Initial commit.

1 files changed, 254 insertions, 0 deletions

diff --git a/src/lexer.c b/src/lexer.c
new file mode 100644
index 0000000..5863ef6
--- /dev/null
+++ b/src/lexer.c
@@ -0,0 +1,254 @@
+/*
+Copyright (C) 2017 Paweł Redman
+
+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 3
+of the License, 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, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+*/
+
+#include "shared.h"
+#include <ctype.h>
+
+void vstr_init(vstr_t *vstr)
+{
+	memset(vstr, 0, sizeof(*vstr));
+}
+
+void vstr_destroy(vstr_t *vstr)
+{
+	free(vstr->data);
+}
+
+void vstr_clear(vstr_t *vstr)
+{
+	vstr->size = 0;
+}
+
+static int vstr_enlarge(vstr_t *vstr)
+{
+	size_t new_alloc;
+
+	new_alloc = (vstr->alloc + 4) * 3 / 2;
+
+	vstr->data = realloc(vstr->data, new_alloc);
+	if (!vstr->data)
+		return 1;
+
+	vstr->alloc = new_alloc;
+	return 0;
+}
+
+int vstr_putc(vstr_t *vstr, char ch)
+{
+	// note: keep at least one character free at all times for vstr_termz
+	if (vstr->size + 2 > vstr->alloc)
+		if (vstr_enlarge(vstr))
+			return -ENOMEM;
+
+	vstr->data[vstr->size] = ch;
+	vstr->size++;
+	return 0;
+}
+
+int vstr_cmp(vstr_t *vstr, const char *str)
+{
+	size_t len;
+
+	len = strlen(str);
+	if (vstr->size < len)
+		len = vstr->size;
+
+	return memcmp(vstr->data, str, len);
+}
+
+char *vstr_strdup(vstr_t *vstr)
+{
+	char *str;
+
+	str = malloc(vstr->size + 1);
+	if (!str)
+		return NULL;
+
+	memcpy(str, vstr->data, vstr->size);
+	str[vstr->size] = 0;
+
+	return str;
+}
+
+char *vstr_to_cstr(vstr_t *vstr)
+{
+	vstr->data[vstr->size] = '\0';
+	return vstr->data;
+}
+
+int lexer_open(lexer_state_t *ls, const char *path, vstr_t *token)
+{
+	ls->error = 0;
+	ls->path = path;
+
+	ls->fp = fopen(path, "r");
+	if (!ls->fp)
+		return -errno;
+
+	ls->eof = false;
+
+	ls->token = token;
+	ls->buf_e = ls->buf_c = ls->buf;
+	ls->cc = ls->lc = ls->Cc = 0;
+
+	ls->in_token = false;
+	ls->in_quote = false;
+	ls->in_comment = false;
+
+	return 0;
+}
+
+void lexer_close(lexer_state_t *ls)
+{
+	vstr_destroy(ls->token);
+	fclose(ls->fp);
+}
+
+//RETURN VALUES
+//	<0 on error
+//	0 on success
+//	note: sets ls->eof to true if there's no more data left
+static int fill_buffer(lexer_state_t *ls)
+{
+	size_t read;
+
+	read = fread(ls->buf, 1, sizeof(ls->buf), ls->fp);
+	if (read < sizeof(ls->buf)) {
+		if (ferror(ls->fp))
+			return -errno;
+
+		ls->eof = true;
+	}
+
+	ls->buf_c = ls->buf;
+	ls->buf_e = ls->buf + read;
+	return 0;
+}
+
+//RETURN VALUES
+//	-ENOMEM
+//	-EAGAIN when the buffer runs out
+//	0 on success
+//	1 when no data is left
+static int read_buffer(lexer_state_t *ls)
+{
+	while (ls->buf_c < ls->buf_e) {
+		bool ret_token = false;
+
+		if (*ls->buf_c == '\n') {
+			ls->lc++;
+			ls->Cc = 0;
+		}
+
+		if (ls->in_comment) {
+			if (*ls->buf_c == '\n')
+				ls->in_comment = false;
+		} else if (isspace(*ls->buf_c) && !ls->in_quote) {
+			if (ls->in_token) {
+				ls->in_token = false;
+				ret_token = true;
+			}
+		} else if (*ls->buf_c == '/' && (ls->cc && ls->last == '/')) {
+			ls->in_comment = true;
+			ls->in_token = false;
+
+			ls->token->size--; // remove the first slash
+			if (ls->token->size)
+				ret_token = true;
+		} else if (*ls->buf_c == '\"' &&
+		           (ls->cc && ls->last != '\\')) {
+			ls->in_quote = !ls->in_quote;
+
+			if (!ls->in_quote) {
+				ls->in_token = false;
+				ret_token = true;
+			}
+		} else {
+			if (!ls->in_token) {
+				ls->in_token = true;
+			}
+		}
+
+		if (ls->in_token)
+			if (vstr_putc(ls->token, *ls->buf_c)) {
+				ls->error = ENOMEM;
+				return -ENOMEM;
+			}
+
+		ls->last = *ls->buf_c;
+		ls->buf_c++;
+		ls->cc++;
+		ls->Cc++;
+
+		if (ret_token)
+			return 0;
+	}
+
+	if (ls->eof) {
+		if (ls->token->size > 0)
+			return 0;
+		return 1;
+	}
+
+	return -EAGAIN;
+}
+
+//RETURN VALUES
+//	<0 on error
+//	0 on success
+//	1 when no data is left
+int lexer_get_token(lexer_state_t *ls)
+{
+	int ret;
+
+	vstr_clear(ls->token);
+
+	while (1) {
+		ret = read_buffer(ls);
+		if (ret != -EAGAIN)
+			return ret;
+
+		ret = fill_buffer(ls);
+		if (ret < 0)
+			return ret;
+	}
+}
+
+void lexer_perror(lexer_state_t *ls, const char *fmt, ...)
+{
+	va_list vl;
+
+	eprintf("%s:%zu:%zu: ", ls->path, ls->lc + 1, ls->Cc + 1);
+
+	if (ls->error) {
+		perror(NULL);
+	} else {
+		va_start(vl, fmt);
+		vfprintf(stderr, fmt, vl);
+		va_end(vl);
+	}
+}
+
+void lexer_perror_eg(lexer_state_t *ls, const char *expected)
+{
+	if (ls->eof && ls->buf_c == ls->buf_e)
+		lexer_perror(ls, "expected %s, got EOF\n", expected);
+	else
+		lexer_perror(ls, "expected %s, got \"%s\"\n", expected,
+		             vstr_to_cstr(ls->token));
+}