X-Git-Url: https://git.danieliu.xyz/?p=sped.git;a=blobdiff_plain;f=fileutils.asm;fp=fileutils.asm;h=1d96aa05eae9e75b012d83cd66cc094f90113cd3;hp=0000000000000000000000000000000000000000;hb=fb894149783dd18e6ecf1271153193a342e80433;hpb=f4e4f6cbfee907de343ab7a08a90d38b18def0a1

diff --git a/fileutils.asm b/fileutils.asm
new file mode 100644
index 0000000..1d96aa0
--- /dev/null
+++ b/fileutils.asm
@@ -0,0 +1,191 @@
+
+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
+