ch_type.c

linux下的Ｃ语言开发

/********************************************************
 * ch_type package					*
 *							*
 * This module is used to determine the type of  	*
 * various characters.					*
 *							*
 * Public functions:					*
 *	init_char_type -- initialize the table.		*
 * 	is_char_type -- is a character of a given type?	*
 *	get_char_type -- given char, return type	*
 ********************************************************/
#include <stdio.h>

#include "ch_type.h"

/* Define the type information array */
static enum CHAR_TYPE type_info[256];	
static int ch_setup = 0;	/* True if character type info setup */
/********************************************************
 * fill_range -- fill in a range of types for the 	*
 *	character type class				*
 *							*
 * Parameters						*
 *	start, end -- range of items to fill in 	*
 *	type -- type to use for filling			*
 ********************************************************/
static void fill_range(int start, int end, enum CHAR_TYPE type)
{
    int cur_ch;	/* Character we are handling now */

    for (cur_ch = start; cur_ch <= end; ++cur_ch) {
	type_info[cur_ch] = type;
    }
}

/*********************************************************
 * init_char_type -- initialize the char type table      *
 *********************************************************/
static void init_char_type(void)
{
    fill_range(0, 255, C_WHITE);

    fill_range('A', 'Z', C_ALPHA);
    fill_range('a', 'z', C_ALPHA);
    type_info['_'] = C_ALPHA;

    fill_range('0', '9', C_DIGIT);

    type_info['!'] = C_OPERATOR;
    type_info['#'] = C_OPERATOR;
    type_info['$'] = C_OPERATOR;
    type_info['%'] = C_OPERATOR;
    type_info['^'] = C_OPERATOR;
    type_info['&'] = C_OPERATOR;
    type_info['*'] = C_OPERATOR;
    type_info['-'] = C_OPERATOR;
    type_info['+'] = C_OPERATOR;
    type_info['='] = C_OPERATOR;
    type_info['|'] = C_OPERATOR;
    type_info['~'] = C_OPERATOR;
    type_info[','] = C_OPERATOR;
    type_info[':'] = C_OPERATOR;
    type_info['?'] = C_OPERATOR;
    type_info['.'] = C_OPERATOR;
    type_info['<'] = C_OPERATOR;
    type_info['>'] = C_OPERATOR;

    type_info['/'] = C_SLASH;
    type_info['\n'] = C_NEWLINE;

    type_info['('] = C_L_PAREN;
    type_info[')'] = C_R_PAREN;

    type_info['{'] = C_L_CURLY;
    type_info['}'] = C_R_CURLY;

    type_info['"'] = C_DOUBLE;
    type_info['\''] = C_SINGLE;
}

/********************************************************
 * is_char_type -- Determine if a character belongs to 	*
 * 		a given character type.			*
 *							*
 * Parameters						*
 *	ch -- Character to check			*
 *	kind -- type to check it for			*
 *							*
 * Returns:						*
 *	0 -- character is not of the specified kind	*
 *	1 -- character is of the specified kind.	*
 ********************************************************/
int is_char_type(int ch, enum CHAR_TYPE kind)
{
    if (!ch_setup) {
       init_char_type();
       ch_setup = 1;
    }

    if (ch == EOF) return (kind == C_EOF);

    switch (kind) {
	case C_HEX_DIGIT:
	    if (type_info[ch] == C_DIGIT)
		return (1);
	    if ((ch >= 'A') && (ch <= 'F')) 
		return (1);
	    if ((ch >= 'a') && (ch <= 'f')) 
		return (1);
	    return (0);
	case C_ALPHA_NUMERIC:
	    return ((type_info[ch] == C_ALPHA) ||
		    (type_info[ch] == C_DIGIT));
	default:
	    return (type_info[ch] == kind);
    }
};

/********************************************************
 * get_char_type -- Given a character, return its type.*
 *							*
 * Note: We return the simple types.  Compoisite types	*
 * such as C_HEX_DIGIT and C_ALPHA_NUMERIC are not	*
 * returned.						*
 *							*
 * Parameters:						*
 *	ch -- character who's type we want.		*
 *							*
 * Returns						*
 *	character type.					*
 ********************************************************/
enum CHAR_TYPE get_char_type(int ch) {
    if (!ch_setup) {
       init_char_type();
       ch_setup = 1;
    }

    if (ch == EOF) return (C_EOF);

    return (type_info[ch]);
}