begin syntax highlighting

level.cpp

@@ -41,14 +41,41 @@ enum editorKey {
 	PAGE_DOWN
 };
 
+enum editorHighlight {
+	HL_NORMAL = 0,
+	HL_COMMENT,
+	HL_MLCOMMENT,
+	HL_KEYWORD1,
+	HL_KEYWORD2,
+	HL_STRING,
+	HL_NUMBER,
+	HL_MATCH
+};
+
+#define HL_HIGHLIGHT_NUMBERS (1<<0)
+#define HL_HIGHLIGHT_STRINGS (1<<1)
+
 /*** data ***/
 
+struct editorSyntax {
+	char *filetype;
+	char **filematch;
+	char **keywords;
+	char *singleline_comment_start;
+	char *multiline_comment_start;
+	char *multiline_comment_end;
+	int flags;
+};
+
 // erow stands for "editor row"
 typedef struct erow {
+	int idx;
 	int size;
 	int rsize;
 	char *chars;
 	char *render;
+	unsigned char *hl;
+	int hl_open_comment;
 } erow;
 
 struct editorConfig {
@@ -64,11 +91,35 @@ struct editorConfig {
 	char *filename;
 	char statusmsg[80];
 	time_t statusmsg_time;
+	struct editorSyntax *syntax;
 	struct termios orig_termios;
 };
 
 struct editorConfig E;
 
+/*** filetypes ***/
+
+const char *C_HL_extensions[] = { ".c", ".h", ".cpp", NULL };
+const char *C_HL_keywords[] = {
+	"switch", "if", "while", "for", "break", "continue", "return", "else",
+	"struct", "union", "typedef", "static", "enum", "class", "case",
+
+	"int|", "long|", "double|", "float|", "char|", "unsinged|", "signed|",
+	"void|", NULL
+};
+
+const struct editorSyntax HLDB[] = {
+  {
+    "c",
+    C_HL_extensions,
+    C_HL_keywords,
+    "//", "/*", "*/",
+    HL_HIGHLIGHT_NUMBERS | HL_HIGHLIGHT_STRINGS
+  },
+};
+
+#define HLDB_ENTRIES (sizeof(HLDB) / sizeof(HLDB[0]))
+
 /*** prototypes ***/
 
 void editorSetStatusMessage(const char* fmt, ...);
@@ -197,6 +248,166 @@ int getWindowSize(int *rows, int *cols) {
 	}
 }
 
+/*** syntax highlighting ***/
+
+int is_seperator(int c) {
+	return isspace(c) || c == '\0' || strchr(",.()+-/*=~%<>[];", c) != NULL;
+}
+
+void editorUpdateSyntax(erow *row) {
+	row->hl = (unsigned char*)realloc(row->hl, row->rsize);
+	memset(row->hl, HL_NORMAL, row->rsize);
+
+	if (E.syntax == NULL) return;
+
+	char **keywords = E.syntax->keywords;
+
+	char *scs = E.syntax->singleline_comment_start;
+	char *mcs = E.syntax->multiline_comment_start;
+	char *mce = E.syntax->multiline_comment_end;
+
+	int scs_len = scs ? strlen(scs) : 0;
+	int mcs_len = mcs ? strlen(mcs) : 0;
+	int mce_len = mce ? strlen(mce) : 0;
+
+	int prev_sep = 1;
+	int in_string = 0;
+	int in_comment = (row->idx > 0 && E.row[row->idx - 1].hl_open_comment);
+
+	int i = 0;
+	while (i < row->rsize) {
+		char c = row->render[i];
+		unsigned char prev_hl = (i > 0) ? row->hl[i - 1] : HL_NORMAL;
+
+		if (scs_len && !in_string && !in_comment) {
+			if (!strncmp(&row->render[i], scs, scs_len)) {
+				memset(&row->hl[i], HL_COMMENT, row->rsize - i);
+				break;
+			}
+		}
+
+		if (mcs_len &mce_len && !in_string) {
+			if (in_comment) {
+				row->hl[i] = HL_MLCOMMENT;
+				if (!strncmp(&row->render[i], mce, mce_len)) {
+					memset(&row->hl[i], HL_MLCOMMENT, mce_len);
+					i += mce_len;
+					in_comment = 0;
+					prev_sep = 1;
+					continue;
+				} else {
+					i++;
+					continue;
+				}
+			} else if (!strncmp(&row->render[i], mcs, mcs_len)) {
+				memset(&row->hl[i], HL_MLCOMMENT, mcs_len);
+				i += mcs_len;
+				in_comment = 1;
+				continue;
+			}
+		}
+
+		if (E.syntax->flags & HL_HIGHLIGHT_STRINGS) {
+			if (in_string) {
+				row->hl[i] = HL_STRING;
+				if (c == '\\' && i + 1 < row->rsize) {
+					row->hl[i + 1] = HL_STRING;
+					i += 2;
+					continue;
+				}
+				if (c == in_string) in_string = 0;
+				i++;
+				prev_sep = 1;
+				continue;
+			} else {
+				if (c == '"' || c == '\'') {
+					in_string = c;
+					row->hl[i] = HL_STRING;
+					i++;
+					continue;
+				}
+			}
+		}
+
+		if (E.syntax->flags & HL_HIGHLIGHT_NUMBERS) {
+			if ((isdigit(c) && (prev_sep || prev_hl == HL_NUMBER)) ||
+					(c == '.' && prev_hl == HL_NUMBER)) {
+				row->hl[i] = HL_NUMBER;
+				i++;
+				prev_sep = 0;
+				continue;
+			}
+		}
+
+		if (prev_sep) {
+			int j;
+			for (j = 0; keywords[j]; j++) {
+				int klen = strlen(keywords[j]);
+				int kw2 = keywords[j][klen - 1] == '|';
+				if (kw2) klen--;
+
+				if (!strncmp(&row->render[i], keywords[j], klen) &&
+						is_seperator(row->render[i + klen])) {
+					memset(&row->hl[i], kw2 ? HL_KEYWORD2 : HL_KEYWORD1, klen);
+					i += klen;
+					break;
+				}
+			}
+			if (keywords[j] != NULL) {
+				prev_sep = 0;
+				continue;
+			}
+		}
+
+		prev_sep = is_seperator(c);
+		i++;
+	}
+
+	int changed = (row->hl_open_comment != in_comment);
+	row->hl_open_comment = in_comment;
+	if (changed && row->idx + 1 < E.numrows)
+		editorUpdateSyntax(&E.row[row->idx + 1]);
+}
+
+int editorSyntaxToColor(int hl) {
+	switch (hl) {
+		case HL_COMMENT:
+		case HL_MLCOMMENT: return 36;
+		case HL_KEYWORD1: return 33;
+		case HL_KEYWORD2: return 32;
+		case HL_STRING: return 35;
+		case HL_NUMBER: return 31;
+		case HL_MATCH: return 34;
+		default: return 37;
+	}
+}
+
+void editorSelectSyntaxHighlight() {
+	E.syntax = NULL;
+	if (E.filename == NULL) return;
+
+	char *ext = strrchr(E.filename, '.');
+
+	for (unsigned int j = 0; j < HLDB_ENTRIES; j++) {
+		struct editorSyntax *s = &HLDB[j];
+		unsigned int i = 0;
+		while (s->filematch[i]) {
+			int is_ext = (s->filematch[i][0] == '.');
+			if ((is_ext && ext && !strcmp(ext, s->filematch[i])) ||
+					(!is_ext && strstr(E.filename, s->filematch[i]))) {
+				E.syntax = s;
+
+				for (int filerow = 0; filerow < E.numrows; filerow++) {
+					editorUpdateSyntax(&E.row[filerow]);
+				}
+
+				return;
+			}
+			i++;
+		}
+	}
+}
+
 /*** row operations ***/
 
 int editorRowCxToRx(erow *row, int cx) {
@@ -240,6 +451,8 @@ void editorUpdateRow(erow *row) {
 	}
 	row->render[idx] = '\0';
 	row->rsize = idx;
+
+	editorUpdateSyntax(row);
 }
 
 void editorInsertRow(int at, const char *s, size_t len) {
@@ -247,6 +460,9 @@ void editorInsertRow(int at, const char *s, size_t len) {
 	
 	E.row = (erow*)realloc(E.row, sizeof(erow) * (E.numrows + 1));
 	memmove(&E.row[at + 1], &E.row[at], sizeof(erow) * (E.numrows - at));
+	for (int j = at + 1; j <= E.numrows; j++) E.row[j].idx++;
+
+	E.row[at].idx = at;
 
 	E.row[at].size = len;
 	E.row[at].chars = (char*)malloc(len + 1);
@@ -255,6 +471,8 @@ void editorInsertRow(int at, const char *s, size_t len) {
 
 	E.row[at].rsize = 0;
 	E.row[at].render = NULL;
+	E.row[at].hl = NULL;
+	E.row[at].hl_open_comment = 0;
 	editorUpdateRow(&E.row[at]);
 
 	E.numrows++;
@@ -264,12 +482,14 @@ void editorInsertRow(int at, const char *s, size_t len) {
 void editorFreeRow(erow* row) {
 	free(row->render);
 	free(row->chars);
+	free(row->hl);
 }
 
 void editorDelRow(int at) {
 	if (at < 0 || at >= E.numrows) return;
 	editorFreeRow(&E.row[at]);
 	memmove(&E.row[at], &E.row[at + 1], sizeof(erow) * (E.numrows - at - 1));
+	for (int j = at; j < E.numrows - 1; j++) E.row[j].idx--;
 	E.numrows--;
 	E.dirty++;
 }
@@ -372,6 +592,8 @@ void editorOpen(char *filename) {
 	free(E.filename);
 	E.filename = strdup(filename);
 
+	editorSelectSyntaxHighlight();
+
 	FILE *fp = fopen(filename, "r");
 	if (!fp) die("fopen");
 
@@ -396,6 +618,7 @@ void editorSave() {
 			editorSetStatusMessage("Save aborted");
 			return;
 		}
+		editorSelectSyntaxHighlight();
 	}
 
 	int len;
@@ -425,6 +648,15 @@ void editorFindCallback(char *query, int key) {
 	static int last_match = -1;
 	static int direction = 1;
 
+	static int saved_hl_line;
+	static char *saved_hl = NULL;
+
+	if (saved_hl) {
+		memcpy(E.row[saved_hl_line].hl, saved_hl, E.row[saved_hl_line].rsize);
+		free(saved_hl);
+		saved_hl = NULL;
+	}
+
 	if (key == '\r' || key == ESCAPE_CONST) {
 		last_match = -1;
 		direction = 1;
@@ -450,6 +682,11 @@ void editorFindCallback(char *query, int key) {
 			E.cy = current;
 			E.cx = editorRowRxToCx(row, match - row->render);
 			E.rowoff = E.numrows;
+
+			saved_hl_line = current;
+			saved_hl = (char*)malloc(row->rsize);
+			memcpy(saved_hl, row->hl, row->rsize);
+			memset(&row->hl[match - row->render], HL_MATCH, strlen(query));
 			break;
 		}
 	}
@@ -529,7 +766,38 @@ void editorDrawRows(struct abuf *ab) {
 			int len = E.row[filerow].rsize - E.coloff;
 			if (len < 0) len = 0;
 			if (len > E.screencols) len = E.screencols;
-			abAppend(ab, &E.row[filerow].render[E.coloff], len);
+			char *c = &E.row[filerow].render[E.coloff];
+			unsigned char *hl = &E.row[filerow].hl[E.coloff];
+			int current_color = -1;
+			for (int j = 0; j < len; j++) {
+				if (iscntrl(c[j])) {
+					char sym = (c[j] <= 26) ? '@' + c[j] : '?';
+					abAppend(ab, "\x1b[7m", 4);
+					abAppend(ab, &sym, 1);
+					abAppend(ab, "\x1b[m", 3);
+					if (current_color != -1) {
+						char buf[16];
+						int clen = snprintf(buf, sizeof(buf), "\x1b[%dm", current_color);
+						abAppend(ab, buf, clen);
+					}
+				} else if (hl[j] == HL_NORMAL) {
+					if (current_color != -1) {
+						abAppend(ab, "\x1b[39m", 5);
+						current_color = -1;
+					}
+					abAppend(ab, &c[j], 1);
+				} else {
+					int color = editorSyntaxToColor(hl[j]);
+					if (color != current_color) {
+						current_color = color;
+						char buf[16];
+						int clen = snprintf(buf, sizeof(buf), "\x1b[%dm", color);
+						abAppend(ab, buf, clen);
+					}
+					abAppend(ab, &c[j], 1);
+				}
+			}
+			abAppend(ab, "\x1b[39m", 5);
 		}
 
 		abAppend(ab, "\x1b[K", 3);
@@ -543,8 +811,8 @@ void editorDrawStatusBar(struct abuf* ab) {
 	int len = snprintf(status, sizeof(status), "%.20s - %d lines %s",
 		E.filename ? E.filename : "[No Name]", E.numrows,
 		E.dirty ? "(modified)" : "");
-	int rlen = snprintf(rstatus, sizeof(rstatus), "%d/%d",
+	int rlen = snprintf(rstatus, sizeof(rstatus), "%s | %d/%d",
-		E.cy + 1, E.numrows);
+    E.syntax ? E.syntax->filetype : "no ft", E.cy + 1, E.numrows);
 	if (len > E.screencols) len = E.screencols;
 	abAppend(ab, status, len);
 	while (len < E.screencols) {
@@ -756,6 +1024,7 @@ void initEditor() {
 	E.filename = NULL;
 	E.statusmsg[0] = '\0';
 	E.statusmsg_time = 0;
+	E.syntax = NULL;
 
 	if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
 	E.screenrows -= 2;