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New function _dirskip that allows to skip an amount of bytes from the
directory with error check. git-svn-id: svn://svn.cc65.org/cc65/trunk@5668 b7a2c559-68d2-44c3-8de9-860c34a00d81
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@ -65,6 +65,7 @@ S_OBJS = c_acptr.o \
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closedir.o \
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ctype.o \
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cvline.o \
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dir.o \
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diskcmd.o \
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exehdr.o \
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filedes.o \
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@ -24,6 +24,22 @@ struct DIR {
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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unsigned char __fastcall__ _dirskip (unsigned char count, struct DIR* dir);
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/* Skip bytes from the directory and make sure, errno is set if this isn't
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* possible. Return true if anything is ok and false otherwise. For
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* simplicity we assume that read will never return less than count if there
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* is no error and end-of-file is not reached.
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* Note: count must not be more than 254.
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*/
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/* End of dir.h */
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#endif
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@ -23,5 +23,5 @@
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.global _readdir
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.global _telldir
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.global _rewinddir
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.global __dirskip
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92
libsrc/cbm/dir.s
Normal file
92
libsrc/cbm/dir.s
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@ -0,0 +1,92 @@
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;
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; Ullrich von Bassewitz, 2012-06-01
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;
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; unsigned char __fastcall__ _dirskip (unsigned char count, struct DIR* dir);
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; /* Skip bytes from the directory and make sure, errno is set if this isn't
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; * possible. Return true if anything is ok and false otherwise. For
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; * simplicity we assume that read will never return less than count if there
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; * is no error and end-of-file is not reached.
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; * Note: count must not be more than 254.
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; */
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;
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.include "dir.inc"
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.include "errno.inc"
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.include "zeropage.inc"
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.import _read
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.import pushax, pushptr1idx
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.import subysp, addysp1
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.proc __dirskip
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sta ptr1
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stx ptr1+1 ; Save dir
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; Get count and allocate space on the stack
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ldy #0
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lda (sp),y
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pha
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tay
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jsr subysp
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; Save current value of sp
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lda sp
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pha
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lda sp+1
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pha
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; Push dir->fd
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ldy #DIR::fd+1
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jsr pushptr1idx
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; Push pointer to buffer
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pla
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tax
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pla
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jsr pushax
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; Load count and call read
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pla
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pha
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ldx #0
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jsr _read
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; Check for errors. In case of errors, errno is already set.
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cpx #$FF
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bne L2
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; read() returned an error
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pla ; Count
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tay
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lda #0
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tax
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L1: jmp addysp1 ; Drop buffer plus count
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; read() was successful, check number of bytes read. We assume that read will
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; not return more than count, so X is zero if we come here.
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L2: sta tmp1
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pla ; count
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tay
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cmp tmp1
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beq L1 ; Drop variables, return count
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; Didn't read enough bytes. This is an error for us, but errno is not set
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lda #<EIO
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sta __errno
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stx __errno+1
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txa ; A=X=0
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beq L1 ; Branch always
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.endproc
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@ -1,3 +1,7 @@
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/*
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* Ullrich von Bassewitz, 2012-05-30. Based on code by Groepaz.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <dirent.h>
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@ -10,10 +14,8 @@
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DIR* __fastcall__ opendir (const char*)
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{
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unsigned char buffer[8+16+1+7];
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int count;
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DIR d;
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DIR* dir = 0;
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DIR d;
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/* Setup file name and offset */
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d.name[0] = '$';
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@ -25,8 +27,7 @@ DIR* __fastcall__ opendir (const char*)
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if (d.fd >= 0) {
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/* Skip the disk header */
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count = read (d.fd, buffer, sizeof (buffer));
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if (count == sizeof (buffer)) {
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if (_dirskip (32, &d)) {
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/* Allocate memory for the DIR structure returned */
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dir = malloc (sizeof (*dir));
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@ -38,9 +39,6 @@ DIR* __fastcall__ opendir (const char*)
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/* Set an appropriate error code */
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errno = ENOMEM;
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}
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} else if (count >= 0) {
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/* Short read - need to set an error code */
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errno = EIO;
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}
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}
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