From 3e351332d4975a0f3a8f641385b9a033439d0e74 Mon Sep 17 00:00:00 2001
From: nishi <nishi@d4a5a174-5a4a-5b4b-b672-37683c10d7d5>
Date: Sat, 18 May 2024 17:21:13 +0000
Subject: [PATCH] can read version now

git-svn-id: file:///raid/svn-main/nishi-dataworks/trunk@37 d4a5a174-5a4a-5b4b-b672-37683c10d7d5
---
 Client/main.c         |  2 +-
 Library/database.c    | 12 +++++++++++-
 Library/dw_database.h |  7 +++++++
 Library/dw_util.h     | 21 +++++++++++++++++++++
 Library/util.c        | 12 ++++++++----
 5 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/Client/main.c b/Client/main.c
index 1f241f0..7487beb 100644
--- a/Client/main.c
+++ b/Client/main.c
@@ -118,7 +118,7 @@ int main(int argc, char** argv) {
 		printf("Bad database file or non-existent.\n");
 		return 1;
 	}
-	printf("Opened the database.\n");
+	printf("Opened the database (Version %d).\n", db->version);
 	printf("\n");
 	printf("Type a command (.help) for the help\n");
 	printf("\n");
diff --git a/Library/database.c b/Library/database.c
index 95078fc..a20b94b 100644
--- a/Library/database.c
+++ b/Library/database.c
@@ -28,10 +28,12 @@
 
 #include "dw_database.h"
 
+#include "dw_util.h"
+
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
+#include <string.h>
 
 const char sig[3] = {0x7f, 'D', 'W'};
 
@@ -69,7 +71,15 @@ struct dataworks_db* dataworks_database_open(const char* fname) {
 		fclose(fp);
 		return NULL;
 	}
+	__dw_lockfile(fp);
+	char ptrver[2];
+	fread(ptrver, 1, 2, fp);
+	uint16_t be_ver = *(uint16_t*)(char*)ptrver;
+	uint16_t ver;
+	__dw_native_endian(be_ver, uint16_t, ver = __converted);
+	__dw_unlockfile(fp);
 	struct dataworks_db* db = malloc(sizeof(*db));
 	db->fp = fp;
+	db->version = ver;
 	return db;
 }
diff --git a/Library/dw_database.h b/Library/dw_database.h
index ec8ca1a..a96ed9c 100644
--- a/Library/dw_database.h
+++ b/Library/dw_database.h
@@ -40,6 +40,7 @@
 extern "C" {
 #endif
 
+#include <stdint.h>
 #include <stdio.h>
 
 /**
@@ -54,6 +55,12 @@ struct dataworks_db {
 	 *
 	 */
 	FILE* fp;
+	/**
+	 * @~english
+	 * @brief Version of the database version.
+	 *
+	 */
+	uint16_t version;
 };
 
 /**
diff --git a/Library/dw_util.h b/Library/dw_util.h
index 1c5c178..549b0e5 100644
--- a/Library/dw_util.h
+++ b/Library/dw_util.h
@@ -52,6 +52,7 @@ bool __dw_unlockfile(FILE* fp);
 #define __dw_xstr(x) #x
 #define __dw_str(x) __dw_xstr(x)
 
+/* Converts NE to BE */
 #define __dw_big_endian(arg, type, exec) \
 	{ \
 		type __original = arg; \
@@ -71,6 +72,26 @@ bool __dw_unlockfile(FILE* fp);
 		exec; \
 	}
 
+/* Converts BE to NE */
+#define __dw_native_endian(arg, type, exec) \
+	{ \
+		type __original = arg; \
+		signed char* __ptr = (signed char*)&__original; \
+		type __converted; \
+		signed char* __converted_ptr = (signed char*)&__converted; \
+		int __i; \
+		int __endian_check = 1; \
+		char __endian = (1 == *(volatile char*)&__endian_check) ? 'L' : 'B'; \
+		for(__i = 0; __i < sizeof(type); __i++) { \
+			if(__endian == 'L') { \
+				__converted_ptr[sizeof(type) - __i - 1] = __ptr[__i]; \
+			} else { \
+				__converted_ptr[__i] = __ptr[__i]; \
+			} \
+		} \
+		exec; \
+	}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Library/util.c b/Library/util.c
index 9273a17..2ac0124 100644
--- a/Library/util.c
+++ b/Library/util.c
@@ -46,24 +46,28 @@ bool __dw_strcaseequ(const char* a, const char* b) {
 	return true;
 }
 
-bool __dw_lockfile(FILE* fp){
+bool __dw_lockfile(FILE* fp) {
+	off_t off = ftell(fp);
+	fseek(fp, 0, SEEK_SET);
 #ifdef __MINGW32__
 	OVERLAPPED overlap = {0};
 	LockFileEx(fp, LOCKFILE_EXCLUSIVE_LOCK, 0, MAXDWORD, MAXDWORD, &overlap);
 #else
-	fseek(fp, SEEK_SET, 0);
 	lockf(fileno(fp), F_LOCK, 0);
 #endif
+	fseek(fp, off, SEEK_SET);
 	return false;
 }
 
-bool __dw_unlockfile(FILE* fp){
+bool __dw_unlockfile(FILE* fp) {
+	off_t off = ftell(fp);
+	fseek(fp, 0, SEEK_SET);
 #ifdef __MINGW32__
 	OVERLAPPED overlap = {0};
 	UnlockFileEx(fp, 0, MAXDWORD, MAXDWORD, &overlap);
 #else
-	fseek(fp, SEEK_SET, 0);
 	lockf(fileno(fp), F_ULOCK, 0);
 #endif
+	fseek(fp, off, SEEK_SET);
 	return false;
 }
-- 
2.43.0