diff options
Diffstat (limited to 'py/mpz.c')
| -rw-r--r-- | py/mpz.c | 32 |
1 files changed, 19 insertions, 13 deletions
@@ -1589,7 +1589,7 @@ bool mpz_as_uint_checked(const mpz_t *i, mp_uint_t *value) { return true; } -void mpz_as_bytes(const mpz_t *z, bool big_endian, size_t len, byte *buf) { +bool mpz_as_bytes(const mpz_t *z, bool big_endian, bool as_signed, size_t len, byte *buf) { byte *b = buf; if (big_endian) { b += len; @@ -1598,6 +1598,8 @@ void mpz_as_bytes(const mpz_t *z, bool big_endian, size_t len, byte *buf) { int bits = 0; mpz_dbl_dig_t d = 0; mpz_dbl_dig_t carry = 1; + size_t olen = len; // bytes in output buffer + bool ok = true; for (size_t zlen = z->len; zlen > 0; --zlen) { bits += DIG_SIZE; d = (d << DIG_SIZE) | *zdig++; @@ -1607,28 +1609,32 @@ void mpz_as_bytes(const mpz_t *z, bool big_endian, size_t len, byte *buf) { val = (~val & 0xff) + carry; carry = val >> 8; } + + if (!olen) { + // Buffer is full, only OK if all remaining bytes are zeroes + ok = ok && ((byte)val == 0); + continue; + } + if (big_endian) { *--b = val; - if (b == buf) { - return; - } } else { *b++ = val; - if (b == buf + len) { - return; - } } + olen--; } } - // fill remainder of buf with zero/sign extension of the integer - if (big_endian) { - len = b - buf; + if (as_signed && olen == 0 && len > 0) { + // If output exhausted then ensure there was enough space for the sign bit + byte most_sig = big_endian ? buf[0] : buf[len - 1]; + ok = ok && (bool)(most_sig & 0x80) == (bool)z->neg; } else { - len = buf + len - b; - buf = b; + // fill remainder of buf with zero/sign extension of the integer + memset(big_endian ? buf : b, z->neg ? 0xff : 0x00, olen); } - memset(buf, z->neg ? 0xff : 0x00, len); + + return ok; } #if MICROPY_PY_BUILTINS_FLOAT |