Reduced memory usage of default printf

Author: totalspectrum

Changelog.txt

@@ -1,5 +1,6 @@
 Version 6.2.0
 - Made `virtual` a reserved keyword in C++
+- Reduced memory usage of default printf
 
 Version 6.1.6
 - Added ability to double quote to include quotes in literal BASIC strings

include/libc/unix/posixio.c

@@ -56,6 +56,8 @@ static vfs_file_t __filetab[_MAX_FILES] = {
         0, /* close function */
         &_rxtxioctl,
         &__dummy_flush, /* flush function */
+        0, /* lseek */
+        0, 0, /* pointer cache */
     },
     /* stdout */
     {
@@ -71,6 +73,8 @@ static vfs_file_t __filetab[_MAX_FILES] = {
         0, /* close function */
         &_rxtxioctl,
         &__dummy_flush, /* flush function */
+        0, /* lseek */
+        0, 0, /* pointer cache */
     },
     /* stderr */
     {
@@ -86,6 +90,8 @@ static vfs_file_t __filetab[_MAX_FILES] = {
         0, /* close function */
         &_rxtxioctl,
         &__dummy_flush, /* flush function */
+        0, /* lseek */
+        0, 0, /* pointer cache */
     },
 };
 

include/libsys/fmt.c

@@ -909,13 +909,19 @@ TxFunc _gettxfunc(unsigned h) {
     vfs_file_t *v;
     v = __getftab(h);
     if (!v || !v->state) return 0;
-    return (TxFunc)&v->putchar;
+    if (!v->putchar_ptr) {
+        v->putchar_ptr = &v->putchar;
+    }
+    return (TxFunc)v->putchar_ptr;
 }
 RxFunc _getrxfunc(unsigned h) {
     vfs_file_t *v;
     v = __getftab(h);
     if (!v || !v->state) return 0;
-    return (RxFunc)&v->getchar;
+    if (!v->getchar_ptr) {
+        v->getchar_ptr = &v->getchar;
+    }
+    return (RxFunc)v->getchar_ptr;
 }
 static int *_getiolock(unsigned h) {
     vfs_file_t *v;

include/sys/types.h

@@ -62,6 +62,10 @@ struct s_vfs_file_t {
     /* internal functions for formatting routines */
     int putchar(int c) __fromfile("libsys/vfs.c");
     int getchar(void)  __fromfile("libsys/vfs.c");
+
+    /* cache for pointers of the above functions */
+    int (*putchar_ptr)(int c);
+    int (*getchar_ptr)(void);
 };
 
 typedef int (*putcfunc_t)(int c, vfs_file_t *fil);