From 52dab7fc85d877e80e3032f0afabae906adebad8 Mon Sep 17 00:00:00 2001
From: hachem <im@hachem.wtf>
Date: Sun, 4 Oct 2026 16:03:42 +0200
Subject: feat: fs tree and free list alloc

---
 user/calc.c    |  6 ++++++
 user/hexview.c | 32 +++++++++++++++++++++++++++-----
 user/save.c    | 45 +++++++++++++++++++++++++++++++++++++++++++++
 user/user.h    | 17 ++++++++++++++++-
 4 files changed, 94 insertions(+), 6 deletions(-)
 create mode 100644 user/save.c

(limited to 'user')

diff --git a/user/calc.c b/user/calc.c
index 2d0e3f8..cf5b1d2 100644
--- a/user/calc.c
+++ b/user/calc.c
@@ -23,6 +23,7 @@ void _start(void)
         int valid = 1;
         int saw_number = 0;
         int position = 0;
+
         while (position < length)
         {
             char character = line[position];
@@ -31,11 +32,13 @@ void _start(void)
                 position++;
                 continue;
             }
+
             if (is_digit(character))
             {
                 long value = 0;
                 while (position < length && is_digit(line[position]))
                     value = value * 10 + (line[position++] - '0');
+
                 if (operator == '+')
                     accumulator += value;
                 else if (operator == '-')
@@ -52,6 +55,7 @@ void _start(void)
                     }
                     accumulator = (operator == '/') ? accumulator / value : accumulator % value;
                 }
+
                 saw_number = 1;
             }
             else if (character == '+' || character == '-' || character == '*'
@@ -67,6 +71,7 @@ void _start(void)
                 break;
             }
         }
+
         if (valid && saw_number)
         {
             put("= ");
@@ -74,5 +79,6 @@ void _start(void)
             put("\n");
         }
     }
+
     sys_exit(0);
 }
diff --git a/user/hexview.c b/user/hexview.c
index 6354338..c211b44 100644
--- a/user/hexview.c
+++ b/user/hexview.c
@@ -19,12 +19,22 @@ static void put_hex32(unsigned long value)
 #define PAGE 256
 #define COLS 16
 
-void _start(void)
+void _start(const char* arg, unsigned long arglen)
 {
-    put("hexview, type a filename\nfile: ");
     char name[64];
-    read_line(name, 64);
-    put("\n");
+
+    if (arglen > 0 && arglen < 64)
+    {
+        for (unsigned long i = 0; i < arglen; i++)
+            name[i] = arg[i];
+        name[arglen] = 0;
+    }
+    else
+    {
+        put("hexview, type a filename\nfile: ");
+        read_line(name, 64);
+        put("\n");
+    }
 
     long size = sys_fs_size(name);
     if (size < 0)
@@ -35,6 +45,7 @@ void _start(void)
 
     unsigned long offset = 0;
     char buffer[PAGE];
+
     for (;;)
     {
         long count = sys_fs_read(name, offset, buffer, PAGE);
@@ -61,6 +72,7 @@ void _start(void)
                 else
                     put("   ");
             }
+
             put(" ");
             for (int column = 0; column < COLS && row + column < count; column++)
             {
@@ -73,8 +85,18 @@ void _start(void)
             put("\n");
         }
 
-        put("[n]ext [p]rev [q]uit > ");
+        put("[n]ext [p]rev [q]uit (or up/down arrows) > ");
         char key = (char)sys_read();
+        if (key == 27) // ESC
+        {
+            sys_read();
+            char final = (char)sys_read();
+            if (final == 'A')
+                key = 'p';
+            else if (final == 'B')
+                key = 'n';
+        }
+
         put("\n");
         if (key == 'q')
             break;
diff --git a/user/save.c b/user/save.c
new file mode 100644
index 0000000..b3664f4
--- /dev/null
+++ b/user/save.c
@@ -0,0 +1,45 @@
+#include "user.h"
+
+void _start(const char* arg, unsigned long arglen)
+{
+    if (arglen == 0 || arglen >= 64)
+    {
+        put("usage: run save <path>\n");
+        sys_exit(1);
+    }
+
+    char name[64];
+    for (unsigned long i = 0; i < arglen; i++)
+        name[i] = arg[i];
+    name[arglen] = 0;
+
+    put("saving to ");
+    put(name);
+    put(" -- type lines, a single . saves\n");
+
+    char buffer[4096];
+    int length = 0;
+    for (;;)
+    {
+        char line[256];
+        int n = read_line(line, 256);
+        put("\n");
+        if (n == 1 && line[0] == '.')
+            break;
+        for (int i = 0; i < n && length < 4000; i++)
+            buffer[length++] = line[i];
+        if (length < 4000)
+            buffer[length++] = '\n';
+    }
+
+    if (sys_fs_write(name, buffer, (unsigned long)length))
+    {
+        put("saved ");
+        put(name);
+        put("\n");
+    }
+    else
+        put("write failed\n");
+
+    sys_exit(0);
+}
diff --git a/user/user.h b/user/user.h
index 676326b..635dc86 100644
--- a/user/user.h
+++ b/user/user.h
@@ -1,4 +1,4 @@
-// shared syscall stubs + tiny helpers for revel ring 3 programs
+// shared syscall stubs
 
 static long sys_write(const char* buffer, unsigned long length)
 {
@@ -37,6 +37,16 @@ static long sys_fs_read(const char* name, unsigned long offset, char* buffer, un
     return result;
 }
 
+static long sys_fs_write(const char* name, const char* buffer, unsigned long length)
+{
+    long result;
+    __asm__ volatile("int $0x80"
+                     : "=a"(result)
+                     : "a"(6L), "D"(name), "S"(buffer), "d"(length)
+                     : "memory");
+    return result;
+}
+
 static void put(const char* string)
 {
     unsigned long length = 0;
@@ -78,20 +88,25 @@ static void put_int(long value)
     int length = 0;
     int negative = value < 0;
     unsigned long magnitude = negative ? (unsigned long)(-value) : (unsigned long)value;
+
     if (magnitude == 0)
         buffer[length++] = '0';
+
     while (magnitude > 0)
     {
         buffer[length++] = (char)('0' + magnitude % 10);
         magnitude /= 10;
     }
+
     if (negative)
         buffer[length++] = '-';
+
     for (int left = 0, right = length - 1; left < right; left++, right--)
     {
         char swap = buffer[left];
         buffer[left] = buffer[right];
         buffer[right] = swap;
     }
+
     sys_write(buffer, length);
 }
-- 
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