570 lines
15 KiB
C
570 lines
15 KiB
C
/*
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* evaluate the dc language, from a FILE* or a string
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*
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* Copyright (C) 1994 Free Software Foundation, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you can either send email to this
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* program's author (see below) or write to: The Free Software Foundation,
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* Inc.; 675 Mass Ave. Cambridge, MA 02139, USA.
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*/
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/* This is the only module which knows about the dc input language */
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#include "config.h"
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#include <stdio.h>
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#include <string.h>
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#include "dc.h"
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#include "dc-proto.h"
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typedef enum {
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DC_OKAY, /* no further intervention needed for this command */
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DC_EATONE, /* caller needs to eat the lookahead char */
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DC_QUIT, /* quit out of unwind_depth levels of evaluation */
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/* with the following return values, the caller does not have to
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* fret about rescan_stdin's value
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*/
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DC_INT, /* caller needs to parse a dc_num from input stream */
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DC_STR, /* caller needs to parse a dc_str from input stream */
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DC_SYSTEM, /* caller needs to run a system() on next input line */
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DC_COMMENT, /* caller needs to skip to the next input line */
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DC_EOF_ERROR /* unexpected end of input; abort current eval */
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} dc_status;
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static int dc_ibase=10; /* input base, 2 <= dc_ibase <= DC_IBASE_MAX */
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static int dc_obase=10; /* output base, 2 <= dc_obase */
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static int dc_scale=0; /* scale (see user documentaton) */
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/* forward reference */
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static dc_status dc_evalstr DC_PROTO((dc_data));
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/* for Quitting evaluations */
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static int unwind_depth=0;
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/* if true, active Quit will not exit program */
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static dc_boolean unwind_noexit=DC_FALSE;
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/* if true, stdin has been mucked with, dc_evalfile() needs to resyncronize */
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static dc_boolean rescan_stdin=DC_FALSE;
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/* input_fil and input_str are passed as arguments to dc_getnum */
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/* used by the input_* functions: */
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static FILE *input_fil_fp;
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static const char *input_str_string;
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/* Since we have a need for two characters of pushback, and
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* ungetc() only guarantees one, we place the second pushback here
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*/
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static int input_pushback;
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/* passed as an argument to dc_getnum */
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static int
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input_fil DC_DECLVOID()
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{
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if (input_pushback != EOF){
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int c = input_pushback;
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input_pushback = EOF;
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return c;
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}
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return getc(input_fil_fp);
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}
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/* passed as an argument to dc_getnum */
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static int
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input_str DC_DECLVOID()
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{
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if (!*input_str_string)
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return EOF;
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return *input_str_string++;
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}
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/* takes a string and evals it; frees the string when done */
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/* Wrapper around dc_evalstr to avoid duplicating the free call
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* at all possible return points.
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*/
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static dc_status
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dc_eval_and_free_str DC_DECLARG((string))
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dc_data string DC_DECLEND
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{
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dc_status status;
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status = dc_evalstr(string);
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if (string.dc_type == DC_STRING)
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dc_free_str(&string.v.string);
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return status;
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}
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/* dc_func does the grunt work of figuring out what each input
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* character means; used by both dc_evalstr and dc_evalfile
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*
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* c -> the "current" input character under consideration
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* peekc -> the lookahead input character
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*/
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static dc_status
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dc_func DC_DECLARG((c, peekc))
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int c DC_DECLSEP
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int peekc DC_DECLEND
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{
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/* we occasionally need these for temporary data */
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/* Despite the GNU coding standards, it is much easier
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* to have these decared once here, since this function
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* is just one big switch statement.
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*/
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dc_data datum;
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int tmpint;
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switch (c){
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case '_': case '.':
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case '0': case '1': case '2': case '3':
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case '4': case '5': case '6': case '7':
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case '8': case '9': case 'A': case 'B':
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case 'C': case 'D': case 'E': case 'F':
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return DC_INT;
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case ' ':
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case '\t':
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case '\n':
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/* standard command separators */
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break;
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case '+': /* add top two stack elements */
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dc_binop(dc_add, dc_scale);
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break;
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case '-': /* subtract top two stack elements */
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dc_binop(dc_sub, dc_scale);
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break;
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case '*': /* multiply top two stack elements */
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dc_binop(dc_mul, dc_scale);
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break;
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case '/': /* divide top two stack elements */
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dc_binop(dc_div, dc_scale);
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break;
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case '%':
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/* take the remainder from division of the top two stack elements */
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dc_binop(dc_rem, dc_scale);
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break;
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case '^': /* exponientiation of the top two stack elements */
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dc_binop(dc_exp, dc_scale);
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break;
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case '<':
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/* eval register named by peekc if
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* less-than holds for top two stack elements
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_cmpop() < 0)
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if (dc_register_get(peekc, &datum) == DC_SUCCESS)
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if (dc_eval_and_free_str(datum) == DC_QUIT)
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return DC_QUIT;
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return DC_EATONE;
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case '=':
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/* eval register named by peekc if
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* equal-to holds for top two stack elements
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_cmpop() == 0)
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if (dc_register_get(peekc, &datum) == DC_SUCCESS)
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if (dc_eval_and_free_str(datum) == DC_QUIT)
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return DC_QUIT;
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return DC_EATONE;
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case '>':
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/* eval register named by peekc if
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* greater-than holds for top two stack elements
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_cmpop() > 0)
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if (dc_register_get(peekc, &datum) == DC_SUCCESS)
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if (dc_eval_and_free_str(datum) == DC_QUIT)
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return DC_QUIT;
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return DC_EATONE;
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case '?': /* read a lnie from standard-input and eval it */
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for (c=peekc; c=='\n'; c=getc(stdin))
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;
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ungetc(c, stdin);
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if (dc_eval_and_free_str(dc_readstring(stdin, '\n', '\n')) == DC_QUIT)
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return DC_QUIT;
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rescan_stdin = DC_TRUE;
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return DC_OKAY;
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case '[': /* read to balancing ']' into a dc_str */
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return DC_STR;
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case '!': /* read to newline and call system() on resulting string */
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return DC_SYSTEM;
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case '#': /* comment; skip remainder of current line */
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return DC_COMMENT;
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case 'c': /* clear whole stack */
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dc_clear_stack();
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break;
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case 'd': /* duplicate the datum on the top of stack */
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if (dc_top_of_stack(&datum) == DC_SUCCESS)
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dc_push(dc_dup(datum));
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break;
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case 'f': /* print list of all stack items */
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dc_printall(dc_obase);
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break;
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case 'i': /* set input base to value on top of stack */
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = 0;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_num2int(datum.v.number, DC_TRUE);
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if ( ! (2 <= tmpint && tmpint <= DC_IBASE_MAX) )
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fprintf(stderr,
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"%s: input base must be a number \
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between 2 and %d (inclusive)\n",
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progname, DC_IBASE_MAX);
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else
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dc_ibase = tmpint;
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}
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break;
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case 'k': /* set scale to value on top of stack */
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = -1;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_num2int(datum.v.number, DC_TRUE);
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if ( ! (tmpint >= 0) )
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fprintf(stderr,
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"%s: scale must be a nonnegative number\n",
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progname);
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else
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dc_scale = tmpint;
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}
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break;
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case 'l': /* "load" -- push value on top of register stack named
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* by peekc onto top of evaluation stack; does not
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* modify the register stack
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_register_get(peekc, &datum) == DC_SUCCESS)
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dc_push(datum);
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return DC_EATONE;
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case 'o': /* set output base to value on top of stack */
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = 0;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_num2int(datum.v.number, DC_TRUE);
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if ( ! (tmpint > 1) )
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fprintf(stderr,
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"%s: output base must be a number greater than 1\n",
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progname);
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else
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dc_obase = tmpint;
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}
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break;
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case 'p': /* print the datum on the top of stack */
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if (dc_top_of_stack(&datum) == DC_SUCCESS)
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dc_print(datum, dc_obase);
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break;
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case 'q': /* quit two levels of evaluation, posibly exiting program */
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unwind_depth = 2;
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unwind_noexit = DC_FALSE;
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return DC_QUIT;
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case 's': /* "store" -- replace top of register stack named
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* by peekc with the value popped from the top
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* of the evaluation stack
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_pop(&datum) == DC_SUCCESS)
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dc_register_set(peekc, datum);
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return DC_EATONE;
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case 'v': /* replace top of stack with its square root */
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if (dc_pop(&datum) == DC_SUCCESS){
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dc_num tmpnum;
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if (datum.dc_type != DC_NUMBER){
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fprintf(stderr,
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"%s: square root of nonnumeric attempted\n",
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progname);
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}else if (dc_sqrt(datum.v.number, dc_scale, &tmpnum) == DC_SUCCESS){
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dc_free_num(&datum.v.number);
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datum.v.number = tmpnum;
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dc_push(datum);
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}
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}
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break;
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case 'x': /* eval the datum popped from top of stack */
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if (dc_pop(&datum) == DC_SUCCESS){
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if (datum.dc_type == DC_STRING){
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if (dc_eval_and_free_str(datum) == DC_QUIT)
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return DC_QUIT;
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}else if (datum.dc_type == DC_NUMBER){
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dc_push(datum);
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}else{
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dc_garbage("at top of stack", -1);
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}
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}
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break;
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case 'z': /* push the current stack depth onto the top of stack */
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dc_push(dc_int2data(dc_tell_stackdepth()));
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break;
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case 'I': /* push the current input base onto the stack */
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dc_push(dc_int2data(dc_ibase));
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break;
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case 'K': /* push the current scale onto the stack */
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dc_push(dc_int2data(dc_scale));
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break;
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case 'L': /* pop a value off of register stack named by peekc
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* and push it onto the evaluation stack
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_register_pop(peekc, &datum) == DC_SUCCESS)
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dc_push(datum);
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return DC_EATONE;
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case 'O': /* push the current output base onto the stack */
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dc_push(dc_int2data(dc_obase));
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break;
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case 'P': /* print the value popped off of top-of-stack;
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* do not add a trailing newline
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*/
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if (dc_pop(&datum) == DC_SUCCESS){
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if (datum.dc_type == DC_STRING)
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dc_out_str(datum.v.string, DC_FALSE, DC_TRUE);
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else if (datum.dc_type == DC_NUMBER)
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dc_out_num(datum.v.number, dc_obase, DC_FALSE, DC_TRUE);
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else
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dc_garbage("at top of stack", -1);
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}
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break;
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case 'Q': /* quit out of top-of-stack nested evals;
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* pops value from stack;
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* does not exit program (stops short if necessary)
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*/
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if (dc_pop(&datum) == DC_SUCCESS){
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unwind_depth = 0;
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unwind_noexit = DC_TRUE;
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if (datum.dc_type == DC_NUMBER)
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unwind_depth = dc_num2int(datum.v.number, DC_TRUE);
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if (unwind_depth > 0)
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return DC_QUIT;
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fprintf(stderr,
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"%s: Q command requires a positive number\n",
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progname);
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}
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break;
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case 'S': /* pop a value off of the evaluation stack
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* and push it onto the register stack named by peekc
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*/
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_pop(&datum) == DC_SUCCESS)
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dc_register_push(peekc, datum);
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return DC_EATONE;
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case 'X': /* replace the number on top-of-stack with its scale factor */
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = 0;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_tell_scale(datum.v.number, DC_TRUE);
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dc_push(dc_int2data(tmpint));
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}
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break;
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case 'Z': /* replace the datum on the top-of-stack with its length */
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if (dc_pop(&datum) == DC_SUCCESS)
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dc_push(dc_int2data(dc_tell_length(datum, DC_TRUE)));
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break;
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case ':': /* store into array */
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = -1;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_num2int(datum.v.number, DC_TRUE);
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if (dc_pop(&datum) == DC_SUCCESS){
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if (tmpint < 0)
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fprintf(stderr,
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"%s: array index must be a nonnegative integer\n",
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progname);
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else
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dc_array_set(peekc, tmpint, datum);
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}
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}
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return DC_EATONE;
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case ';': /* retreive from array */
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if (peekc == EOF)
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return DC_EOF_ERROR;
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if (dc_pop(&datum) == DC_SUCCESS){
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tmpint = -1;
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if (datum.dc_type == DC_NUMBER)
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tmpint = dc_num2int(datum.v.number, DC_TRUE);
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if (tmpint < 0)
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fprintf(stderr,
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"%s: array index must be a nonnegative integer\n",
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progname);
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else
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dc_push(dc_array_get(peekc, tmpint));
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}
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return DC_EATONE;
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default: /* What did that user mean? */
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fprintf(stderr, "%s: ", progname);
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dc_show_id(stdout, c, " unimplemented\n");
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break;
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}
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return DC_OKAY;
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}
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/* takes a string and evals it */
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static dc_status
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dc_evalstr DC_DECLARG((string))
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dc_data string DC_DECLEND
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{
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const char *s;
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const char *end;
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const char *p;
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size_t len;
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int c;
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int peekc;
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int count;
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if (string.dc_type != DC_STRING){
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fprintf(stderr,
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"%s: eval called with non-string argument\n",
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progname);
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return DC_OKAY;
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}
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s = dc_str2charp(string.v.string);
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end = s + dc_strlen(string.v.string);
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while (s < end){
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c = *(const unsigned char *)s++;
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peekc = EOF;
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if (s < end)
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peekc = *(const unsigned char *)s;
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switch (dc_func(c, peekc)){
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case DC_OKAY:
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break;
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case DC_EATONE:
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if (peekc != EOF)
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++s;
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break;
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case DC_QUIT:
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if (unwind_depth > 0){
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--unwind_depth;
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return DC_QUIT;
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}
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return DC_OKAY;
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case DC_INT:
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input_str_string = s - 1;
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dc_push(dc_getnum(input_str, dc_ibase, &peekc));
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s = input_str_string;
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if (peekc != EOF)
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--s;
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break;
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case DC_STR:
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count = 1;
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for (p=s; p<end && count>0; ++p)
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if (*p == ']')
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--count;
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else if (*p == '[')
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++count;
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len = p - s;
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dc_push(dc_makestring(s, len-1));
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s = p;
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break;
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case DC_SYSTEM:
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s = dc_system(s);
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case DC_COMMENT:
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s = memchr(s, '\n', (size_t)(end-s));
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if (!s)
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s = end;
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++s;
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break;
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case DC_EOF_ERROR:
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fprintf(stderr, "%s: unexpected EOS\n", progname);
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return DC_OKAY;
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}
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}
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return DC_OKAY;
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}
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/* This is the main function of the whole DC program.
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* Reads the file described by fp, calls dc_func to do
|
||
* the dirty work, and takes care of dc_func's shortcomings.
|
||
*/
|
||
int
|
||
dc_evalfile DC_DECLARG((fp))
|
||
FILE *fp DC_DECLEND
|
||
{
|
||
int c;
|
||
int peekc;
|
||
dc_data datum;
|
||
|
||
for (c=getc(fp); c!=EOF; c=peekc){
|
||
peekc = getc(fp);
|
||
rescan_stdin = DC_FALSE;
|
||
switch (dc_func(c, peekc)){
|
||
case DC_OKAY:
|
||
if (rescan_stdin == DC_TRUE && fp == stdin)
|
||
peekc = getc(fp);
|
||
break;
|
||
case DC_EATONE:
|
||
peekc = getc(fp);
|
||
break;
|
||
case DC_QUIT:
|
||
if (unwind_noexit != DC_TRUE)
|
||
return DC_SUCCESS;
|
||
fprintf(stderr,
|
||
"%s: Q command argument exceeded string execution depth\n",
|
||
progname);
|
||
if (rescan_stdin == DC_TRUE && fp == stdin)
|
||
peekc = getc(fp);
|
||
break;
|
||
|
||
case DC_INT:
|
||
input_fil_fp = fp;
|
||
input_pushback = c;
|
||
ungetc(peekc, fp);
|
||
dc_push(dc_getnum(input_fil, dc_ibase, &peekc));
|
||
break;
|
||
case DC_STR:
|
||
ungetc(peekc, fp);
|
||
datum = dc_readstring(fp, '[', ']');
|
||
dc_push(datum);
|
||
peekc = getc(fp);
|
||
break;
|
||
case DC_SYSTEM:
|
||
ungetc(peekc, fp);
|
||
datum = dc_readstring(stdin, '\n', '\n');
|
||
(void)dc_system(dc_str2charp(datum.v.string));
|
||
dc_free_str(&datum.v.string);
|
||
peekc = getc(fp);
|
||
break;
|
||
case DC_COMMENT:
|
||
while (peekc!=EOF && peekc!='\n')
|
||
peekc = getc(fp);
|
||
if (peekc != EOF)
|
||
peekc = getc(fp);
|
||
break;
|
||
|
||
case DC_EOF_ERROR:
|
||
fprintf(stderr, "%s: unexpected EOF\n", progname);
|
||
return DC_FAIL;
|
||
}
|
||
}
|
||
return DC_SUCCESS;
|
||
}
|