/**
* @file int64.c
*
* @brief Functions for 64-bit integer computations.
*
* 21-jan-1998: David Perkins <dperkins@dsperkins.com>
*/
#include <net-snmp/net-snmp-config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <net-snmp/types.h>
#include <net-snmp/library/int64.h>
#include <net-snmp/library/snmp_assert.h>
#include <net-snmp/library/snmp_debug.h>
#include <net-snmp/library/snmp_logging.h>
#include <net-snmp/net-snmp-features.h>
/**
* Divide an unsigned 64-bit integer by 10.
*
* @param[in] u64 Number to be divided.
* @param[out] pu64Q Quotient.
* @param[out] puR Remainder.
*/
void
divBy10(struct counter64 u64, struct counter64 *pu64Q, unsigned int *puR)
{
unsigned long ulT;
unsigned long ulQ;
unsigned long ulR;
/*
* top 16 bits
*/
ulT = (u64.high >> 16) & 0x0ffff;
ulQ = ulT / 10;
ulR = ulT % 10;
pu64Q->high = ulQ << 16;
/*
* next 16
*/
ulT = (u64.high & 0x0ffff);
ulT += (ulR << 16);
ulQ = ulT / 10;
ulR = ulT % 10;
pu64Q->high = pu64Q->high | ulQ;
/*
* next 16
*/
ulT = ((u64.low >> 16) & 0x0ffff) + (ulR << 16);
ulQ = ulT / 10;
ulR = ulT % 10;
pu64Q->low = ulQ << 16;
/*
* final 16
*/
ulT = (u64.low & 0x0ffff);
ulT += (ulR << 16);
ulQ = ulT / 10;
ulR = ulT % 10;
pu64Q->low = pu64Q->low | ulQ;
*puR = (unsigned int) (ulR);
}
/**
* Multiply an unsigned 64-bit integer by 10.
*
* @param[in] u64 Number to be multiplied.
* @param[out] pu64P Product.
*/
void
multBy10(struct counter64 u64, struct counter64 *pu64P)
{
unsigned long ulT;
unsigned long ulP;
unsigned long ulK;
/*
* lower 16 bits
*/
ulT = u64.low & 0x0ffff;
ulP = ulT * 10;
ulK = ulP >> 16;
pu64P->low = ulP & 0x0ffff;
/*
* next 16
*/
ulT = (u64.low >> 16) & 0x0ffff;
ulP = (ulT * 10) + ulK;
ulK = ulP >> 16;
pu64P->low = (ulP & 0x0ffff) << 16 | pu64P->low;
/*
* next 16 bits
*/
ulT = u64.high & 0x0ffff;
ulP = (ulT * 10) + ulK;
ulK = ulP >> 16;
pu64P->high = ulP & 0x0ffff;
/*
* final 16
*/
ulT = (u64.high >> 16) & 0x0ffff;
ulP = (ulT * 10) + ulK;
ulK = ulP >> 16;
pu64P->high = (ulP & 0x0ffff) << 16 | pu64P->high;
}
/**
* Add an unsigned 16-bit int to an unsigned 64-bit integer.
*
* @param[in,out] pu64 Number to be incremented.
* @param[in] u16 Amount to add.
*
*/
void
incrByU16(struct counter64 *pu64, unsigned int u16)
{
incrByU32(pu64, u16);
}
/**
* Add an unsigned 32-bit int to an unsigned 64-bit integer.
*
* @param[in,out] pu64 Number to be incremented.
* @param[in] u32 Amount to add.
*
*/
void
incrByU32(struct counter64 *pu64, unsigned int u32)
{
uint32_t tmp;
tmp = pu64->low;
pu64->low = (uint32_t)(tmp + u32);
if (pu64->low < tmp)
pu64->high = (uint32_t)(pu64->high + 1);
}
/**
* Subtract two 64-bit numbers.
*
* @param[in] pu64one Number to start from.
* @param[in] pu64two Amount to subtract.
* @param[out] pu64out pu64one - pu64two.
*/
void
u64Subtract(const struct counter64 *pu64one, const struct counter64 *pu64two,
struct counter64 *pu64out)
{
int carry;
carry = pu64one->low < pu64two->low;
pu64out->low = (uint32_t)(pu64one->low - pu64two->low);
pu64out->high = (uint32_t)(pu64one->high - pu64two->high - carry);
}
/**
* Add two 64-bit numbers.
*
* @param[in] pu64one Amount to add.
* @param[in,out] pu64out pu64out += pu64one.
*/
void
u64Incr(struct counter64 *pu64out, const struct counter64 *pu64one)
{
pu64out->high = (uint32_t)(pu64out->high + pu64one->high);
incrByU32(pu64out, pu64one->low);
}
/**
* Add the difference of two 64-bit numbers to a 64-bit counter.
*
* @param[in] pu64one
* @param[in] pu64two
* @param[out] pu64out pu64out += (pu64one - pu64two)
*/
void
u64UpdateCounter(struct counter64 *pu64out, const struct counter64 *pu64one,
const struct counter64 *pu64two)
{
struct counter64 tmp;
u64Subtract(pu64one, pu64two, &tmp);
u64Incr(pu64out, &tmp);
}
netsnmp_feature_child_of(u64copy, netsnmp_unused)
#ifndef NETSNMP_FEATURE_REMOVE_U64COPY
/**
* Copy a 64-bit number.
*
* @param[in] pu64two Number to be copied.
* @param[out] pu64one Where to store the copy - *pu64one = *pu64two.
*/
void
u64Copy(struct counter64 *pu64one, const struct counter64 *pu64two)
{
*pu64one = *pu64two;
}
#endif /* NETSNMP_FEATURE_REMOVE_U64COPY */
/**
* Set an unsigned 64-bit number to zero.
*
* @param[in] pu64 Number to be zeroed.
*/
void
zeroU64(struct counter64 *pu64)
{
pu64->low = 0;
pu64->high = 0;
}
/**
* Check if an unsigned 64-bit number is zero.
*
* @param[in] pu64 Number to be checked.
*/
int
isZeroU64(const struct counter64 *pu64)
{
return pu64->low == 0 && pu64->high == 0;
}
/**
* check the old and new values of a counter64 for 32bit wrapping
*
* @param adjust : set to 1 to auto-increment new_val->high
* if a 32bit wrap is detected.
*
* @param old_val
* @param new_val
*
* @note
* The old and new values must be be from within a time period
* which would only allow the 32bit portion of the counter to
* wrap once. i.e. if the 32bit portion of the counter could
* wrap every 60 seconds, the old and new values should be compared
* at least every 59 seconds (though I'd recommend at least every
* 50 seconds to allow for timer inaccuracies).
*
* @retval 64 : 64bit wrap
* @retval 32 : 32bit wrap
* @retval 0 : did not wrap
* @retval -1 : bad parameter
* @retval -2 : unexpected high value (changed by more than 1)
*/
int
netsnmp_c64_check_for_32bit_wrap(struct counter64 *old_val,
struct counter64 *new_val,
int adjust)
{
if( (NULL == old_val) || (NULL == new_val) )
return -1;
DEBUGMSGTL(("9:c64:check_wrap", "check wrap 0x%0lx.0x%0lx 0x%0lx.0x%0lx\n",
old_val->high, old_val->low, new_val->high, new_val->low));
/*
* check for wraps
*/
if ((new_val->low >= old_val->low) &&
(new_val->high == old_val->high)) {
DEBUGMSGTL(("9:c64:check_wrap", "no wrap\n"));
return 0;
}
/*
* low wrapped. did high change?
*/
if (new_val->high == old_val->high) {
DEBUGMSGTL(("c64:check_wrap", "32 bit wrap\n"));
if (adjust)
new_val->high = (uint32_t)(new_val->high + 1);
return 32;
}
else if (new_val->high == (uint32_t)(old_val->high + 1)) {
DEBUGMSGTL(("c64:check_wrap", "64 bit wrap\n"));
return 64;
}
return -2;
}
/**
* update a 64 bit value with the difference between two (possibly) 32 bit vals
*
* @param prev_val : the 64 bit current counter
* @param old_prev_val : the (possibly 32 bit) previous value
* @param new_val : the (possible 32bit) new value
* @param need_wrap_check: pointer to integer indicating if wrap check is needed
* flag may be cleared if 64 bit counter is detected
*
* @note
* The old_prev_val and new_val values must be be from within a time
* period which would only allow the 32bit portion of the counter to
* wrap once. i.e. if the 32bit portion of the counter could
* wrap every 60 seconds, the old and new values should be compared
* at least every 59 seconds (though I'd recommend at least every
* 50 seconds to allow for timer inaccuracies).
*
* Suggested use:
*
* static needwrapcheck = 1;
* static counter64 current, prev_val, new_val;
*
* your_functions_to_update_new_value(&new_val);
* if (0 == needwrapcheck)
* memcpy(current, new_val, sizeof(new_val));
* else {
* netsnmp_c64_check32_and_update(¤t,&new,&prev,&needwrapcheck);
* memcpy(prev_val, new_val, sizeof(new_val));
* }
*
*
* @retval 0 : success
* @retval -1 : error checking for 32 bit wrap
* @retval -2 : look like we have 64 bit values, but sums aren't consistent
*/
int
netsnmp_c64_check32_and_update(struct counter64 *prev_val,
struct counter64 *new_val,
struct counter64 *old_prev_val,
int *need_wrap_check)
{
int rc;
/*
* counters are 32bit or unknown (which we'll treat as 32bit).
* update the prev values with the difference between the
* new stats and the prev old_stats:
* prev->stats += (new->stats - prev->old_stats)
*/
if ((NULL == need_wrap_check) || (0 != *need_wrap_check)) {
rc = netsnmp_c64_check_for_32bit_wrap(old_prev_val,new_val, 1);
if (rc < 0) {
DEBUGMSGTL(("c64","32 bit check failed\n"));
return -1;
}
}
else
rc = 0;
/*
* update previous values
*/
(void) u64UpdateCounter(prev_val, new_val, old_prev_val);
/*
* if wrap check was 32 bit, undo adjust, now that prev is updated
*/
if (32 == rc) {
/*
* check wrap incremented high, so reset it. (Because having
* high set for a 32 bit counter will confuse us in the next update).
*/
if (1 != new_val->high)
DEBUGMSGTL(("c64", "error expanding to 64 bits: new_val->high != 1"));
new_val->high = 0;
}
else if (64 == rc) {
/*
* if we really have 64 bit counters, the summing we've been
* doing for prev values should be equal to the new values.
*/
if ((prev_val->low != new_val->low) ||
(prev_val->high != new_val->high)) {
DEBUGMSGTL(("c64", "looks like a 64bit wrap, but prev!=new\n"));
return -2;
}
else if (NULL != need_wrap_check)
*need_wrap_check = 0;
}
return 0;
}
/** Convert an unsigned 64-bit number to ASCII. */
void
printU64(char *buf, /* char [I64CHARSZ+1]; */
const struct counter64 *pu64)
{
struct counter64 u64a;
struct counter64 u64b;
char aRes[I64CHARSZ + 1];
unsigned int u;
int j;
u64a = *pu64;
aRes[I64CHARSZ] = 0;
for (j = 0; j < I64CHARSZ; j++) {
divBy10(u64a, &u64b, &u);
aRes[(I64CHARSZ - 1) - j] = (char) ('0' + u);
u64a = u64b;
if (isZeroU64(&u64a))
break;
}
strcpy(buf, &aRes[(I64CHARSZ - 1) - j]);
}
/** Convert a signed 64-bit number to ASCII. */
void
printI64(char *buf, /* char [I64CHARSZ+1]; */
const struct counter64 *pu64)
{
struct counter64 u64a;
if (pu64->high & 0x80000000) {
u64a.high = (uint32_t) ~pu64->high;
u64a.low = (uint32_t) ~pu64->low;
incrByU32(&u64a, 1); /* bit invert and incr by 1 to print 2s complement */
buf[0] = '-';
printU64(buf + 1, &u64a);
} else {
printU64(buf, pu64);
}
}
/** Convert a signed 64-bit integer from ASCII to struct counter64. */
int
read64(struct counter64 *i64, const char *str)
{
struct counter64 i64p;
unsigned int u;
int sign = 0;
int ok = 0;
zeroU64(i64);
if (*str == '-') {
sign = 1;
str++;
}
while (*str && isdigit((unsigned char)(*str))) {
ok = 1;
u = *str - '0';
multBy10(*i64, &i64p);
*i64 = i64p;
incrByU16(i64, u);
str++;
}
if (sign) {
i64->high = (uint32_t) ~i64->high;
i64->low = (uint32_t) ~i64->low;
incrByU16(i64, 1);
}
return ok;
}