Adds fread(), fseek()

src/constants/file.asm

@@ -75,3 +75,7 @@ section .rodata
 	S_IFIFO			equ	0010000q ; FIFO
 	S_IFLNK			equ	0120000q ; Symbolic link
 	S_IFSOCK		equ	0140000q ; Socket
+	; Seek options
+	SEEK_SET		equ	0
+	SEEK_CUR		equ	1
+	SEEK_END		equ	2

src/constants/syscalls.asm

@@ -6,6 +6,7 @@ section .rodata
 	;NR_stat		equ	4
 	NR_fstat		equ	5
 	NR_lstat		equ	6
+	NR_lseek		equ	8
 	NR_exit			equ	60
 	NR_creat		equ	85
 	NR_umask		equ	95

src/file.asm

@@ -14,6 +14,8 @@ section .text
 	global	fclose
 	global	fexist
 	global	fwrite
+	global	fread
+	global	fseek
 
 ;----- stat(*file[], *statBuffer[]) -----;
 ; Gets information from a file, stores it into statBuffer[]
@@ -217,20 +219,19 @@ fexist:
 
 ;--- fwrite(*filePointer, *data[], ...) -----;
 ; Writes data to given file. Allows format specifiers and variable arguments (see `__INTERNAL_fmt` for supported specifiers)
-; Return value: Length of given string(data[]), 0 if nothing was written (eg invalid file or file not writable, or data[] is empty)
+; Return value: Length of given string(data[]), 0 if nothing was written or -errno if an error occured
 ; Used registers:
 ;	rax*	(ret)
 ;	rdi	(arg) Pointer to file
 ;	rsi	(arg) Data to write
 fwrite:
-	push	rbp
-	mov	rbp, rsp
 	cmp	rdi, 2
 	jg	.cnt
-	xor	rax, rax
+	mov	rax, -EBADF
-	leave
 	ret
 	.cnt:
+	push	rbp
+	mov	rbp, rsp
 	mov	rax, rdi
 	mov	rdi, rsi
 	mov	rsi, rdx
@@ -241,3 +242,58 @@ fwrite:
 	call	__INTERNAL_fmt
 	leave
 	ret
+
+;--- fread(*filePointer, *buff[], maxLength) ---;
+; Reads data from given file.
+; Return value: Amount of read characters or -errno if an error occured
+; Used registers:
+;	rax*	(ret)
+;	rdi*	(arg) Pointer to file
+;	rsi	(arg) Pointer to buff[] (where to store read data)
+;	rdx	(arg) Size of buff[]
+fread:
+	cmp	rdi, 2
+	jg	.cnt
+	mov	rax, -EBADF
+	ret
+	.cnt:
+	sub	rsp, SIZE_QWORD
+	mov	rax, NR_read
+	syscall
+	cmp	rax, rdx
+	je	.subOne
+	jmp	.addAll
+	.subOne:
+	add	rsi, rax
+	dec	rsi
+	jmp	.addEOS
+	.addAll:
+	add	rsi, rax
+	.addEOS:
+	mov	byte [rsi], EOS
+	.quit:
+	add	rsp, SIZE_QWORD
+	ret
+
+;--- fseek(*filePointer, mode, offset) ---;
+; Sets pointer in file. Mode is SEEK_SET, SEEK_CUR or SEEK_END.
+; Return value: On succes returns the resulting offset location as measured in bytes from the beginning of the file. On error, -errno
+; Used registers:
+;	rax*	(ret)
+;	rdi	(arg) Pointer to file
+;	rsi 	(arg) Seek mode
+;	rdx	(arg) Pointer offset
+fseek:
+	cmp	rdi, 2
+	jg	.cnt
+	mov	rax, -EBADF
+	ret
+	.cnt:
+	sub	rsp, SIZE_QWORD
+	mov	rax, rsi
+	mov	rsi, rdx
+	mov	rdx, rax
+	mov	rax, NR_lseek
+	syscall
+	add	rsp, SIZE_QWORD
+	ret

src/tests.asm

@@ -96,6 +96,8 @@ extern	stat
 extern	lstat
 extern	fgettype
 extern	fgetmod
+extern	fread
+extern	fseek
 
 section .rodata
 	;;;
@@ -136,6 +138,8 @@ section .rodata
 	;file.asm
 	TEST_fopen		equ	1 ;Includes fclose
 	TEST_fwrite		equ	1
+	TEST_fread		equ	1
+	TEST_fseek		equ	1
 	TEST_stat		equ	1
 	TEST_lstat		equ	1
 	TEST_fgettype		equ	1
@@ -349,6 +353,14 @@ section .rodata
 	addTest(fwrite3, "fwrite(fp1, 'Howdy environment!') //mode 'w'")
 	addTest(fwrite4, "fwrite(fp1, ''%c%c%c%c%c%c%c%c\n'', 'H', 'e', 'l', 'l', 'o', '!', '?', '!')")
 	fwriteStr1	db	"%c%c%c%c%c%c%c%c\n",EOS
+	;fread()
+	addTestHeader(_fread, "fread")
+	addTest(fread1, "fread(fp1, strBuff1, 64)")
+	;fseek()
+	addTestHeader(_fseek, "fseek")
+	addTest(fseek1, "fseek(fp1, SEEK_SET, 5)")
+	addTest(fseek2, "fseek(fp1, SEEK_CUR, -1)")
+	addTest(fseek3, "fseek(fp1, SEEK_SET, 0)")
 	;stat()
 	addTestHeader(_stat, "stat")
 	addTest(stat1, "stat('tests', statBuff1)")
@@ -1288,6 +1300,91 @@ _start:
 	call	fclose
 %endif
 
+;--- fread()
+%if TEST_fread
+	printTestHeader(_fread)
+	mov	rdi, [fp1]
+	call	fclose
+	lea	rdi, [rel file1]
+	mov	rsi, 'r'
+	call	fopen
+	assert_neq(0)
+	mov	[fp1], rax
+
+	printTest(fread1)
+	mov	rdi, [fp1]
+	lea	rsi, [rel strBuff1]
+	mov	rdx, 64
+	call	fread
+	assert_more_eq(1)
+	lea	rdi, [rel strBuff1]
+	call	puts
+
+	mov	rdi, [fp1]
+	call	fclose
+%endif
+
+;--- fseek()
+%if TEST_fseek
+	%macro fseek_relptr 1
+	%endmacro
+	%macro fseek_readput 0
+	mov	rdi, [fp1]
+	lea	rsi, [rel strBuff1]
+	mov	rdx, 64
+	call	fread
+	lea	rdi, [rel strBuff1]
+	call	puts
+	%endmacro
+	printTestHeader(_fseek)
+
+	lea	rdi, [rel file1]
+	mov	rsi, 'r'
+	call	fopen
+	mov	[fp1], rax
+
+	; TEST 1: fseek(fp1, SEEK_SET, 5)
+	printTest(fseek1)
+	mov	rdi, [fp1]
+	mov	rsi, SEEK_CUR
+	mov	rdx, 5
+	call	fseek
+	assert_eq(5)
+	fseek_readput
+
+	; TEST 2: fseek(fp1, SEEK_CUR, -1)
+	printTest(fseek2)
+	mov	rdi, [fp1]
+	mov	rsi, SEEK_SET
+	mov	rdx, 5
+	call	fseek
+	;^ fseek_readput (fread) modified pointer, so restore it to result of test 1
+	mov	rdi, [fp1]
+	mov	rsi, SEEK_CUR
+	mov	rdx, -1
+	call	fseek
+	assert_eq(4)
+	fseek_readput
+	; FAIL. Returned is 26 (which is length of the file)
+	; My best guess is -1 is treated as unsigned. However, according to man 2 lseek:
+	;	The off_t data type is a signed integer data type
+	; ( offset in rdx is supposed to be (off_t) offset )
+	; If it turns out unsigned after all, I'll have to manually get current location of pointer (call NR_lseek with SEEK_CUR and offset 0; returned value is current location)
+	; ... and then substract given argument from that
+
+	; TEST 3: fseek(fp1, SEEK_SET, 0)
+	printTest(fseek3)
+	mov	rdi, [fp1]
+	mov	rsi, SEEK_SET
+	xor	rdx, rdx
+	call	fseek
+	assert_eq(0)
+	fseek_readput
+
+	mov	rdi, [fp1]
+	call	fclose
+%endif
+
 ;--- stat()
 %if TEST_stat
 	printTestHeader(_stat)