kernel: cons: Add initial ANSI escape seq impl

Signed-off-by: Ian Moffett <ian@osmora.org>

4 files changed, 249 insertions, 0 deletions

diff --git a/sys/dev/cons/cons.c b/sys/dev/cons/cons.c
index 75425f3..671d5f0 100644
--- a/sys/dev/cons/cons.c
+++ b/sys/dev/cons/cons.c
@@ -264,6 +264,14 @@ cons_fast_putch(struct cons_screen *scr, char c)
 {
     struct cons_char cc;
     struct cons_buf *bp;
+    int ansi;
+
+    ansi = ansi_feed(&scr->ansi_s, c);
+    if (ansi > 0) {
+        c = ASCII_NUL;
+    } else if (ansi < 0) {
+        c = ASCII_NUL;
+    }
 
     /* Handle specials */
     if (cons_handle_special(scr, c) == 0) {
diff --git a/sys/dev/cons/cons_ansi.c b/sys/dev/cons/cons_ansi.c
new file mode 100644
index 0000000..a91f1d3
--- /dev/null
+++ b/sys/dev/cons/cons_ansi.c
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <dev/cons/cons.h>
+#include <dev/cons/ansi.h>
+#include <string.h>
+
+__always_inline static inline bool
+is_valid_color(int c)
+{
+    return c >= '0' && c <= '7';
+}
+
+static inline void
+ansi_reset(struct ansi_state *statep)
+{
+    memset(statep, 0, sizeof(*statep));
+}
+
+/*
+ * Feed a byte into the ANSI escape sequence
+ * state machine.
+ *
+ * @statep: State machine pointer.
+ * @c: Byte to feed.
+ *
+ * On success, `c' is returned. On failure,
+ * 0 is returned. Values less than 0 indicate
+ * success with console attributes updated
+ * (ANSI_UPDATE_*).
+ */
+int
+ansi_feed(struct ansi_state *statep, char c)
+{
+    /* Standard colors */
+    static uint32_t colortab[] = {
+        ANSI_BLACK, ANSI_RED,
+        ANSI_GREEN, ANSI_YELLOW,
+        ANSI_BLUE, ANSI_MAGENTA,
+        ANSI_CYAN, ANSI_WHITE
+    };
+
+    /*
+     * Handle the control sequence introducer
+     * bytes.
+     */
+    switch (statep->csi) {
+    case 0: /* '\033' */
+        if (c != '\033') {
+            return 0;
+        }
+        statep->csi = 1;
+        statep->prev = c;
+        return c;
+    case 1: /* '[' */
+        if (c != '[') {
+            ansi_reset(statep);
+            return 0;
+        }
+        statep->csi = 2;
+        statep->prev = c;
+        return c;
+    }
+
+    if (!statep->set_fg && !statep->set_bg) {
+        /* Reset attributes? */
+        if (statep->reset_color) {
+            ansi_reset(statep);
+            cons_reset_color(&g_root_scr);
+            return ANSI_UPDATE_COLOR;
+        }
+
+        /* Mark attributes to be reset? */
+        if (c == '0') {
+            statep->reset_color = 1;
+            statep->prev = c;
+            return c;
+        }
+
+        /* Expect foreground */
+        if (c != '3') {
+            ansi_reset(statep);
+            return 0;
+        }
+        statep->set_fg = 1;
+        statep->prev = c;
+        return c;
+    }
+
+    if (statep->set_fg && c != ';') {
+        /* Make sure this is valid */
+        if (!is_valid_color(c)) {
+            ansi_reset(statep);
+            return 0;
+        }
+
+        /* Set the foreground */
+        statep->fg = colortab[c - '0'];
+        statep->set_bg = 1;
+        statep->set_fg = 0;
+        statep->prev = c;
+        return c;
+    }
+
+    if (statep->set_bg) {
+        if (c == ';') {
+            statep->prev = c;
+            return c;
+        }
+
+        /* Expect '4' after ';' */
+        if (statep->prev == ';' && c != '4') {
+            ansi_reset(statep);
+            return 0;
+        }
+
+        if (c == 'm') {
+            cons_update_color(&g_root_scr, statep->fg, statep->bg);
+            ansi_reset(statep);
+            return ANSI_UPDATE_COLOR;
+        }
+
+        /* Make sure this is valid */
+        if (!is_valid_color(c)) {
+            ansi_reset(statep);
+            return 0;
+        }
+
+        /* Set the background */
+        statep->bg = colortab[c - '0'];
+        statep->prev = c;
+        return c;
+    }
+
+    ansi_reset(statep);
+    return 0;
+}
diff --git a/sys/include/dev/cons/ansi.h b/sys/include/dev/cons/ansi.h
new file mode 100644
index 0000000..98d7618
--- /dev/null
+++ b/sys/include/dev/cons/ansi.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _CONS_ANSI_H_
+#define _CONS_ANSI_H_
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <sys/param.h>
+
+/* ANSI colors */
+#define ANSI_BLACK      0x000000
+#define ANSI_RED        0xAA0000
+#define ANSI_GREEN      0x00AA00
+#define ANSI_BLUE       0x0000AA
+#define ANSI_YELLOW     0xAA5500
+#define ANSI_MAGENTA    0xAA00AA
+#define ANSI_CYAN       0x00AAAA
+#define ANSI_WHITE      0xAAAAAA
+
+/* ANSI_FEED update codes */
+#define ANSI_UPDATE_COLOR  -1
+
+/*
+ * ANSI parser state machine.
+ *
+ * @prev: Previous char
+ * @csi: Encountered control seq introducer
+ * @reset_color: 1 if color is to be reset
+ * @set_fg: 1 if fg is being set
+ * @set_bg: 1 if bg is being set
+ * @fg: Foreground color
+ * @bg: Background color
+ * @flags: State flags
+ */
+struct ansi_state {
+    char prev;
+    uint8_t csi : 2;
+    uint8_t reset_color : 1;
+    uint8_t set_fg : 1;
+    uint8_t set_bg : 1;
+    uint32_t fg;
+    uint32_t bg;
+};
+
+int ansi_feed(struct ansi_state *statep, char c);
+
+#endif  /* !_CONS_ANSI_H_ */
diff --git a/sys/include/dev/cons/cons.h b/sys/include/dev/cons/cons.h
index fb254cb..13153b2 100644
--- a/sys/include/dev/cons/cons.h
+++ b/sys/include/dev/cons/cons.h
@@ -34,6 +34,7 @@
 #include <sys/spinlock.h>
 #include <dev/video/fbdev.h>
 #include <dev/cons/consvar.h>
+#include <dev/cons/ansi.h>
 
 struct cons_char {
     char c;
@@ -45,6 +46,7 @@ struct cons_char {
 
 struct cons_screen {
     struct fbdev fbdev;
+    struct ansi_state ansi_s;
     uint32_t fg;
     uint32_t bg;