NetBSD/gnu/usr.bin/dc/eval.c

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1994-12-01 07:26:47 +03:00
/*
* evaluate the dc language, from a FILE* or a string
*
* Copyright (C) 1994 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you can either send email to this
* program's author (see below) or write to: The Free Software Foundation,
* Inc.; 675 Mass Ave. Cambridge, MA 02139, USA.
*/
/* This is the only module which knows about the dc input language */
#include "config.h"
#include <stdio.h>
#ifdef HAVE_STRING_H
# include <string.h> /* memchr */
#else
# ifdef HAVE_MEMORY_H
# include <memory.h> /* memchr, maybe */
# else
# ifdef HAVE_STRINGS_H
# include <strings.h> /* memchr, maybe */
# endif
#endif
#endif
#include "dc.h"
#include "dc-proto.h"
typedef enum {
DC_OKAY, /* no further intervention needed for this command */
DC_EATONE, /* caller needs to eat the lookahead char */
DC_QUIT, /* quit out of unwind_depth levels of evaluation */
/* with the following return values, the caller does not have to
* fret about rescan_stdin's value
*/
DC_INT, /* caller needs to parse a dc_num from input stream */
DC_STR, /* caller needs to parse a dc_str from input stream */
DC_SYSTEM, /* caller needs to run a system() on next input line */
DC_COMMENT, /* caller needs to skip to the next input line */
DC_EOF_ERROR /* unexpected end of input; abort current eval */
} dc_status;
static int dc_ibase=10; /* input base, 2 <= dc_ibase <= DC_IBASE_MAX */
static int dc_obase=10; /* output base, 2 <= dc_obase */
static int dc_scale=0; /* scale (see user documentaton) */
/* forward reference */
static dc_status dc_evalstr DC_PROTO((dc_data));
/* for Quitting evaluations */
static int unwind_depth=0;
/* if true, active Quit will not exit program */
static dc_boolean unwind_noexit=DC_FALSE;
/* if true, stdin has been mucked with, dc_evalfile() needs to resyncronize */
static dc_boolean rescan_stdin=DC_FALSE;
/* input_fil and input_str are passed as arguments to dc_getnum */
/* used by the input_* functions: */
static FILE *input_fil_fp;
static const char *input_str_string;
/* Since we have a need for two characters of pushback, and
* ungetc() only guarantees one, we place the second pushback here
*/
static int input_pushback;
/* passed as an argument to dc_getnum */
static int
input_fil DC_DECLVOID()
{
if (input_pushback != EOF){
int c = input_pushback;
input_pushback = EOF;
return c;
}
return getc(input_fil_fp);
}
/* passed as an argument to dc_getnum */
static int
input_str DC_DECLVOID()
{
if (!*input_str_string)
return EOF;
return *input_str_string++;
}
/* takes a string and evals it; frees the string when done */
/* Wrapper around dc_evalstr to avoid duplicating the free call
* at all possible return points.
*/
static dc_status
dc_eval_and_free_str DC_DECLARG((string))
dc_data string DC_DECLEND
{
dc_status status;
status = dc_evalstr(string);
if (string.dc_type == DC_STRING)
dc_free_str(&string.v.string);
return status;
}
/* dc_func does the grunt work of figuring out what each input
* character means; used by both dc_evalstr and dc_evalfile
*
* c -> the "current" input character under consideration
* peekc -> the lookahead input character
*/
static dc_status
dc_func DC_DECLARG((c, peekc))
int c DC_DECLSEP
int peekc DC_DECLEND
{
/* we occasionally need these for temporary data */
/* Despite the GNU coding standards, it is much easier
* to have these decared once here, since this function
* is just one big switch statement.
*/
dc_data datum;
int tmpint;
switch (c){
case '_': case '.':
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
case '8': case '9': case 'A': case 'B':
case 'C': case 'D': case 'E': case 'F':
return DC_INT;
case ' ':
case '\t':
case '\n':
/* standard command separators */
break;
case '+': /* add top two stack elements */
dc_binop(dc_add, dc_scale);
break;
case '-': /* subtract top two stack elements */
dc_binop(dc_sub, dc_scale);
break;
case '*': /* multiply top two stack elements */
dc_binop(dc_mul, dc_scale);
break;
case '/': /* divide top two stack elements */
dc_binop(dc_div, dc_scale);
break;
case '%':
/* take the remainder from division of the top two stack elements */
dc_binop(dc_rem, dc_scale);
break;
case '^': /* exponientiation of the top two stack elements */
dc_binop(dc_exp, dc_scale);
break;
case '<':
/* eval register named by peekc if
* less-than holds for top two stack elements
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_cmpop() < 0)
if (dc_register_get(peekc, &datum) == DC_SUCCESS)
if (dc_eval_and_free_str(datum) == DC_QUIT)
return DC_QUIT;
return DC_EATONE;
case '=':
/* eval register named by peekc if
* equal-to holds for top two stack elements
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_cmpop() == 0)
if (dc_register_get(peekc, &datum) == DC_SUCCESS)
if (dc_eval_and_free_str(datum) == DC_QUIT)
return DC_QUIT;
return DC_EATONE;
case '>':
/* eval register named by peekc if
* greater-than holds for top two stack elements
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_cmpop() > 0)
if (dc_register_get(peekc, &datum) == DC_SUCCESS)
if (dc_eval_and_free_str(datum) == DC_QUIT)
return DC_QUIT;
return DC_EATONE;
case '?': /* read a lnie from standard-input and eval it */
for (c=peekc; c=='\n'; c=getc(stdin))
;
ungetc(c, stdin);
if (dc_eval_and_free_str(dc_readstring(stdin, '\n', '\n')) == DC_QUIT)
return DC_QUIT;
rescan_stdin = DC_TRUE;
return DC_OKAY;
case '[': /* read to balancing ']' into a dc_str */
return DC_STR;
case '!': /* read to newline and call system() on resulting string */
return DC_SYSTEM;
case '#': /* comment; skip remainder of current line */
return DC_COMMENT;
case 'c': /* clear whole stack */
dc_clear_stack();
break;
case 'd': /* duplicate the datum on the top of stack */
if (dc_top_of_stack(&datum) == DC_SUCCESS)
dc_push(dc_dup(datum));
break;
case 'f': /* print list of all stack items */
dc_printall(dc_obase);
break;
case 'i': /* set input base to value on top of stack */
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = 0;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_num2int(datum.v.number, DC_TRUE);
if ( ! (2 <= tmpint && tmpint <= DC_IBASE_MAX) )
fprintf(stderr,
"%s: input base must be a number \
between 2 and %d (inclusive)\n",
progname, DC_IBASE_MAX);
else
dc_ibase = tmpint;
}
break;
case 'k': /* set scale to value on top of stack */
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = -1;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_num2int(datum.v.number, DC_TRUE);
if ( ! (tmpint >= 0) )
fprintf(stderr,
"%s: scale must be a nonnegative number\n",
progname);
else
dc_scale = tmpint;
}
break;
case 'l': /* "load" -- push value on top of register stack named
* by peekc onto top of evaluation stack; does not
* modify the register stack
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_register_get(peekc, &datum) == DC_SUCCESS)
dc_push(datum);
return DC_EATONE;
case 'o': /* set output base to value on top of stack */
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = 0;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_num2int(datum.v.number, DC_TRUE);
if ( ! (tmpint > 1) )
fprintf(stderr,
"%s: output base must be a number greater than 1\n",
progname);
else
dc_obase = tmpint;
}
break;
case 'p': /* print the datum on the top of stack */
if (dc_top_of_stack(&datum) == DC_SUCCESS)
dc_print(datum, dc_obase);
break;
case 'q': /* quit two levels of evaluation, posibly exiting program */
unwind_depth = 2;
unwind_noexit = DC_FALSE;
return DC_QUIT;
case 's': /* "store" -- replace top of register stack named
* by peekc with the value popped from the top
* of the evaluation stack
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_pop(&datum) == DC_SUCCESS)
dc_register_set(peekc, datum);
return DC_EATONE;
case 'v': /* replace top of stack with its square root */
if (dc_pop(&datum) == DC_SUCCESS){
dc_num tmpnum;
if (datum.dc_type != DC_NUMBER){
fprintf(stderr,
"%s: square root of nonnumeric attempted\n",
progname);
}else if (dc_sqrt(datum.v.number, dc_scale, &tmpnum) == DC_SUCCESS){
dc_free_num(&datum.v.number);
datum.v.number = tmpnum;
dc_push(datum);
}
}
break;
case 'x': /* eval the datum popped from top of stack */
if (dc_pop(&datum) == DC_SUCCESS){
if (datum.dc_type == DC_STRING){
if (dc_eval_and_free_str(datum) == DC_QUIT)
return DC_QUIT;
}else if (datum.dc_type == DC_NUMBER){
dc_push(datum);
}else{
dc_garbage("at top of stack", -1);
}
}
break;
case 'z': /* push the current stack depth onto the top of stack */
dc_push(dc_int2data(dc_tell_stackdepth()));
break;
case 'I': /* push the current input base onto the stack */
dc_push(dc_int2data(dc_ibase));
break;
case 'K': /* push the current scale onto the stack */
dc_push(dc_int2data(dc_scale));
break;
case 'L': /* pop a value off of register stack named by peekc
* and push it onto the evaluation stack
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_register_pop(peekc, &datum) == DC_SUCCESS)
dc_push(datum);
return DC_EATONE;
case 'O': /* push the current output base onto the stack */
dc_push(dc_int2data(dc_obase));
break;
case 'P': /* print the value popped off of top-of-stack;
* do not add a trailing newline
*/
if (dc_pop(&datum) == DC_SUCCESS){
if (datum.dc_type == DC_STRING)
dc_out_str(datum.v.string, DC_FALSE, DC_TRUE);
else if (datum.dc_type == DC_NUMBER)
dc_out_num(datum.v.number, dc_obase, DC_FALSE, DC_TRUE);
else
dc_garbage("at top of stack", -1);
}
break;
case 'Q': /* quit out of top-of-stack nested evals;
* pops value from stack;
* does not exit program (stops short if necessary)
*/
if (dc_pop(&datum) == DC_SUCCESS){
unwind_depth = 0;
unwind_noexit = DC_TRUE;
if (datum.dc_type == DC_NUMBER)
unwind_depth = dc_num2int(datum.v.number, DC_TRUE);
if (unwind_depth > 0)
return DC_QUIT;
fprintf(stderr,
"%s: Q command requires a positive number\n",
progname);
}
break;
case 'S': /* pop a value off of the evaluation stack
* and push it onto the register stack named by peekc
*/
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_pop(&datum) == DC_SUCCESS)
dc_register_push(peekc, datum);
return DC_EATONE;
case 'X': /* replace the number on top-of-stack with its scale factor */
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = 0;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_tell_scale(datum.v.number, DC_TRUE);
dc_push(dc_int2data(tmpint));
}
break;
case 'Z': /* replace the datum on the top-of-stack with its length */
if (dc_pop(&datum) == DC_SUCCESS)
dc_push(dc_int2data(dc_tell_length(datum, DC_TRUE)));
break;
case ':': /* store into array */
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = -1;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_num2int(datum.v.number, DC_TRUE);
if (dc_pop(&datum) == DC_SUCCESS){
if (tmpint < 0)
fprintf(stderr,
"%s: array index must be a nonnegative integer\n",
progname);
else
dc_array_set(peekc, tmpint, datum);
}
}
return DC_EATONE;
case ';': /* retreive from array */
if (peekc == EOF)
return DC_EOF_ERROR;
if (dc_pop(&datum) == DC_SUCCESS){
tmpint = -1;
if (datum.dc_type == DC_NUMBER)
tmpint = dc_num2int(datum.v.number, DC_TRUE);
if (tmpint < 0)
fprintf(stderr,
"%s: array index must be a nonnegative integer\n",
progname);
else
dc_push(dc_array_get(peekc, tmpint));
}
return DC_EATONE;
default: /* What did that user mean? */
fprintf(stderr, "%s: ", progname);
dc_show_id(stdout, c, " unimplemented\n");
break;
}
return DC_OKAY;
}
/* takes a string and evals it */
static dc_status
dc_evalstr DC_DECLARG((string))
dc_data string DC_DECLEND
{
const char *s;
const char *end;
const char *p;
size_t len;
int c;
int peekc;
int count;
if (string.dc_type != DC_STRING){
fprintf(stderr,
"%s: eval called with non-string argument\n",
progname);
return DC_OKAY;
}
s = dc_str2charp(string.v.string);
end = s + dc_strlen(string.v.string);
while (s < end){
c = *(const unsigned char *)s++;
peekc = EOF;
if (s < end)
peekc = *(const unsigned char *)s;
switch (dc_func(c, peekc)){
case DC_OKAY:
break;
case DC_EATONE:
if (peekc != EOF)
++s;
break;
case DC_QUIT:
if (unwind_depth > 0){
--unwind_depth;
return DC_QUIT;
}
return DC_OKAY;
case DC_INT:
input_str_string = s - 1;
dc_push(dc_getnum(input_str, dc_ibase, &peekc));
s = input_str_string;
if (peekc != EOF)
--s;
break;
case DC_STR:
count = 1;
for (p=s; p<end && count>0; ++p)
if (*p == ']')
--count;
else if (*p == '[')
++count;
len = p - s;
dc_push(dc_makestring(s, len-1));
s = p;
break;
case DC_SYSTEM:
s = dc_system(s);
case DC_COMMENT:
s = memchr(s, '\n', (size_t)(end-s));
if (!s)
s = end;
++s;
break;
case DC_EOF_ERROR:
fprintf(stderr, "%s: unexpected EOS\n", progname);
return DC_OKAY;
}
}
return DC_OKAY;
}
/* This is the main function of the whole DC program.
* 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;
}