libmp - traditional BSD multiple precision integer arithmetic library
Function prototypes are given in the main body of the text.
Applications using this interface must be linked with -l mp (this library) and -l crypto (crypto(3) )
is the traditional BSD multiple precision integer arithmetic library. It has a number of problems, and is unsuitable for use in any programs where reliability is a concern. It is provided here for compatibility only.
These routines perform arithmetic on integers of arbitrary precision
stored using the defined type
Vt MINT .
Pointers to
Vt MINT
are initialized using
itom ();
or
xtom (,);
and must be recycled with
mfree ();
when they are no longer needed.
Routines which store a result in one of their arguments expect that
the latter has also been initialized prior to being passed to it.
The following routines are defined and implemented:
MINT * Ns
itom (short n ;);
MINT * Ns
xtom (const char *s ;);
char * Ns
mtox (const MINT *mp ;);
void
mfree (MINT *mp ;);
itom ();
returns an Vt MINT with the value of Fa n . xtom ();
returns an Vt MINT with the value of Fa s , which is treated to be in hexadecimal. The return values from itom ();
and xtom ();
must be released with mfree ();
when they are no longer needed. mtox ();
returns a null-terminated hexadecimal string having the value of Fa mp ; its return value must be released with free ();
(free(3) ) when it is no longer needed.
void
madd (const MINT *mp1 const MINT *mp2 MINT *rmp ;);
void
msub (const MINT *mp1 const MINT *mp2 MINT *rmp ;);
void
mult (const MINT *mp1 const MINT *mp2 MINT *rmp ;);
madd (,);
msub (,);
and mult ();
store the sum, difference, or product, respectively, of Fa mp1 and Fa mp2 in Fa rmp .
void
mdiv (const MINT *nmp const MINT *dmp MINT *qmp MINT *rmp ;);
void
sdiv (const MINT *nmp short d MINT *qmp short *ro ;);
mdiv ();
computes the quotient and remainder of Fa nmp and Fa dmp and stores the result in Fa qmp and Fa rmp , respectively. sdiv ();
is similar to mdiv ();
except the divisor Fa ( dmp or Fa d ) and remainder Fa ( rmp or Fa ro ) are ordinary integers.
void
pow (const MINT *bmp const MINT *emp const MINT *mmp MINT *rmp ;);
void
rpow (const MINT *bmp short e MINT *rmp ;);
rpow ();
computes the result of Fa bmp raised to the Fa emp Ns th power and reduced modulo Fa mmp ; the result is stored in Fa rmp . pow ();
computes the result of Fa bmp raised to the Fa e Ns th power and stores the result in Fa rmp .
void
min (MINT *mp ;);
void
mout (const MINT *mp ;);
min ();
reads a line from standard input, tries to interpret it as a decimal number, and if successful, stores the result in Fa mp . mout ();
prints the value, in decimal, of Fa mp to standard output (without a trailing newline).
void
gcd (const MINT *mp1 const MINT *mp2 MINT *rmp ;);
gcd ();
computes the greatest common divisor of Fa mp1 and Fa mp2 and stores the result in Fa rmp .
int
mcmp (const MINT *mp1 const MINT *mp2 ;);
Fa mcmp compares the values of Fa mp1 and Fa mp2 and returns 0 if the two values are equal, a value greater than 0 if Fa mp1 is greater than Fa mp2 , and a value less than 0 if Fa mp2 is greater than Fa mp1 .
void
move (const MINT *smp MINT *tmp ;);
move ();
copies the value of Fa smp to Fa tmp (both values must be initialized).
void
msqrt (const MINT *nmp MINT *xmp MINT *rmp ;);
msqrt ();
computes the square root and remainder of Fa nmp and stores them in Fa xmp and Fa rmp , respectively.
Errors are reported via output to standard error and abnormal program termination instead of via return values. The application cannot control this behavior.
It is not clear whether the string returned by
mtox ();
may be written to by the caller.
This implementation allows it, but others may not.
Ideally,
mtox ();
would take a pointer to a buffer to fill in.
It is not clear whether using the same variable as both source and destination in a single invocation is permitted. Some of the calls in this implementation allow this, while others do not.
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