refactor to implement arguments

.gitignore

@@ -1,2 +1,2 @@
-main.obj
-sha256sum.exe
+*.obj
+*.exe

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "files.associations": {
+        "sha256.h": "c",
+        "wchar.h": "c",
+        "args.h": "c"
+    }
+}

Makefile

@@ -8,7 +8,7 @@ CFLAGS = /W4 /MD /O2
 OUTFILE = sha256sum.exe
 
 # Source files
-SOURCES = main.c
+SOURCES = main.c args.c sha256.c
 
 # Object files (one per source file)
 OBJECTS = $(SOURCES:.c=.obj)

Makefile.tests

@@ -0,0 +1,32 @@
+# Compiler
+CC = cl
+
+# Flags for the compiler
+CFLAGS = /W4 /MD /O2
+
+# Name of the final executable
+OUTFILE = tests.exe
+
+# Source files
+SOURCES = tests.c args.c
+
+# Object files (one per source file)
+OBJECTS = $(SOURCES:.c=.obj)
+
+# Default target
+all: $(OUTFILE)
+
+# Linking rule
+$(OUTFILE): $(OBJECTS)
+    $(CC) $(CFLAGS) /Fe$@ $(OBJECTS) /link
+
+# Compilation rule
+.c.obj:
+    $(CC) $(CFLAGS) /c $< /Fo$@
+
+# Clean rule
+clean:
+    del *.obj $(OUTFILE)
+
+# Phony targets
+.PHONY: all clean

args.c

@@ -0,0 +1,40 @@
+#include "args.h"
+
+errno_t parse_args(int argc, wchar_t *argv[], wchar_t **out_shasums_file)
+{
+  if (argc < 2)
+  {
+    usage(argv[0], L"missing parameter");
+    return ARGS_MISSING_PARAMETER;
+  }
+
+  for (int i = 0; i < argc; ++i)
+  {
+    if (wcscmp(argv[i], L"-c") == 0)
+    {
+      // check if there is another argument after -c
+      if (i + 1 < argc)
+      {
+        *out_shasums_file = argv[i + 1];
+        ++i; // skip next argument since we used it here
+      }
+      else
+      {
+        usage(argv[0], L"");
+        return ARGS_MISSING_SHASUMS_FILE;
+      }
+    }
+  }
+
+  return OK;
+}
+
+void usage(wchar_t *prog, wchar_t *message)
+{
+  if (NULL != message)
+  {
+    fwprintf(stderr, L"%ls\n", message);
+  }
+
+  wprintf(L"Usage: %ls [-c sha256sums_file] [file...]\n", prog);
+}

args.h

@@ -0,0 +1,9 @@
+#pragma once
+#include <wchar.h>
+
+#define OK 0
+#define ARGS_MISSING_PARAMETER 1
+#define ARGS_MISSING_SHASUMS_FILE 2
+
+errno_t parse_args(int argc, wchar_t *argv[], wchar_t **out_shasums_file);
+void usage(wchar_t *prog, wchar_t *message);

main.c

@@ -1,189 +1,28 @@
-#include <windows.h>
-#include <stdio.h>
-#include <bcrypt.h>
+#include "args.h"
+#include "sha256.h"
 
-#pragma comment(lib, "bcrypt.lib")
-
-#define NT_SUCCESS(Status) (((NTSTATUS)(Status)) >= 0)
-#define STATUS_UNSUCCESSFUL ((NTSTATUS)0xC0000001L)
-#define SET_FAILURE_AND_CLEANUP do { \
-    failure = TRUE;                       \
-    goto Cleanup;                         \
-} while(0)
-
-int __cdecl wmain(int argc, wchar_t *argv[])
+int wmain(int argc, wchar_t *argv[])
 {
-  BOOL failure = FALSE;
-  HANDLE hFile;
-  DWORD dwBytesRead;
-  BYTE buffer[1024] = {0};
+  wchar_t *shasums_file = NULL;
 
-  BCRYPT_ALG_HANDLE hAlg = NULL;
-  BCRYPT_HASH_HANDLE hHash = NULL;
-  NTSTATUS status = STATUS_UNSUCCESSFUL;
-  DWORD cbData = 0,
-        cbHash = 0,
-        cbHashObject = 0;
-  PBYTE pbHashObject = NULL;
-  PBYTE pbHash = NULL;
-
-  // read args
-  if (argc < 2)
+  errno_t parse_result = parse_args(argc, argv, &shasums_file);
+  if (parse_result != OK)
   {
-    wprintf(L"missing file parameter\n");
-    wprintf(L"usage: %ls <filename>\n", argv[0]);
     return 1;
   }
 
-  // open file
-  hFile = CreateFileW(argv[1],               // File name
-                      GENERIC_READ,          // Open for reading
-                      0,                     // No sharing
-                      NULL,                  // Default security
-                      OPEN_EXISTING,         // Existing file only
-                      FILE_ATTRIBUTE_NORMAL, // Normal file
-                      NULL);
-  if (hFile == INVALID_HANDLE_VALUE)
-  {
-    wprintf(L"open file failed: %d\n", GetLastError());
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // open an algorithm handle
-  if (!NT_SUCCESS(status = BCryptOpenAlgorithmProvider(
-                      &hAlg,
-                      BCRYPT_SHA256_ALGORITHM,
-                      NULL,
-                      0)))
-  {
-    wprintf(L"open an algorithm handle failed: %x\n", status);
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // calculate the size of the buffer to hold the hash object
-  if (!NT_SUCCESS(status = BCryptGetProperty(
-                      hAlg,
-                      BCRYPT_OBJECT_LENGTH,
-                      (PBYTE)&cbHashObject,
-                      sizeof(DWORD),
-                      &cbData,
-                      0)))
-  {
-    wprintf(L"hash buffer size allocation failed, err: %x\n", status);
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // allocate the hash object on the heap
-  pbHashObject = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbHashObject);
-  if (NULL == pbHashObject)
-  {
-    wprintf(L"memory allocation for hash object failed\n");
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // calculate the length of the hash
-  if (!NT_SUCCESS(status = BCryptGetProperty(
-                      hAlg,
-                      BCRYPT_HASH_LENGTH,
-                      (PBYTE)&cbHash,
-                      sizeof(DWORD),
-                      &cbData,
-                      0)))
+  // just print checksum
+  if (shasums_file == NULL)
   {
-    wprintf(L"hash length calculation failed: %x\n", status);
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // allocate the hash buffer on the heap
-  pbHash = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbHash);
-  if (NULL == pbHash)
-  {
-    wprintf(L"memory allocation for hash buffer failed\n");
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  // create a hash
-  if (!NT_SUCCESS(status = BCryptCreateHash(
-                      hAlg,
-                      &hHash,
-                      pbHashObject,
-                      cbHashObject,
-                      NULL,
-                      0,
-                      0)))
-  {
-    wprintf(L"hash creation failed: %x\n", status);
-    SET_FAILURE_AND_CLEANUP;
-  }
-
-  while (TRUE)
-  {
-    if (!ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL))
+    wchar_t *file_hash = calc_hash(argv[1]);
+    if (file_hash != NULL)
     {
-      wprintf(L"read file failed: %d\n", GetLastError());
-      SET_FAILURE_AND_CLEANUP;
-    }
-
-    if (dwBytesRead == 0)
-    {
-      break;
-    }
-
-    // hash some data
-    if (!NT_SUCCESS(status = BCryptHashData(
-                        hHash,
-                        (PBYTE)buffer,
-                        dwBytesRead,
-                        0)))
-    {
-      wprintf(L"data hashing failed: %x\n", status);
-      SET_FAILURE_AND_CLEANUP;
+      wprintf(L"%ls %ls\n", file_hash, argv[1]);
     }
   }
-
-  // close the hash
-  if (!NT_SUCCESS(status = BCryptFinishHash(
-                      hHash,
-                      pbHash,
-                      cbHash,
-                      0)))
+  // check SHASUMS
+  else
   {
-    wprintf(L"hash finalization failed: %x\n", status);
-    SET_FAILURE_AND_CLEANUP;
+    wprintf(L"to be implemented");
   }
-
-  // Output the hash
-  for (DWORD i = 0; i < cbHash; i++)
-  {
-    printf("%02x", pbHash[i]);
-  }
-
-Cleanup:
-
-  if (hFile)
-  {
-    CloseHandle(hFile);
-  }
-
-  if (hAlg)
-  {
-    BCryptCloseAlgorithmProvider(hAlg, 0);
-  }
-
-  if (hHash)
-  {
-    BCryptDestroyHash(hHash);
-  }
-
-  if (pbHashObject)
-  {
-    HeapFree(GetProcessHeap(), 0, pbHashObject);
-  }
-
-  if (pbHash)
-  {
-    HeapFree(GetProcessHeap(), 0, pbHash);
-  }
-
-  return failure;
 }