--- /dev/null
+
+extern printf
+extern malloc
+extern realloc
+extern free
+extern memset
+
+global readFile
+
+section .data
+ wrongfile_str db `unable to open file, error code: %i\n`, 0x00
+
+section .text
+
+; reads file line by line
+; args: filename
+; return:
+; eax - pointer to mem
+; ecx - lines read
+readFile:
+ %define _FILE_NAME 8
+ %define FILE_HANDLE 4
+ %define IS_EOF 8
+ %define LINES_READ 12
+ %define BUF_PTR 16 ; malloced array of strings
+
+ push ebp
+ mov ebp, esp
+
+ ; allocate vars
+ sub esp, 16
+ mov DWORD [ebp-FILE_HANDLE], 0x00
+ mov DWORD [ebp-IS_EOF], 0x00
+ mov DWORD [ebp-LINES_READ], 0x00
+
+ push 0
+ call malloc
+ mov [ebp-BUF_PTR], eax
+
+ ; open existing file
+ mov eax, 5
+ mov ebx, [ebp+_FILE_NAME]
+ mov ecx, 0
+ mov edx, 0777
+ int 0x80
+ mov [ebp-FILE_HANDLE], eax
+
+ ; check if file was open successfully
+ cmp eax, 0
+ jge _readFile_loop
+ push eax
+ push wrongfile_str
+ call printf
+ jmp _readFile_exit
+
+ _readFile_loop:
+
+ ; check if eof was reached
+ cmp DWORD [ebp-IS_EOF], 1
+ je _readFile_exit
+
+ push DWORD [ebp-FILE_HANDLE]
+ call readLine
+
+ mov esi, eax
+ mov [ebp-IS_EOF], ebx
+
+ push esi
+ call printf
+
+ ; make string buffer bigger
+ mov eax, DWORD [ebp-LINES_READ]
+ add eax, 1
+ mov ecx, 4
+ mul ecx
+ push eax
+ push DWORD [ebp-BUF_PTR]
+ call realloc
+ mov DWORD [ebp-BUF_PTR], eax
+
+ ; write string to buffer
+ mov eax, DWORD [ebp-BUF_PTR]
+ mov ecx, 4
+ mul ecx
+ mov eax, esi
+
+ add DWORD [ebp-LINES_READ], 1
+
+ jmp _readFile_loop
+
+ _readFile_exit:
+ ; close file
+ mov eax, 6
+ mov ebx, [ebp-FILE_HANDLE]
+ int 0x80
+
+ mov eax, [ebp-BUF_PTR]
+ mov ecx, [ebp-LINES_READ]
+
+ %undef _FILE_NAME
+ %undef FILE_HANDLE
+ %undef IS_EOF
+ %undef LINES_READ
+ %undef BUF_PTR
+
+ mov esp, ebp
+ pop ebp
+ ret
+
+
+; reads a line until newline character is reached
+; args: file_handle
+; return:
+; eax: location to buffer
+; ebx: contains eof
+readLine:
+ %define _FILE_HANDLE 8
+ %define CHAR_COUNT 4 ; count number of characters read
+ %define BLOCK_COUNT 8 ; number of 64 blocks we've read
+ %define STR_PTR 12 ; malloced buffer to store read string
+
+ push ebp
+ mov ebp, esp
+
+ ; allocate vars
+ sub esp, 12
+ mov DWORD [ebp-CHAR_COUNT], 0x00
+ mov DWORD [ebp-BLOCK_COUNT], 0x00
+
+ push 64
+ call malloc
+ mov [ebp-STR_PTR], eax
+
+ push DWORD [ebp-STR_PTR]
+ push 0x00
+ push 64
+
+ _readLine_loop:
+ ; if buffer is full
+ cmp BYTE [ebp-CHAR_COUNT], 63 ; leave one byte for null byte
+ jne _readLine_notfull
+ jmp _readLine_exit
+
+ _readLine_notfull:
+ ; read a single character
+ mov eax, 3
+ mov ebx, [ebp+_FILE_HANDLE]
+ mov ecx, [ebp-STR_PTR]
+ add ecx, [ebp-CHAR_COUNT]
+ mov edx, 1
+ int 0x80
+
+ ; mov eax, 4
+ ; mov ebx, 1
+ ; mov ecx, [ebp-STR_PTR]
+ ; add ecx, [ebp-CHAR_COUNT]
+ ; mov edx, 1
+ ; int 0x80
+
+ ; check for eof
+ cmp eax, 0 ; eax has zero on eof
+ jne _readLine_not_eof
+ mov ebx, 1
+ jmp _readLine_exit
+ _readLine_not_eof:
+
+ ; check for newline
+ mov eax, [ebp-STR_PTR]
+ add eax, [ebp-CHAR_COUNT]
+ cmp DWORD [eax], 0x0a
+ jne _readLine_not_newline
+ mov ebx, 0
+ jmp _readLine_exit
+ _readLine_not_newline:
+
+ add DWORD [ebp-CHAR_COUNT], 1
+ jmp _readLine_loop
+
+ _readLine_exit:
+
+ mov eax, DWORD [ebp-STR_PTR]
+
+ %undef _FILE_HANDLE
+ %undef CHAR_COUNT
+ %undef BLOCK_COUNT
+ %undef STR_PTR
+
+ mov esp, ebp
+ pop ebp
+ ret
+
