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Implement special read function that sets errno in case of a short read. Drop
_dirskip in favour of the new function. git-svn-id: svn://svn.cc65.org/cc65/trunk@5672 b7a2c559-68d2-44c3-8de9-860c34a00d81
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@ -30,12 +30,16 @@ struct DIR {
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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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unsigned char __fastcall__ _dirread (DIR* dir, void* buf, unsigned char count);
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/* Read characters from the directory into the supplied buffer. Makes sure,
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* errno is set in case of a short read. Return true if the read was
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* successful and false otherwise.
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*/
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unsigned char __fastcall__ _dirread1 (DIR* dir, void* buf);
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/* Read one byte from the directory into the supplied buffer. Makes sure,
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* errno is set in case of a short read. Return true if the read was
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* successful and false otherwise.
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*/
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@ -21,7 +21,10 @@
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.global _opendir
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.global _closedir
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.global _readdir
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.global _telldir
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.global _rewinddir
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; .global _telldir
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; .global _rewinddir
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.global __dirread
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.global __dirread1
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.global __dirskip
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113
libsrc/cbm/dir.s
113
libsrc/cbm/dir.s
@ -1,92 +1,99 @@
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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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; Helper functions for open-/read-/closedir
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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 pushax
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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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;---------------------------------------------------------------------------
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;
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; unsigned char __fastcall__ _dirread1 (DIR* dir, void* buf);
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; /* Read one byte from the directory into the supplied buffer. Makes sure,
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; * errno is set in case of a short read. Return true if the read was
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; * successful and false otherwise.
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; */
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sta ptr1
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stx ptr1+1 ; Save dir
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__dirread1:
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; Get count and allocate space on the stack
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jsr pushax ; Push buf
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lda #1 ; Load count = 1
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ldy #0
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; Run directly into __dirread
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;---------------------------------------------------------------------------
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;
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; unsigned char __fastcall__ _dirread (DIR* dir, void* buf, unsigned char count);
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; /* Read characters from the directory into the supplied buffer. Makes sure,
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; * errno is set in case of a short read. Return true if the read was
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; * successful and false otherwise.
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; */
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__dirread:
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; Save count
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pha
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; Replace dir by dir->fd
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ldy #2
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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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sta ptr1
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iny
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lda (sp),y
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sta ptr1+1
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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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lda (ptr1),y
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pha
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dey
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lda (ptr1),y
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ldy #2
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sta (sp),y
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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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iny
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sta (sp),y
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; Load count and call read
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; Get count, save it again, clear the high byte and call read(). By the
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; previous actions, the stack frame is as read() needs it, and read() will
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; also drop it.
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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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; Check for errors.
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cpx #$FF
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bne L2
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bne L3
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; read() returned an error
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; read() returned an error, so errno is already set
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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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pla ; Drop count
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inx ; X = 0
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L1: txa ; Return zero
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L2: rts
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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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L3: sta tmp1 ; Save returned count
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pla ; Our count
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cmp tmp1
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beq L1 ; Drop variables, return count
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beq L2 ; Ok, 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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stx __errno+1 ; X is zero
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bne L1 ; Branch always
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.endproc
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@ -13,7 +13,8 @@
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DIR* __fastcall__ opendir (const char*)
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{
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{
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unsigned char buf[32];
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DIR* dir = 0;
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DIR d;
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@ -27,7 +28,7 @@ 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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if (_dirskip (32, &d)) {
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if (_dirread (&d, buf, 32)) {
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/* Allocate memory for the DIR structure returned */
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dir = malloc (sizeof (*dir));
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@ -18,36 +18,34 @@
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struct dirent* __fastcall__ readdir (register DIR* dir)
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{
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static struct dirent entry;
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register unsigned char* b;
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register unsigned char i;
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unsigned char count;
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unsigned char j;
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register unsigned char count;
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unsigned char s;
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unsigned char j;
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unsigned char buffer[0x40];
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static struct dirent entry;
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/* Remember the directory offset for this entry */
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entry.d_off = dir->off;
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/* Skip the basic line-link */
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if (!_dirskip (2, dir)) {
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if (!_dirread (dir, buffer, 2)) {
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/* errno already set */
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goto exit;
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goto exitpoint;
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}
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dir->off += 2;
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/* Read the number of blocks */
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if (read (dir->fd, &entry.d_blocks, sizeof (entry.d_blocks)) !=
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sizeof (entry.d_blocks)) {
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goto error;
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if (!_dirread (dir, &entry.d_blocks, sizeof (entry.d_blocks))) {
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goto exitpoint;
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}
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/* Read the next file entry into the buffer */
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for (count = 0, b = buffer; count < sizeof (buffer); ++count, ++b) {
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if (read (dir->fd, b, 1) != 1) {
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/* ### Check for EOF */
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goto error;
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if (!_dirread1 (dir, b)) {
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goto exitpoint;
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}
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if (*b == '\0') {
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break;
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@ -59,7 +57,7 @@ struct dirent* __fastcall__ readdir (register DIR* dir)
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* called again, read until end of directory.
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*/
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if (count > 0 && buffer[0] == 'b') {
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while (read (dir->fd, buffer, 1) == 1) ;
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while (_dirread1 (dir, buffer)) ;
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return 0;
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}
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@ -120,10 +118,9 @@ struct dirent* __fastcall__ readdir (register DIR* dir)
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++b;
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}
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/* Something went wrong - terminating quote not found */
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error:
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/* Something went wrong when parsing the directory entry */
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_errno = EIO;
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exit:
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exitpoint:
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return 0;
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}
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