gnuplot/src/scanner.c at 5.4.8 · gnuplot/gnuplot · GitHub

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/* GNUPLOT - scanner.c */

/*[

* Permission to use, copy, and distribute this software and its

* documentation for any purpose with or without fee is hereby granted,

* provided that the above copyright notice appear in all copies and

* that both that copyright notice and this permission notice appear

* in supporting documentation.

* Permission to modify the software is granted, but not the right to

* distribute the complete modified source code. Modifications are to

* be distributed as patches to the released version. Permission to

* distribute binaries produced by compiling modified sources is granted,

* provided you

* 1. distribute the corresponding source modifications from the

* released version in the form of a patch file along with the binaries,

* 2. add special version identification to distinguish your version

* in addition to the base release version number,

* 3. provide your name and address as the primary contact for the

* support of your modified version, and

* 4. retain our contact information in regard to use of the base

* software.

* Permission to distribute the released version of the source code along

* with corresponding source modifications in the form of a patch file is

* granted with same provisions 2 through 4 for binary distributions.

* This software is provided "as is" without express or implied warranty

* to the extent permitted by applicable law.

]*/

#include "scanner.h"

#include "alloc.h"

#include "command.h"

#include "util.h"

int curly_brace_count;

static int get_num(char str[]);

static void substitute(char **strp, size_t *str_lenp, int current);

#define isident(c) (isalnum((unsigned char)(c)) || (c) == '_' || ALLOWED_8BITVAR(c))

#define LBRACE '{'

#define RBRACE '}'

#define APPEND_TOKEN {token[t_num].length++; current++;}

static int t_num; /* number of token I'm working on */

TBOOLEAN

legal_identifier(char *p)

{

if (!p || !(*p) || isdigit((unsigned char)*p))

return FALSE;

while (*p) {

if (!isident(*p))

return FALSE;

p++;

}

return TRUE;

}

* scanner() breaks expression[] into lexical units, storing them in token[].

* The total number of tokens found is returned as the function

* value. Scanning will stop when '\0' is found in expression[], or

* when token[] is full. extend_input_line() is called to extend

* expression array if needed.

* Scanning is performed by following rules:

* Current char token should contain

* ------------- -----------------------

* 1. alpha,_ all following alpha-numerics

* 2. digit 0 or more following digits, 0 or 1 decimal point,

* 0 or more digits, 0 or 1 'e' or 'E',

* 0 or more digits.

* 3. ^,+,-,/ only current char

* %,~,(,)

* [,],;,:,

* ?,comma

* $

* 4. &,|,=,* current char; also next if next is same

* 5. !,<,> current char; also next if next is =

* 6. ", ' all chars up until matching quote

* 7. # this token cuts off scanning of the line (DFK).

* 8. ` (command substitution: all characters through the

* matching backtic are replaced by the output of

* the contained command, then scanning is restarted.)

* EAM Jan 2010: Bugfix. No rule covered an initial period. This caused

* string concatenation to fail for variables whose first

* character is 'E' or 'e'. Now we add a 9th rule:

* 9. . A period may be a token by itself (string concatenation)

* or the start of a decimal number continuing with a digit

* white space between tokens is ignored

int

scanner(char **expressionp, size_t *expressionlenp)

{

int current; /* index of current char in expression[] */

char *expression = *expressionp;

int quote;

char brace;

curly_brace_count = 0;

for (current = t_num = 0; expression[current] != NUL; current++) {

if (t_num + 1 >= token_table_size) {

/* leave space for dummy end token */

extend_token_table();

}

if (isspace((unsigned char) expression[current]))

continue; /* skip the whitespace */

token[t_num].start_index = current;

token[t_num].length = 1;

token[t_num].is_token = TRUE; /* to start with... */

if (expression[current] == '`') {

substitute(expressionp, expressionlenp, current);

expression = *expressionp; /* expression might have moved */

current--;

continue;

}

/* allow _ to be the first character of an identifier */

/* allow 8bit characters in identifiers */

if (isalpha((unsigned char)expression[current])

|| (expression[current] == '_')

|| ALLOWED_8BITVAR(expression[current])) {

while (isident(expression[current + 1]))

APPEND_TOKEN;

} else if (isdigit((unsigned char) expression[current])) {

token[t_num].is_token = FALSE;

token[t_num].length = get_num(&expression[current]);

current += (token[t_num].length - 1);

} else if (expression[current] == '.') {

/* Rule 9 */

if (isdigit((unsigned char)expression[current+1])) {

token[t_num].is_token = FALSE;

token[t_num].length = get_num(&expression[current]);

current += (token[t_num].length - 1);

} /* do nothing if the . is a token by itself */

} else if (expression[current] == LBRACE) {

int partial;

token[t_num].is_token = FALSE;

token[t_num].l_val.type = CMPLX;

partial = sscanf(&expression[++current], "%lf , %lf %c",

&token[t_num].l_val.v.cmplx_val.real,

&token[t_num].l_val.v.cmplx_val.imag,

&brace);

if (partial <= 0) {

curly_brace_count++;

token[t_num++].is_token = TRUE;

current--;

continue;

}

if (partial != 3 || brace != RBRACE)

int_error(t_num, "invalid complex constant");

token[t_num].length += 2;

while (expression[++current] != RBRACE) {

token[t_num].length++;

if (expression[current] == NUL) /* { for vi % */

int_error(t_num, "no matching '}'");

}

} else if (expression[current] == '\'' ||

expression[current] == '\"') {

token[t_num].length++;

quote = expression[current];

while (expression[++current] != quote) {

if (!expression[current]) {

expression[current] = quote;

expression[current + 1] = NUL;

break;

} else if (quote == '\"'

&& expression[current] == '\\'

&& expression[current + 1]) {

current++;

token[t_num].length += 2;

} else if (quote == '\"' && expression[current] == '`') {

substitute(expressionp, expressionlenp, current);

expression = *expressionp; /* it might have moved */

current--;

} else if (quote == '\''

&& expression[current+1] == '\''

&& expression[current+2] == '\'') {

/* look ahead: two subsequent single quotes

* -> take them in

current += 2;

token[t_num].length += 3;

} else

token[t_num].length++;

}

} else

switch (expression[current]) {

case '#':

goto endline; /* ignore the rest of the line */

case '^':

case '+':

case '-':

case '/':

case '%':

case '~':

case '(':

case ')':

case '[':

case ']':

case ';':

case ':':

case '?':

case ',':

break;

case '$': /* The # in $# is _not_ a comment */

if (expression[current + 1] == '#')

APPEND_TOKEN;

break;

case '}': /* complex constants will not end up here */

curly_brace_count--;

break;

case '&':

case '|':

case '=':

case '*':

if (expression[current] == expression[current + 1])

APPEND_TOKEN;

break;

case '!':

case '>':

if (expression[current + 1] == '=')

APPEND_TOKEN;

if (expression[current + 1] == '>')

APPEND_TOKEN;

break;

case '<':

if (expression[current + 1] == '=')

APPEND_TOKEN;

if (expression[current + 1] == '<')

APPEND_TOKEN;

break;

default:

int_error(t_num, "invalid character %c",expression[current]);

}

++t_num; /* next token if not white space */

}

endline: /* comments jump here to ignore line */

/* Now kludge an extra token which points to '\0' at end of expression[].

This is useful so printerror() looks nice even if we've fallen off the

line. */

token[t_num].start_index = current;

token[t_num].length = 0;

/* print 3+4 then print 3+ is accepted without

* this, since string is ignored if it is not

* a token

token[t_num].is_token = TRUE;

return (t_num);

}

static int

get_num(char str[])

{

int count = 0;

char *endptr;

token[t_num].is_token = FALSE;

token[t_num].l_val.type = INTGR; /* assume unless . or E found */

while (isdigit((unsigned char) str[count]))

count++;

if (str[count] == '.') {

token[t_num].l_val.type = CMPLX;

/* swallow up digits until non-digit */

while (isdigit((unsigned char) str[++count]));

/* now str[count] is other than a digit */

}

if (str[count] == 'e' || str[count] == 'E') {

token[t_num].l_val.type = CMPLX;

count++;

if (str[count] == '-' || str[count] == '+')

count++;

if (!isdigit((unsigned char) str[count])) {

token[t_num].start_index += count;

int_error(t_num, "expecting exponent");

}

while (isdigit((unsigned char) str[++count]));

}

if (token[t_num].l_val.type == INTGR) {

long long lval;

errno = 0;

lval = strtoll(str, &endptr, 0);

if (!errno) {

count = endptr - str;

/* Linux and Windows implementations of POSIX function strtoll() differ.*/

/* I don't know which is "correct" but returning 0 causes an infinite */

/* loop on input "0x" as the scanner fails to progress. */

if (count == 0) count++;

if ((token[t_num].l_val.v.int_val = lval) == lval)

return(count);

if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) {

if ((long long unsigned int)lval == (long long unsigned int)token[t_num].l_val.v.int_val)

return(count);

}

int_warn(t_num, "integer overflow; changing to floating point");

token[t_num].l_val.type = CMPLX;

/* Fall through */

}

token[t_num].l_val.v.cmplx_val.imag = 0.0;

token[t_num].l_val.v.cmplx_val.real = strtod(str, &endptr);

count = endptr - str;

return (count);

}

/* substitute output from ` `

* *strp points to the input string. (*strp)[current] is expected to

* be the initial back tic. Characters through the following back tic

* are replaced by the output of the command. extend_input_line()

* is called to extend *strp array if needed.

static void

substitute(char **strp, size_t *str_lenp, int current)

{

char *last;

char c;

char *str, *pgm, *rest = NULL;

char *output;

size_t pgm_len, rest_len = 0;

int output_pos;

/* forgive missing closing backquote at end of line */

str = *strp + current;

last = str;

while (*++last) {

if (*last == '`')

break;

}

pgm_len = last - str;

pgm = gp_alloc(pgm_len, "command string");

safe_strncpy(pgm, str + 1, pgm_len); /* omit ` to leave room for NUL */

/* save rest of line, if any */

if (*last) {

last++; /* advance past ` */

rest_len = strlen(last) + 1;

if (rest_len > 1) {

rest = gp_alloc(rest_len, "input line copy");

strcpy(rest, last);

}

/* do system call */

(void) do_system_func(pgm, &output);

free(pgm);

/* now replace ` ` with output */

output_pos = 0;

while ((c = output[output_pos++])) {

/* This was added in 3.5, so it's been a long time,

* but deleting internal line breaks makes no sense.

* Removed for 5.4

* A trailing \n is still removed, however.

if ((output[output_pos] != '\0') || (c != '\n'))

(*strp)[current++] = c;

if (current == *str_lenp)

extend_input_line();

}

(*strp)[current] = 0;

free(output);

/* tack on rest of line to output */

if (rest) {

while (current + rest_len > *str_lenp)

extend_input_line();

strcpy(*strp + current, rest);

free(rest);

}

screen_ok = FALSE;

}

gnuplot/src/scanner.c at 5.4.8 · gnuplot/gnuplot · GitHub

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