
int8_t* message;
long nrf = (len <<= 3) >> 3;
long nbrf = len & 7;
long ll = len & 1023;
long i;
int8_t b = (int8_t)(nbrf == 0 ? 1 : ((msg[nrf] >> (8 - nbrf)) | (1 << nbrf)));
if ((1016 <= ll) && (ll <= 1022))
{
message = malloc((size_t)(len = nrf + 1) * sizeof(int8_t));
message[nrf] = (int8_t)(b ^ 128);
}
else
{
int8_t* m;
long n;
len = (nrf + 1) << 3;
len = ((len - (len & 1023) + 1016) >> 3) + 1;
message = malloc((size_t)len * sizeof(int8_t));
message[nrf] = b;
n = len - nrf - 1;
m = message + nrf + 1;
#define __(X) m[X] = 0
#define __0 *m = 0
#define __1 __(0x01)
#define __2 __(0x02); __(0x03)
#define __3 __(0x04); __(0x05); __(0x06); __(0x07)
#define __4 __(0x08); __(0x09); __(0x0A); __(0x0B); __(0x0C); __(0x0D); __(0x0E); __(0x0F)
#define __5 __(0x10); __(0x11); __(0x12); __(0x13); __(0x14); __(0x15); __(0x16); __(0x17); __(0x18); __(0x19); __(0x1A); __(0x1B); __(0x1C); __(0x1D); __(0x1E); __(0x1F)
#define __6 __(0x20); __(0x21); __(0x22); __(0x23); __(0x24); __(0x25); __(0x26); __(0x27); __(0x28); __(0x29); __(0x2A); __(0x2B); __(0x2C); __(0x2D); __(0x2E); __(0x2F); \
__(0x30); __(0x31); __(0x32); __(0x33); __(0x34); __(0x35); __(0x36); __(0x37); __(0x38); __(0x39); __(0x3A); __(0x3B); __(0x3C); __(0x3D); __(0x3E); __(0x3F)
#define __7 __(0x40); __(0x41); __(0x42); __(0x43); __(0x44); __(0x45); __(0x46); __(0x47); __(0x48); __(0x49); __(0x4A); __(0x4B); __(0x4C); __(0x4D); __(0x4E); __(0x4F); \
__(0x50); __(0x51); __(0x52); __(0x53); __(0x54); __(0x55); __(0x56); __(0x57); __(0x58); __(0x59); __(0x5A); __(0x5B); __(0x5C); __(0x5D); __(0x5E); __(0x5F); \
__(0x60); __(0x61); __(0x62); __(0x63); __(0x64); __(0x65); __(0x66); __(0x67); __(0x68); __(0x69); __(0x6A); __(0x6B); __(0x6C); __(0x6D); __(0x6E); __(0x6F); \
__(0x70); __(0x71); __(0x72); __(0x73); __(0x74); __(0x75); __(0x76); __(0x77); __(0x78); __(0x79); __(0x7A); __(0x7B); __(0x7C); __(0x7D); __(0x7E); __(0x7F)
#define __8 __(0x80); __(0x81); __(0x82); __(0x83); __(0x84); __(0x85); __(0x86); __(0x87); __(0x88); __(0x89); __(0x8A); __(0x8B); __(0x8C); __(0x8D); __(0x8E); __(0x8F); \
__(0x90); __(0x91); __(0x92); __(0x93); __(0x94); __(0x95); __(0x96); __(0x97); __(0x98); __(0x99); __(0x9A); __(0x9B); __(0x9C); __(0x9D); __(0x9E); __(0x9F); \
__(0xA0); __(0xA1); __(0xA2); __(0xA3); __(0xA4); __(0xA5); __(0xA6); __(0xA7); __(0xA8); __(0xA9); __(0xAA); __(0xAB); __(0xAC); __(0xAD); __(0xAE); __(0xAF); \
__(0xB0); __(0xB1); __(0xB2); __(0xB3); __(0xB4); __(0xB5); __(0xB6); __(0xB7); __(0xB8); __(0xB9); __(0xBA); __(0xBB); __(0xBC); __(0xBD); __(0xBE); __(0xBF); \
__(0xC0); __(0xC1); __(0xC2); __(0xC3); __(0xC4); __(0xC5); __(0xC6); __(0xC7); __(0xC8); __(0xC9); __(0xCA); __(0xCB); __(0xCC); __(0xCD); __(0xCE); __(0xCF); \
__(0xD0); __(0xD1); __(0xD2); __(0xD3); __(0xD4); __(0xD5); __(0xD6); __(0xD7); __(0xD8); __(0xD9); __(0xDA); __(0xDB); __(0xDC); __(0xDD); __(0xDE); __(0xDF); \
__(0xE0); __(0xE1); __(0xE2); __(0xE3); __(0xE4); __(0xE5); __(0xE6); __(0xE7); __(0xE8); __(0xE9); __(0xEA); __(0xEB); __(0xEC); __(0xED); __(0xEE); __(0xEF); \
__(0xF0); __(0xF1); __(0xF2); __(0xF3); __(0xF4); __(0xF5); __(0xF6); __(0xF7); __(0xF8); __(0xF9); __(0xFA); __(0xFB); __(0xFC); __(0xFD); __(0xFE); __(0xFF)
if ((n & 15))
{
if ((n & 1)) { __0; m += 1; }
if ((n & 2)) { __0; __1; m += 2; }
if ((n & 4)) { __0; __1; __2; m += 4; }
if ((n & 8)) { __0; __1; __2; __3; m += 8; }
}
if ((n & 240))
{
if ((n & 16)) { __0; __1; __2; __3; __4; m += 16; }
if ((n & 32)) { __0; __1; __2; __3; __4; __5; m += 32; }
if ((n & 64)) { __0; __1; __2; __3; __4; __5; __6; m += 64; }
if ((n & 128)) { __0; __1; __2; __3; __4; __5; __6; __7; m += 128; }
}
n &= ~255;
for (i = 0; i < n; i += 256)
{
__0; __1; __2; __3; __4; __5; __6; __7; __8; m += 256;
}
#undef __8
#undef __7
#undef __6
#undef __5
#undef __4
#undef __3
#undef __2
#undef __1
#undef __0
#undef __
message[len - 1] = -128;
}
arraycopy(msg, 0, message, 0, nrf);
*outlen = len;
return message;
}
/**
* Initialise Keccak[r=1024, c=576, n=576] sponge
*/
void initialise(void)
{
long i;
output = malloc(72 * sizeof(int8_t));
S = malloc(25 * sizeof(lane_t));
M = malloc((size_t)(mlen = 409600) * sizeof(int8_t));
mptr = 0;
for (i = 0; i < 25; i++)
*(S + i) = 0;
}
/**
* Dispose of the Keccak sponge
*/
void dispose(void)
{
free(output);
free(S);
free(M);
}
/**
* Absorb the more of the message message to the Keccak sponge
*
* @param msg The partial message
* @param msglen The length of the partial message
*/
void update(const int8_t* restrict msg, long msglen)
{
long i, len, nnn;
int8_t* message;
int8_t* _msg;
if (mptr + msglen > mlen)
{
int8_t* buf = malloc((size_t)(mlen = (mlen + msglen) << 1) * sizeof(int8_t));
arraycopy(M, 0, buf, 0, mptr);
free(M);
M = buf;
}
arraycopy(msg, 0, M, mptr, msglen);
len = mptr += msglen;
len -= len % 204800;
_msg = message = malloc((size_t)len * sizeof(int8_t));
arraycopy(M, 0, message, 0, len);
mptr -= len;
revarraycopy(M, nnn = len, M, 0, mptr);
/* Absorbing phase */
for (i = 0; i < nnn; i += 128)
{
#define __S(Si, OFF) S[Si] ^= toLane(message, len, OFF)
__S( 0, 0); __S( 5, 8); __S(10, 16); __S(15, 24); __S(20, 32);
__S( 1, 40); __S( 6, 48); __S(11, 56); __S(16, 64); __S(21, 72);
__S( 2, 80); __S( 7, 88); __S(12, 96); __S(17, 104); __S(22, 112);
__S( 3, 120); __S( 8, 128); __S(13, 136); __S(18, 144); __S(23, 152);
__S( 4, 160); __S( 9, 168); __S(14, 176); __S(19, 184); __S(24, 192);
#undef __S
keccakF(S);
message += 128;
len -= 128;
}
free(_msg);
}
/**
* Absorb the last part of the message and squeeze the Keccak sponge
*
* @param msg The rest of the message, may be {@code NULL}
* @param msglen The length of the partial message
* @return The hash sum
*/
int8_t* digest(const int8_t* restrict msg, long msglen)
{
int8_t* message;
int8_t* rc;
int8_t* _msg;
long len, i, j, ptr = 0, nnn;
if ((msg == NULL) || (msglen == 0))
message = pad10star1(M, mptr, &len);
else
{
if (mptr + msglen > mlen)
{
int8_t* buf = malloc((size_t)(mlen += msglen) * sizeof(int8_t));
arraycopy(M, 0, buf, 0, mptr);
free(M);
M = buf;
}
arraycopy(msg, 0, M, mptr, msglen);
message = pad10star1(M, mptr + msglen, &len);
}
free(M);
M = NULL;
nnn = len;
_msg = message;
/* Absorbing phase */
for (i = 0; i < nnn; i += 128)
{
#define __S(Si, OFF) S[Si] ^= toLane(message, len, OFF)
__S( 0, 0); __S( 5, 8); __S(10, 16); __S(15, 24); __S(20, 32);
__S( 1, 40); __S( 6, 48); __S(11, 56); __S(16, 64); __S(21, 72);
__S( 2, 80); __S( 7, 88); __S(12, 96); __S(17, 104); __S(22, 112);
__S( 3, 120); __S( 8, 128); __S(13, 136); __S(18, 144); __S(23, 152);
__S( 4, 160); __S( 9, 168); __S(14, 176); __S(19, 184); __S(24, 192);
#undef __S
keccakF(S);
message += 128;
len -= 128;
}
free(_msg);
/* Squeezing phase */
for (i = 0; i < 9; i++)
{
lane_t v = S[(i % 5) * 5 + i / 5];
for (j = 0; j < 8; j++)
{
output[ptr++] = (int8_t)v;
v >>= 8;
}
}
return output;
}
/**
* Squeeze out another digest
*
* @return The hash sum
*/
int8_t* squeeze(void)
{
long i, j, ptr;
keccakF(S); /* Last squeeze did not do a ending squeeze */
ptr = 0;
for (i = 0; i < 9; i++)
{
lane_t v = S[(i % 5) * 5 + i / 5];
for (j = 0; j < 8; j++)
{
*(output + ptr++) = (int8_t)v;
v >>= 8;
}
}
return output;
}
