mirror of
https://github.com/levinsv/pgadmin3.git
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147 lines
3.2 KiB
C++
147 lines
3.2 KiB
C++
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/*
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* M_APM - mapm_pow.c
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*
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* Copyright (C) 2000 - 2007 Michael C. Ring
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*
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* Permission to use, copy, and distribute this software and its
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* documentation for any purpose with or without fee is hereby granted,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation.
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*
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* Permission to modify the software is granted. Permission to distribute
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* the modified code is granted. Modifications are to be distributed by
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* using the file 'license.txt' as a template to modify the file header.
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* 'license.txt' is available in the official MAPM distribution.
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*
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* This software is provided "as is" without express or implied warranty.
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*/
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/*
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*
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* This file contains the POW function.
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*
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*/
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#include "pgAdmin3.h"
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#include "pgscript/utilities/mapm-lib/m_apm_lc.h"
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static M_APM M_last_xx_input;
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static M_APM M_last_xx_log;
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static int M_last_log_digits;
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static int M_size_flag = 0;
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/****************************************************************************/
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void M_free_all_pow()
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{
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if (M_size_flag != 0)
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{
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m_apm_free(M_last_xx_input);
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m_apm_free(M_last_xx_log);
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M_size_flag = 0;
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}
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}
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/****************************************************************************/
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/*
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Calculate the POW function by calling EXP :
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Y A
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X = e where A = Y * log(X)
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*/
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void m_apm_pow(M_APM rr, int places, M_APM xx, M_APM yy)
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{
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int iflag, pflag;
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char sbuf[64];
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M_APM tmp8, tmp9;
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/* if yy == 0, return 1 */
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if (yy->m_apm_sign == 0)
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{
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m_apm_copy(rr, MM_One);
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return;
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}
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/* if xx == 0, return 0 */
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if (xx->m_apm_sign == 0)
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{
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M_set_to_zero(rr);
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return;
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}
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if (M_size_flag == 0) /* init locals on first call */
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{
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M_size_flag = M_get_sizeof_int();
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M_last_log_digits = 0;
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M_last_xx_input = m_apm_init();
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M_last_xx_log = m_apm_init();
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}
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/*
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* if 'yy' is a small enough integer, call the more
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* efficient _integer_pow function.
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*/
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if (m_apm_is_integer(yy))
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{
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iflag = FALSE;
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if (M_size_flag == 2) /* 16 bit compilers */
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{
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if (yy->m_apm_exponent <= 4)
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iflag = TRUE;
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}
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else /* >= 32 bit compilers */
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{
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if (yy->m_apm_exponent <= 7)
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iflag = TRUE;
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}
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if (iflag)
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{
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m_apm_to_integer_string(sbuf, yy);
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m_apm_integer_pow(rr, places, xx, atoi(sbuf));
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return;
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}
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}
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tmp8 = M_get_stack_var();
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tmp9 = M_get_stack_var();
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/*
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* If parameter 'X' is the same this call as it
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* was the previous call, re-use the saved log
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* calculation from last time.
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*/
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pflag = FALSE;
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if (M_last_log_digits >= places)
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{
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if (m_apm_compare(xx, M_last_xx_input) == 0)
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pflag = TRUE;
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}
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if (pflag)
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{
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m_apm_round(tmp9, (places + 8), M_last_xx_log);
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}
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else
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{
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m_apm_log(tmp9, (places + 8), xx);
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M_last_log_digits = places + 2;
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/* save the 'X' input value and the log calculation */
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m_apm_copy(M_last_xx_input, xx);
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m_apm_copy(M_last_xx_log, tmp9);
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}
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m_apm_multiply(tmp8, tmp9, yy);
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m_apm_exp(rr, places, tmp8);
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M_restore_stack(2); /* restore the 2 locals we used here */
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}
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/****************************************************************************/
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