Merge pull request #787 from DrLynix/compare-files-function

os.comparefiles function

src/host/os_comparefiles.c

@@ -0,0 +1,132 @@
+/**
+ * \file   os_comparefiles.c
+ * \brief  Check if two files are identical.
+ * \author Copyright (c) 2015 Jérôme "Lynix" Leclercq and the Premake project
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "premake.h"
+
+int os_comparefiles(lua_State* L)
+{
+	FILE* firstFile;
+	FILE* secondFile;
+	size_t firstSize;
+	size_t secondSize;
+	size_t count;
+	size_t read;
+	char firstBuffer[4096];
+	char secondBuffer[4096];
+	const char* firstPath = luaL_checkstring(L, 1);
+	const char* secondPath = luaL_checkstring(L, 2);
+
+	#if PLATFORM_WINDOWS
+	wchar_t wide_firstPath[PATH_MAX];
+	if (MultiByteToWideChar(CP_UTF8, 0, firstPath, -1, wide_firstPath, PATH_MAX) == 0)
+	{
+		lua_pushnil(L);
+		lua_pushstring(L, "unable to encode first path");
+		return 2;
+	}
+
+	wchar_t wide_secondPath[PATH_MAX];
+	if (MultiByteToWideChar(CP_UTF8, 0, secondPath, -1, wide_secondPath, PATH_MAX) == 0)
+	{
+		lua_pushnil(L);
+		lua_pushstring(L, "unable to encode second path");
+		return 2;
+	}
+
+	firstFile = _wfopen(wide_firstPath, L"rb");
+	secondFile = _wfopen(wide_secondPath, L"rb");
+	#else
+	firstFile = fopen(firstPath, "rb");
+	secondFile = fopen(secondPath, "rb");
+	#endif
+
+	if (!firstFile)
+	{
+		if (secondFile)
+			fclose(secondFile);
+
+		lua_pushnil(L);
+		lua_pushstring(L, "failed to open first file");
+		return 2;
+	}
+
+
+	if (!secondFile)
+	{
+		fclose(firstFile);
+
+		lua_pushnil(L);
+		lua_pushstring(L, "failed to open second file");
+		return 2;
+	}
+
+	// check sizes.
+	fseek(firstFile, 0, SEEK_END);
+	firstSize = ftell(firstFile);
+	fseek(firstFile, 0, SEEK_SET);
+
+	fseek(secondFile, 0, SEEK_END);
+	secondSize = ftell(secondFile);
+	fseek(secondFile, 0, SEEK_SET);
+
+	if (firstSize != secondSize)
+	{
+		fclose(firstFile);
+		fclose(secondFile);
+
+		lua_pushboolean(L, 0);
+		return 1;
+	}
+
+	// compare file content
+	while (firstSize > 0)
+	{
+		count = firstSize > 4096 ? 4096 : firstSize;
+
+		read = fread(firstBuffer, 1, count, firstFile);
+		if (read != count)
+		{
+			fclose(firstFile);
+			fclose(secondFile);
+
+			lua_pushnil(L);
+			lua_pushstring(L, "failed to read first file content");
+			return 2;
+		}
+
+		read = fread(secondBuffer, 1, count, secondFile);
+		if (read != count)
+		{
+			fclose(firstFile);
+			fclose(secondFile);
+
+			lua_pushnil(L);
+			lua_pushstring(L, "failed to read second file content");
+			return 2;
+		}
+
+		if (memcmp(firstBuffer, secondBuffer, count) != 0)
+		{
+			fclose(firstFile);
+			fclose(secondFile);
+
+			lua_pushboolean(L, 0);
+			return 1;
+		}
+
+		firstSize -= count;
+	}
+
+	// File content match
+	fclose(firstFile);
+	fclose(secondFile);
+
+	lua_pushboolean(L, 1);
+	return 1;
+}

src/host/premake.c

@@ -57,6 +57,7 @@ static const luaL_Reg path_functions[] = {
 static const luaL_Reg os_functions[] = {
 	{ "chdir",                  os_chdir                },
 	{ "chmod",                  os_chmod                },
+	{ "comparefiles",           os_comparefiles         },
 	{ "copyfile",               os_copyfile             },
 	{ "_is64bit",               os_is64bit              },
 	{ "isdir",                  os_isdir                },

src/host/premake.h

@@ -101,6 +101,7 @@ int path_translate(lua_State* L);
 int path_wildcards(lua_State* L);
 int os_chdir(lua_State* L);
 int os_chmod(lua_State* L);
+int os_comparefiles(lua_State* L);
 int os_copyfile(lua_State* L);
 int os_getcwd(lua_State* L);
 int os_getpass(lua_State* L);