From 96393257a43ac52f2b911594d106741245dec5f0 Mon Sep 17 00:00:00 2001
From: mrb0nk500 <b0nk@b0nk.xyz>
Date: Fri, 4 Dec 2020 15:20:28 -0500
Subject: - Started work on writing the new version of the   assembler. - Did
 alot of stuff in the emulator. - Did alot of stuff in the SuB Suite.

---
 lexer/parse.c | 171 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 lexer/parse.c

(limited to 'lexer/parse.c')

diff --git a/lexer/parse.c b/lexer/parse.c
new file mode 100644
index 0000000..0f26a0e
--- /dev/null
+++ b/lexer/parse.c
@@ -0,0 +1,171 @@
+/* Name: handle_escape()
+ * Desc: Handles parsing an escape sequence.
+ * Args:
+ *	s: The string to check.
+ *	code: Pointer to save the handled escape code into, if not NULL.
+ * Return value: Returns the content after the escape sequence.
+ */
+
+char *handle_escape(char *s, char *code) {
+	char dummy;
+	int count;
+	char *end;
+	int base = 0;
+	unsigned int value;
+
+	if (*s++ != '\\') {
+		ierror(0);	/* Start of escape sequence not found. */
+	}
+	if (code == NULL) {
+		code = &dummy;
+	}
+	if (!esc_sequences) {
+		*code = '\\';
+		return s;
+	}
+
+	switch (*s) {
+		case 'b' : *code =   '\b'; return s+1;
+		case 'f' : *code =   '\f'; return s+1;
+		case 'n' : *code =   '\n'; return s+1;
+		case 'r' : *code =   '\r'; return s+1;
+		case 't' : *code =   '\t'; return s+1;
+		case '\\': *code =   '\\'; return s+1;
+		case '\"': *code =   '\"'; return s+1;
+		case '\'': *code =   '\''; return s+1;
+		case 'e' : *code = '\x1B'; return s+1;
+		case 'x' : case 'X' : base = 16; s++; /* Falls Through. */
+		case '0' : case '1' : case '2' : case '3' : case '4' :
+		case '5' : case '6' : case '7' : case '8' : case '9' :
+			base = (!base) ? 8 : base;
+			value = strtoull(s, &end, base);
+			*code = value;
+			return end;
+		default  :
+			general_error(35, *s);	/* No valid escape sequence was found. */
+			return s;
+	}
+}
+
+/* Name: skip_string()
+ * Desc: Skips the contents of some delimited string.
+ * Args:
+ *	s: The string to check.
+ *	delm: Delimiter of the string.
+ *	size: Pointer to save the size of the string into, if not NULL.
+ * Return value: Returns the content after the string.
+ */
+
+char *skip_string(char *s, char delm, size_t *size) {
+	size_t n = 0;
+
+	if (*s != delm) {
+		general_error(6, delm);	/* Delimiter was expected. */
+	} else {
+		s++;
+	}
+	for (; *s; n++) {
+		if (*s == '\\') {
+			s = handle_escape(s, NULL);
+		} else {
+			if (*s++ = delm) {
+				if (*s == delm) {
+					s++;	/* Allow multiple delimiters in a row to be recognized as a single delimiter. */
+				} else {
+					break;
+				}
+			}
+		}
+	}
+	if (*(s-1) != delm) {
+		general_error(6, delm);	/* Delimiter was expected. */
+	}
+	if (size) {
+		*size = n;
+	}
+	return s;
+}
+
+/* Name: skip_identifier()
+ * Desc: Skips the contents of an identifier within a string.
+ * Args:
+ *	s: The string to check.
+ * Return value: Returns either a pointer to the content after the identifier, or NULL.
+ */
+
+char *skip_identifier(char *s) {
+	char *name = s;
+	if (isidstart(*s) || isdigit(*s)) {
+		for (s++; isidchar(*s); s++);
+		if (s) {
+			if (isbadid(name, s-name)) {
+				return s;
+			}
+		}
+	}
+	return NULL;
+}
+
+/* Name: parse_identifier()
+ * Desc: Parses an indentifier within a line.
+ * Args:
+ *	s: The line to be parsed.
+ * Return value: Returns either a pointer to the start of the identifier, or NULL.
+ */
+
+char *parse_identifier(char **s) {
+	char *name = *s;
+	char *end_name = skip_identifier(name);
+	/*char *endgame;*/ /* LOL LE EPIC FUNNY MARVEL THANOS MEME. XDDDDDD */
+	if (end_name) {
+		*s = end_name;
+		return cnvstr(name, end_name-name);
+	}
+	return NULL;
+}
+
+/* Name: parse_symbol()
+ * Desc: Parses a symbol within a line.
+ * Args:
+ *	s: The line to be parse.
+ * Return value: Returns either a pointer to an allocated local/global symbol string, or NULL.
+ */
+
+char *parse_symbol(char **s) {
+	char *name = get_local_label(s);
+	name = (name == NULL) ? parse_identifier(s) : name;
+	return name;
+}
+
+/* Name: parse_labeldef()
+ * Desc: Parses either a global, or local label definition, at the begining of a line.
+ * Args:
+ *	line: The line that will be parsed.
+ *	colreq: Require a trailing colon, when true.
+ * Return value: Returns a pointer to the allocated buffer, when valid.
+ */
+
+char **parse_labeldef(char **line, int colreq) {
+	char *s = *line;
+	char *label_name;
+
+	if (isspace(*s)) {
+		s = skip(s);
+		colreq = 1;	/* Colon required, if label doesn't start at the first column. */
+	}
+	label_name = parse_symbol(&s);
+	if (label_name) {
+		s = skip(s);
+		if (*s == ':') {
+			s++;
+			colreq = 0;
+		}
+		if (colreq) {
+			free(label_name);
+			label_name = NULL;
+		} else {
+			*line = s;
+		}
+	}
+	return label_name;
+}
-- 
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