From 40d9f3eed513f4263f93aa6400acae931083a183 Mon Sep 17 00:00:00 2001
From: Colin Leroy-Mira <colin@colino.net>
Date: Sun, 10 Nov 2024 13:38:35 +0100
Subject: [PATCH] Apple2: Provide a way to get directory file count

The information is available in the directory key block.
Providing it to the user as soon as opendir() is done
can save them costly code.
---
 doc/apple2.sgml                |  1 +
 doc/apple2enh.sgml             |  1 +
 doc/funcref.sgml               | 21 +++++++++++++++++++++
 include/apple2.h               |  5 +++++
 include/dirent.h               |  2 --
 libsrc/apple2/dir.h            |  1 +
 libsrc/apple2/dir.inc          |  2 +-
 libsrc/apple2/dir_file_count.s | 24 ++++++++++++++++++++++++
 libsrc/apple2/opendir.s        | 21 ++++++++++-----------
 9 files changed, 64 insertions(+), 14 deletions(-)
 create mode 100644 libsrc/apple2/dir_file_count.s

diff --git a/doc/apple2.sgml b/doc/apple2.sgml
index c0255c4f7..c6b2fe8eb 100644
--- a/doc/apple2.sgml
+++ b/doc/apple2.sgml
@@ -332,6 +332,7 @@ usage.
 <item>_datetime
 <item>allow_lowercase
 <item>beep
+<item>dir_file_count
 <item>get_ostype
 <item>gmtime_dt
 <item>mktime_dt
diff --git a/doc/apple2enh.sgml b/doc/apple2enh.sgml
index 9c46bd4fb..ea950fa26 100644
--- a/doc/apple2enh.sgml
+++ b/doc/apple2enh.sgml
@@ -332,6 +332,7 @@ usage.
 <item>_filetype
 <item>_datetime
 <item>beep
+<item>dir_file_count
 <item>get_ostype
 <item>gmtime_dt
 <item>mktime_dt
diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index ea2350aad..7664739fe 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -97,6 +97,7 @@ function.
 <item>_dos_type
 <item>allow_lowercase
 <item><ref id="beep" name="beep">
+<item><ref id="dir_file_count" name="dir_file_count">
 <item><ref id="get_ostype" name="get_ostype">
 <item><ref id="gmtime_dt" name="gmtime_dt">
 <item><ref id="mktime_dt" name="mktime_dt">
@@ -109,6 +110,7 @@ function.
 <itemize>
 <item>_dos_type
 <item><ref id="beep" name="beep">
+<item><ref id="dir_file_count" name="dir_file_count">
 <item><ref id="get_ostype" name="get_ostype">
 <item><ref id="gmtime_dt" name="gmtime_dt">
 <item><ref id="mktime_dt" name="mktime_dt">
@@ -3524,6 +3526,25 @@ used in presence of a prototype.
 </quote>
 
 
+<sect1>dir_file_count<label id="dir_file_count"><p>
+
+<quote>
+<descrip>
+<tag/Function/Returns the number of files in the directory.
+<tag/Header/<tt/<ref id="apple2.h" name="apple2.h">/
+<tag/Declaration/<tt/unsigned int __fastcall__ dir_file_count(DIR *dir);/
+<tag/Description/<tt/dir_file_count/ is machine dependent and does not exist for
+all supported targets. If it exists, it returns the number of active
+(non-deleted) files in the directory.
+<tag/Notes/<itemize>
+<item>The function does not exist on all platforms.
+</itemize>
+<tag/Availability/cc65 (not all platforms)
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>div<label id="div"><p>
 
 <quote>
diff --git a/include/apple2.h b/include/apple2.h
index 1a840be6e..358d44ac4 100644
--- a/include/apple2.h
+++ b/include/apple2.h
@@ -232,6 +232,11 @@ struct tm* __fastcall__ gmtime_dt (const struct datetime* dt);
 time_t __fastcall__ mktime_dt (const struct datetime* dt);
 /* Converts a ProDOS date/time structure to a time_t UNIX timestamp */
 
+typedef struct DIR DIR;
+
+unsigned int __fastcall__ dir_file_count(DIR *dir);
+/* Returns the number of active files in a ProDOS directory */
+
 #if !defined(__APPLE2ENH__)
 unsigned char __fastcall__ allow_lowercase (unsigned char onoff);
 /* If onoff is 0, lowercase characters printed to the screen via STDIO and
diff --git a/include/dirent.h b/include/dirent.h
index b95646833..60982ba05 100644
--- a/include/dirent.h
+++ b/include/dirent.h
@@ -147,7 +147,5 @@ void __fastcall__ seekdir (DIR* dir, long offs);
 
 void __fastcall__ rewinddir (DIR* dir);
 
-
-
 /* End of dirent.h */
 #endif
diff --git a/libsrc/apple2/dir.h b/libsrc/apple2/dir.h
index 369080c47..ed44f08c6 100644
--- a/libsrc/apple2/dir.h
+++ b/libsrc/apple2/dir.h
@@ -45,6 +45,7 @@ struct DIR {
     int           fd;
     unsigned char entry_length;
     unsigned char entries_per_block;
+    unsigned int  file_count;
     unsigned char current_entry;
     union {
         unsigned char bytes[512];
diff --git a/libsrc/apple2/dir.inc b/libsrc/apple2/dir.inc
index afad44eb7..545ae003b 100644
--- a/libsrc/apple2/dir.inc
+++ b/libsrc/apple2/dir.inc
@@ -2,8 +2,8 @@
         FD                .word
         ENTRY_LENGTH      .byte
         ENTRIES_PER_BLOCK .byte
+        FILE_COUNT        .word
         CURRENT_ENTRY     .byte
-
         .union
                 BYTES               .byte 512
                 .struct CONTENT
diff --git a/libsrc/apple2/dir_file_count.s b/libsrc/apple2/dir_file_count.s
new file mode 100644
index 000000000..aa864e32a
--- /dev/null
+++ b/libsrc/apple2/dir_file_count.s
@@ -0,0 +1,24 @@
+;
+; Colin Leroy-Mira <colin@colino.net>, 2024
+;
+; unsigned int __fastcall__ dir_file_count(DIR *dir);
+;
+
+        .export   _dir_file_count
+
+        .importzp ptr1
+
+        .include  "apple2.inc"
+        .include  "dir.inc"
+
+.proc _dir_file_count
+        sta       ptr1
+        stx       ptr1+1
+
+        ldy       #DIR::FILE_COUNT + 1
+        lda       (ptr1),y
+        tax
+        dey
+        lda       (ptr1),y
+        rts
+.endproc
diff --git a/libsrc/apple2/opendir.s b/libsrc/apple2/opendir.s
index b75b83636..38110b680 100644
--- a/libsrc/apple2/opendir.s
+++ b/libsrc/apple2/opendir.s
@@ -128,24 +128,23 @@
         ; Read succeeded, populate dir struct
         jsr       popptr1     ; Restore our dir pointer
 
-        ldy       #$24 + DIR::BYTES
-        lda       (ptr1),y    ; ENTRIES_PER_BLOCK
-        pha                   ; Back it up
-
+        ; Get file_count to entry_length from block
+        ldy       #$26 + DIR::BYTES
+:       lda       (ptr1),y
+        pha
         dey
-        lda       (ptr1),y    ; ENTRY_LENGTH
+        cpy       #$23 + DIR::BYTES - 1
+        bne       :-
 
+        ; Set entry_length to file_count in struct
         ldy       #DIR::ENTRY_LENGTH
+:       pla
         sta       (ptr1),y
-
-        pla
-        .assert   DIR::ENTRIES_PER_BLOCK = DIR::ENTRY_LENGTH + 1, error
         iny
-        sta       (ptr1),y
+        cpy       #DIR::CURRENT_ENTRY
+        bne       :-
 
         ; Skip directory header entry
-        .assert   DIR::CURRENT_ENTRY = DIR::ENTRIES_PER_BLOCK + 1, error
-        iny
         lda       #$01
         sta       (ptr1),y