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Made crypt/decrypt faster.

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This commit is contained in:
Bram Moolenaar
2010-06-01 23:37:39 +02:00
parent 8cd213c09a
commit 04c9bafa71
6 changed files with 89 additions and 69 deletions
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96
src/misc2.c
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@@ -3724,39 +3724,81 @@ make_crc_tab()
#define CRC32(c, b) (crc_32_tab[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
static ulg keys[3]; /* keys defining the pseudo-random sequence */
/*
* Return the next byte in the pseudo-random sequence
* Return the next byte in the pseudo-random sequence.
*/
int
decrypt_byte()
{
ush temp;
if (use_crypt_method > 0)
return bf_ranbyte();
temp = (ush)keys[2] | 2;
return (int)(((unsigned)(temp * (temp ^ 1)) >> 8) & 0xff);
#define DECRYPT_BYTE_ZIP(t) { \
ush temp; \
\
temp = (ush)keys[2] | 2; \
t = (int)(((unsigned)(temp * (temp ^ 1)) >> 8) & 0xff); \
}
/*
* Update the encryption keys with the next byte of plain text
* Update the encryption keys with the next byte of plain text.
*/
#define UPDATE_KEYS_ZIP(c) { \
keys[0] = CRC32(keys[0], (c)); \
keys[1] += keys[0] & 0xff; \
keys[1] = keys[1] * 134775813L + 1; \
keys[2] = CRC32(keys[2], (int)(keys[1] >> 24)); \
}
/*
* Encrypt "from[len]" into "to[len]".
* "from" and "to" can be equal to encrypt in place.
*/
void
update_keys(c)
int c; /* byte of plain text */
crypt_encode(from, len, to)
char_u *from;
size_t len;
char_u *to;
{
if (use_crypt_method > 0)
bf_ofb_update(c);
size_t i;
int ztemp, t;
if (use_crypt_method == 0)
for (i = 0; i < len; ++i)
{
ztemp = from[i];
DECRYPT_BYTE_ZIP(t);
UPDATE_KEYS_ZIP(ztemp);
to[i] = t ^ ztemp;
}
else
{
keys[0] = CRC32(keys[0], c);
keys[1] += keys[0] & 0xff;
keys[1] = keys[1] * 134775813L + 1;
keys[2] = CRC32(keys[2], (int)(keys[1] >> 24));
}
for (i = 0; i < len; ++i)
{
ztemp = from[i];
t = bf_ranbyte();
bf_ofb_update(ztemp);
to[i] = t ^ ztemp;
}
}
/*
* Decrypt "ptr[len]" in place.
*/
void
crypt_decode(ptr, len)
char_u *ptr;
long len;
{
char_u *p;
if (use_crypt_method == 0)
for (p = ptr; p < ptr + len; ++p)
{
ush temp;
temp = (ush)keys[2] | 2;
temp = (int)(((unsigned)(temp * (temp ^ 1)) >> 8) & 0xff);
UPDATE_KEYS_ZIP(*p ^= temp);
}
else
for (p = ptr; p < ptr + len; ++p)
bf_ofb_update(*p ^= bf_ranbyte());
}
/*
@@ -3774,8 +3816,14 @@ crypt_init_keys(passwd)
keys[0] = 305419896L;
keys[1] = 591751049L;
keys[2] = 878082192L;
while (*passwd != '\0')
update_keys((int)*passwd++);
if (use_crypt_method == 0)
while (*passwd != '\0')
{
UPDATE_KEYS_ZIP((int)*passwd++);
}
else
while (*passwd != '\0')
bf_ofb_update((int)*passwd++);
}
}