dev/c/tex_parser/tex_parser.c

#include "tex_parser.h"

#include <string.h>
#include <ctype.h>
#include "tex_parser_tags.h"
#include "zalloc_ext.h"
#include "zalloc.h"
#include "c_const.h"

/* only for debug */
#define __TEX_PARSER_DEBUG 0
#include <stdio.h>


int tex_parse(const char *source, size_t len, struct zerror_s *error)
{
	error->code = 0;
	error->message = NULL;

	if (!len)
		len = strlen(source);

	enum where_e
	{
		IN_UNDEF = 0, // undefined place
		IN_COMMENT, // any comment
		IN_TAG, // any tag
		IN_TAG_UNKNOWN, // unknown tag
		IN_SPACE, // space, \tag  { for example
		IN_TAGPARM, // in \tag{} curly braces
		IN_TAG_BEGIN,
		IN_TAG_CLINE,
		IN_TAG_END,
		IN_TAG_ENDFOOT,
		IN_TAG_ENDHEAD,
		IN_TAG_HLINE,
		IN_TAG_HSPACE,
		IN_TAG_MULTICOLUMN,
		IN_TAG_MULTIROW,
		IN_TAG_TABULARNEWLINE,
		IN_FORMULA, // in $...$

	} where_stack[MAX_TEX_STACK_LEVEL] = {IN_UNDEF};

	char *tag = NULL;
	size_t i = 0;
	size_t tex_level = 0;

	for (i = 0; i < len; i++) {

		/* stack checking */
		if (tex_level + 1 == MAX_TEX_STACK_LEVEL) {
			error->code = (int)i;
			error->message = "stack overflow";
			return error->code;
		}

		/* read one character from input stream */
		char c = source[i];
		#ifdef __TEX_PARSER_DEBUG
			printf("tex_level = %lu, c = %c\n", tex_level, c);
		#endif

		/* looking at where_stack and encountered character */
		switch (where_stack[tex_level]) {
		case IN_UNDEF:
			if (c == '\\') {
				tag = zfree_null(tag);
				where_stack[++tex_level] = IN_TAG;


			} else if (isspace(c)) {
				where_stack[++tex_level] = IN_SPACE;

			} else if (c == '%') {
				where_stack[++tex_level] = IN_COMMENT;

			} else if (isgraph(c) || c < 0) {

			} else {
				error->code = (int)i;
				error->message = "unexpected symbol (IN_UDEF)";
				return error->code;
			}
		break;

		case IN_COMMENT:
			if (c == '\r' || c == '\n') {
				where_stack[tex_level--] = IN_UNDEF;
			}
		break;

		case IN_TAG:
			if (isalnum(c)) {
				tag = zalloc_append8_str(tag, c);

			} else if (!tag && (c == '\\' || c == ','
			           || c == '%' || c == '_')) {
				where_stack[tex_level--] = IN_UNDEF;

			} else if (!tag) {
				error->code = (int)i;
				error->message = "empty tag (IN_TAG)";
				return error->code;

			} else {
				if (!strcmp(tag, TEX_TAG_BEGIN))
					where_stack[tex_level] = IN_TAG_BEGIN;

				else if (!strcmp(tag, TEX_TAG_CLINE))
					where_stack[tex_level] = IN_TAG_CLINE;

				else if (!strcmp(tag, TEX_TAG_END))
					where_stack[tex_level] = IN_TAG_END;

				else if (!strcmp(tag, TEX_TAG_ENDFOOT))
					where_stack[tex_level] = IN_TAG_ENDFOOT;

				else if (!strcmp(tag, TEX_TAG_ENDHEAD))
					where_stack[tex_level] = IN_TAG_ENDHEAD;

				else if (!strcmp(tag, TEX_TAG_HLINE))
					where_stack[tex_level] = IN_TAG_HLINE;

				else if (!strcmp(tag, TEX_TAG_HSPACE))
					where_stack[tex_level] = IN_TAG_HSPACE;

				else if (!strcmp(tag, TEX_TAG_MULTICOLUMN))
					where_stack[tex_level] = IN_TAG_MULTICOLUMN;

				else if (!strcmp(tag, TEX_TAG_MULTIROW))
					where_stack[tex_level] = IN_TAG_MULTIROW;

				else if (!strcmp(tag, TEX_TAG_TABULARNEWLINE))
					where_stack[tex_level] = IN_TAG_TABULARNEWLINE;

				else
					where_stack[tex_level] = IN_TAG_UNKNOWN;

				#ifdef __TEX_PARSER_DEBUG
					printf("\\%s\n", tag);
				#endif
				tag = zfree_null(tag);

				i--;
			}
		break;

		case IN_SPACE:
			if (!isspace(c)) {
				where_stack[tex_level--] = IN_UNDEF;
				i--;
			}
		break;

		case IN_TAGPARM:
			if (c == '{' || c == '[') { // tag params
				where_stack[++tex_level] = IN_TAGPARM;

			} else if (c == '}' || c == ']') { // end tag params
				where_stack[tex_level--] = IN_UNDEF;

			} else if (c == '\\') { // new tag
				tag = zfree_null(tag);
				where_stack[++tex_level] = IN_TAG;

			} else if (isspace(c)) {
				where_stack[++tex_level] = IN_SPACE;

			} else if (c == '%') {
				where_stack[++tex_level] = IN_COMMENT;

			} else if (isgraph(c) || c < 0) {

			} else {
				error->code = (int)i;
				error->message = "unexpected symbol (IN_TAGPARM)";
				return error->code;
			}
		break;

		case IN_TAG_UNKNOWN:
		case IN_TAG_BEGIN:
		case IN_TAG_CLINE:
		case IN_TAG_END:
		case IN_TAG_ENDFOOT:
		case IN_TAG_ENDHEAD:
		case IN_TAG_HLINE:
		case IN_TAG_HSPACE:
		case IN_TAG_MULTICOLUMN:
		case IN_TAG_MULTIROW:
		case IN_TAG_TABULARNEWLINE:
			switch(where_stack[tex_level]) {

			case IN_TAG_UNKNOWN:

			break;

			case IN_TAG_BEGIN:

			break;

			case IN_TAG_CLINE:

			break;

			case IN_TAG_END:

			break;

			case IN_TAG_ENDFOOT:

			break;

			case IN_TAG_ENDHEAD:

			break;

			case IN_TAG_HLINE:

			break;

			case IN_TAG_HSPACE:

			break;

			case IN_TAG_MULTICOLUMN:

			break;

			case IN_TAG_MULTIROW:

			break;

			case IN_TAG_TABULARNEWLINE:

			break;

			default:
			error->code = (int)i;
			error->message = "unknown error (IN_TAG_))";
			return error->code;
			break;
			}

			if (c == '{' || c == '[')
				where_stack[++tex_level] = IN_TAGPARM;

			else if (c == '}' || c == ']') {
				where_stack[tex_level--] = IN_UNDEF;
				i--;

			} else if (c == '\\') {
				tag = zfree_null(tag);
				where_stack[tex_level] = IN_TAG;

			} else if (isspace(c))
				where_stack[++tex_level] = IN_SPACE;

			else if (c == '%')
				where_stack[++tex_level] = IN_COMMENT;

			else if (isgraph(c) || c < 0) {

			} else {
				error->code = (int)i;
				error->message = "unexpected symbol (IN_TAG_)";
				return error->code;
			}
		break;

		case IN_FORMULA:

		break;

		default:
			error->code = (int)i;
			error->message = "unknown error";
			return error->code;
		break;
		}
	}

	return 0;
}