fp_toradix[_n]: revise and split up
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Steffen Jaeckel
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c485c8d62f
commit
e4f8c04da6
@ -9,77 +9,6 @@
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*/
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#include <tfm.h>
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/**
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* a: pointer to fp_int representing the input number
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* str: output buffer
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* radix: number of character to use for encoding of the number
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* maxlen: maximum number of the buffer that can be used
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*
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* The radix value can be in the range 2 to 64. This function converts number
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* a into a string str. This function writes at most size bytes (including the
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* terminating null byte to str. It behaves like snprintf(3) in regard to this.
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*
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* Return: If invalid parameter are detected a negative value is returned. On
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* success the function returns the number of bytes that would be written if
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* the function had enough space. Thus a return value of maxlen or more means
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* that the function was not able store all characters and the output is
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* incomplete.
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*/
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int fp_toradix_n(fp_int *a, char *str, int radix, unsigned int maxlen)
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{
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int digs;
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fp_int t;
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fp_digit d;
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char *_s = str;
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unsigned int wrote;
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/* check range of the radix */
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if (radix < 2 || radix > 64)
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return -1;
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/* quick check for zero */
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if (fp_iszero(a) == 1) {
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if (maxlen >= 2)
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*str++ = '0';
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if (maxlen >= 1)
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*str = '\0';
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return 1;
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}
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wrote = 0;
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fp_init_copy(&t, a);
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/* if it is negative output a - */
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if (t.sign == FP_NEG) {
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++_s;
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wrote++;
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if (wrote < maxlen)
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*str++ = '-';
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t.sign = FP_ZPOS;
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}
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digs = 0;
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while (fp_iszero (&t) == FP_NO) {
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fp_div_d (&t, (fp_digit) radix, &t, &d);
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wrote++;
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if (wrote < maxlen)
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*str++ = fp_s_rmap[d];
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++digs;
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}
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/* reverse the digits of the string. In this case _s points
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* to the first digit [exluding the sign] of the number]
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*/
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if (wrote < maxlen)
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fp_reverse ((unsigned char *)_s, digs);
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/* append a NULL so the string is properly terminated */
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if (maxlen >= 1)
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*str = '\0';
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return wrote;
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}
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/**
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* a: pointer to fp_int representing the input number
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* str: output buffer
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@ -94,10 +23,9 @@ int fp_toradix_n(fp_int *a, char *str, int radix, unsigned int maxlen)
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*/
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int fp_toradix(fp_int *a, char *str, int radix)
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{
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int ret;
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ret = fp_toradix_n(a, str, radix, UINT_MAX);
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if (ret < 0)
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return FP_VAL;
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return FP_OKAY;
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return fp_toradix_n(a, str, radix, INT_MAX);
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}
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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85
src/bin/fp_toradix_n.c
Normal file
85
src/bin/fp_toradix_n.c
Normal file
@ -0,0 +1,85 @@
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/* TomsFastMath, a fast ISO C bignum library.
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*
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* This project is meant to fill in where LibTomMath
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* falls short. That is speed ;-)
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*
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* This project is public domain and free for all purposes.
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*
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* Tom St Denis, tomstdenis@gmail.com
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*/
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#include <tfm.h>
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/**
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* a: pointer to fp_int representing the input number
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* str: output buffer
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* radix: number of character to use for encoding of the number
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* maxlen: maximum number of the buffer that can be used
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*
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* The radix value can be in the range 2 to 64. This function converts number
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* a into a string str. This function writes at most size bytes (including the
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* terminating null byte to str. It behaves like snprintf(3) in regard to this.
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*
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* Return: If invalid parameter are detected a negative value is returned. On
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* success the function returns the number of bytes that would be written if
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* the function had enough space. Thus a return value of maxlen or more means
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* that the function was not able store all characters and the output is
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* incomplete.
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*/
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int fp_toradix_n(fp_int *a, char *str, int radix, int maxlen)
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{
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int digs;
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fp_int t;
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fp_digit d;
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char *_s = str;
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/* check range of the radix */
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if (maxlen < 2 || radix < 2 || radix > 64)
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return FP_VAL;
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/* quick check for zero */
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if (fp_iszero(a) == FP_YES) {
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*str++ = '0';
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*str = '\0';
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return FP_OKAY;
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}
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fp_init_copy(&t, a);
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/* if it is negative output a - */
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if (t.sign == FP_NEG) {
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/* we have to reverse our digits later... but not the - sign!! */
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++_s;
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/* store the flag and mark the number as positive */
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*str++ = '-';
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t.sign = FP_ZPOS;
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/* subtract a char */
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--maxlen;
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}
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digs = 0;
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while (fp_iszero (&t) == FP_NO) {
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if (--maxlen < 1) {
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/* no more room */
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break;
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}
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fp_div_d(&t, (fp_digit) radix, &t, &d);
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*str++ = fp_s_rmap[d];
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++digs;
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}
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/* reverse the digits of the string. In this case _s points
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* to the first digit [exluding the sign] of the number]
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*/
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fp_reverse((unsigned char *) _s, digs);
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/* append a NULL so the string is properly terminated */
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*str = '\0';
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return FP_OKAY;
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}
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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@ -465,7 +465,7 @@ int fp_read_radix(fp_int *a, char *str, int radix);
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int fp_radix_size(fp_int *a, int radix, int *size);
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int fp_toradix(fp_int *a, char *str, int radix);
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int fp_toradix_n(fp_int * a, char *str, int radix, unsigned int maxlen);
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int fp_toradix_n(fp_int * a, char *str, int radix, int maxlen);
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/* VARIOUS LOW LEVEL STUFFS */
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