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ORCALib
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Allow writing immediately after reading to EOF. 

This should be allowed (for read/write files), but it was leading to errors, both because fputc would error out if the EOF flag was set and because the FILE record was not fully reset from its "reading" state. In particular, the _IOREAD flag and the current buffer position pointer need to be reset.

Here is a program that demonstrates the problem:

#include <stdio.h>
int main(void) {
        FILE *f = fopen("somefile","r+");
        if (!f) return 0;
        while (!feof(f)) fgetc(f); /* or: fgetc then fread */
        if (fputc('X', f) == EOF)
                puts("fputc error");
}
This commit is contained in:
Stephen Heumann 2022-07-03 18:51:38 -05:00
parent c877c74b92
commit ef63f26c4f
1 changed files with 47 additions and 22 deletions
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69
stdio.asm
View File

@ -486,7 +486,7 @@ gc1 ph4 <stream else flag the error
jsr ~ioerror
lda #EOF
sta c
brl gc9
brl gc10
gc2 ldy #FILE_flag if the file is not read enabled then
lda [stream],Y
@ -535,6 +535,8 @@ gc4 ldy #FILE_file set the file reference number
ldy #FILE_flag
cmp #$4C if it was eof then
bne gc5
jsr endreads end reading state
ldy #FILE_flag
lda #_IOEOF set the EOF flag
bra gc6 else
gc5 lda #_IOERR set the error flag
@ -542,7 +544,7 @@ gc6 ora [stream],Y
sta [stream],Y
lda #EOF return EOF
sta c
brl gc9
brl gc10
gc7 ldy #FILE_flag we're done if the read is unbuffered
lda [stream],Y
@ -558,18 +560,7 @@ gc7 ldy #FILE_flag we're done if the read is unbuffered
lda rdDataBuffer+2
adc rdTransferCount+2
sta [stream],Y
ldy #FILE_base reset the file pointer
lda [stream],Y
tax
iny
iny
lda [stream],Y
ldy #FILE_ptr+2
sta [stream],Y
dey
dey
txa
sta [stream],Y
jsr resetptr reset the file pointer
ldy #FILE_cnt set the # chars in the buffer
lda rdTransferCount
sta [stream],Y
@ -619,10 +610,7 @@ gc8a ldy #FILE_flag if the file is read/write
iny
ora [stream],Y
bne gc9
ldy #FILE_flag note that no chars are left
lda [stream],Y
eor #_IOREAD
sta [stream],Y
jsr endreads end reading state
gc9 lda c if c = \r then
cmp #13
@ -637,6 +625,28 @@ gc9 lda c if c = \r then
gc10 plb
creturn 2:c
;
; Local subroutine - end "reading" state to prepare for possible writes
;
endreads ldy #FILE_flag if the file is read/write
lda [stream],Y
bit #_IORW
beq resetptr
and #$FFFF-_IOREAD end reading state
sta [stream],Y
resetptr ldy #FILE_base reset the file pointer (alt entry point)
lda [stream],Y
tax
iny
iny
lda [stream],Y
ldy #FILE_ptr+2
sta [stream],Y
dey
dey
txa
sta [stream],Y
rts
;
; Local data
;
rd dc i'4' parameter block for OSRead
@ -1401,9 +1411,9 @@ p equ 1 work pointer
ph4 <stream verify that stream exists
jsl ~VerifyStream
bcs lb0
ldy #FILE_flag quit with error if the end of file
lda [stream],Y has been reached or an error has been
and #_IOEOF+_IOERR encountered
ldy #FILE_flag quit with error if an error has been
lda [stream],Y encountered
and #_IOERR
beq lb1
lb0 lda #EOF
sta c
@ -1738,9 +1748,24 @@ extraCount ds 4 # characters read from putback or buffer
;
; Set the EOF flag
;
SetEOF ldy #FILE_flag set the eof flag
SetEOF ldy #FILE_flag set the eof flag
lda [stream],Y
ora #_IOEOF
bit #_IORW if file is read/write
beq se1
and #$FFFF-_IOREAD turn off the read flag
se1 sta [stream],Y
ldy #FILE_base reset ptr to prepare for possible writes
lda [stream],Y
tax
iny
iny
lda [stream],Y
ldy #FILE_ptr+2
sta [stream],Y
dey
dey
txa
sta [stream],Y
rts
end