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Diffstat (limited to 'dc/eval.c')
| -rw-r--r-- | dc/eval.c | 682 |
1 files changed, 682 insertions, 0 deletions
diff --git a/dc/eval.c b/dc/eval.c new file mode 100644 index 0000000..21592d9 --- /dev/null +++ b/dc/eval.c @@ -0,0 +1,682 @@ +/* + * evaluate the dc language, from a FILE* or a string + * + * Copyright (C) 1994, 1997, 1998, 2000 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. + * 59 Temple Place, Suite 330 + * Boston, MA 02111 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_FALSE, DC_TRUE} dc_boolean; + +typedef enum { + DC_OKAY = DC_SUCCESS, /* 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 stdin_lookahead'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_NEGCMP, /* caller needs to re-call dc_func() with `negcmp' set */ + + 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) */ + +/* for Quitting evaluations */ +static int unwind_depth=0; + +/* if true, active Quit will not exit program */ +static dc_boolean unwind_noexit=DC_FALSE; + +/* + * Used to synchronize lookahead on stdin for '?' command. + * If set to EOF then lookahead is used up. + */ +static int stdin_lookahead=EOF; + + +/* 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 int +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 + * negcmp -> negate comparison test (for <,=,> commands) + */ +static dc_status +dc_func DC_DECLARG((c, peekc, negcmp)) + int c DC_DECLSEP + int peekc DC_DECLSEP + int negcmp DC_DECLEND +{ + /* we occasionally need these for temporary data */ + /* Despite the GNU coding standards, it is much easier + * to have these declared 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 '~': + /* Do division on the top two stack elements. Return the + * quotient as next-to-top of stack and the remainder as + * top-of-stack. + */ + dc_binop2(dc_divrem, dc_scale); + break; + case '|': + /* Consider the top three elements of the stack as (base, exp, mod), + * where mod is top-of-stack, exp is next-to-top, and base is + * second-from-top. Mod must be non-zero, exp must be non-negative, + * and all three must be integers. Push the result of raising + * base to the exp power, reduced modulo mod. If we had base in + * register b, exp in register e, and mod in register m then this + * is conceptually equivalent to "lble^lm%", but it is implemented + * in a more efficient manner, and can handle arbritrarily large + * values for exp. + */ + dc_triop(dc_modexp, 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) == !negcmp ) + 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) == !negcmp ) + 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) == !negcmp ) + 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 line from standard-input and eval it */ + if (stdin_lookahead != EOF){ + ungetc(stdin_lookahead, stdin); + stdin_lookahead = EOF; + } + if (dc_eval_and_free_str(dc_readstring(stdin, '\n', '\n')) == DC_QUIT) + return DC_QUIT; + return DC_OKAY; + case '[': /* read to balancing ']' into a dc_str */ + return DC_STR; + case '!': /* read to newline and call system() on resulting string */ + if (peekc == '<' || peekc == '=' || peekc == '>') + return DC_NEGCMP; + return DC_SYSTEM; + case '#': /* comment; skip remainder of current line */ + return DC_COMMENT; + + case 'a': /* Convert top of stack to an ascii character. */ + if (dc_pop(&datum) == DC_SUCCESS){ + char tmps; + if (datum.dc_type == DC_NUMBER){ + tmps = (char) dc_num2int(datum.v.number, DC_TOSS); + }else if (datum.dc_type == DC_STRING){ + tmps = *dc_str2charp(datum.v.string); + dc_free_str(&datum.v.string); + }else{ + dc_garbage("at top of stack", -1); + } + dc_push(dc_makestring(&tmps, 1)); + } + break; + 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_TOSS); + 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_TOSS); + 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 'n': /* print the value popped off of top-of-stack; + * do not add a trailing newline + */ + if (dc_pop(&datum) == DC_SUCCESS) + dc_print(datum, dc_obase, DC_NONL, DC_TOSS); + break; + 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_TOSS); + 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, + * with a trailing newline + */ + if (dc_top_of_stack(&datum) == DC_SUCCESS) + dc_print(datum, dc_obase, DC_WITHNL, DC_KEEP); + break; + case 'q': /* quit two levels of evaluation, posibly exiting program */ + unwind_depth = 1; /* the return below is the first level of returns */ + unwind_noexit = DC_FALSE; + return DC_QUIT; + case 'r': /* rotate (swap) the top two elements on the stack + */ + if (dc_pop(&datum) == DC_SUCCESS) { + dc_data datum2; + int two_status; + two_status = dc_pop(&datum2); + dc_push(datum); + if (two_status == DC_SUCCESS) + dc_push(datum2); + } + break; + 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': + /* Pop the value off the top of a stack. If it is + * a number, dump out the integer portion of its + * absolute value as a "base UCHAR_MAX+1" byte stream; + * if it is a string, just print it. + * In either case, do not append a trailing newline. + */ + if (dc_pop(&datum) == DC_SUCCESS){ + if (datum.dc_type == DC_NUMBER) + dc_dump_num(datum.v.number, DC_TOSS); + else if (datum.dc_type == DC_STRING) + dc_out_str(datum.v.string, DC_NONL, DC_TOSS); + 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_TOSS); + if (unwind_depth-- > 0) + return DC_QUIT; + unwind_depth = 0; /* paranoia */ + fprintf(stderr, + "%s: Q command requires a number >= 1\n", + progname); + } + break; +#if 0 + case 'R': /* pop a value off of the evaluation stack,; + * rotate the top + remaining stack elements that many + * places forward (negative numbers mean rotate + * backward). + */ + if (dc_pop(&datum) == DC_SUCCESS){ + tmpint = 0; + if (datum.dc_type == DC_NUMBER) + tmpint = dc_num2int(datum.v.number, DC_TOSS); + dc_stack_rotate(tmpint); + } + break; +#endif + 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_TOSS); + 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_TOSS))); + 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_TOSS); + 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_TOSS); + 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 */ +int +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; + int negcmp; + int next_negcmp = 0; + + 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; + negcmp = next_negcmp; + next_negcmp = 0; + switch (dc_func(c, peekc, negcmp)){ + 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; + else + ++s; + break; + case DC_NEGCMP: + next_negcmp = 1; + 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; + int negcmp; + int next_negcmp = 0; + dc_data datum; + + stdin_lookahead = EOF; + for (c=getc(fp); c!=EOF; c=peekc){ + peekc = getc(fp); + /* + * The following if() is the only place where ``stdin_lookahead'' + * might be set to other than EOF: + */ + if (fp == stdin) + stdin_lookahead = peekc; + negcmp = next_negcmp; + next_negcmp = 0; + switch (dc_func(c, peekc, negcmp)){ + case DC_OKAY: + if (stdin_lookahead != peekc && 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 (stdin_lookahead != peekc && 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_NEGCMP: + next_negcmp = 1; + break; + + case DC_EOF_ERROR: + fprintf(stderr, "%s: unexpected EOF\n", progname); + return DC_FAIL; + } + } + return DC_SUCCESS; +} |