more work on database, initial log reader/writer finished.

database/log.cpp

@@ -1,39 +1,99 @@
-#include <iostream>
-#include <map>
-#include <vector>
+#include <list>
 #include <string>
 #include <cstdlib>
-#include <cstdint>
-
-#include <boost
+#include <cstdio>
+#include <cstring>
+#include <cassert>
+#include <stdint.h>
 
 enum E_OBJ_TYPE { ET_TRANS, ET_HASH, ET_SALE };
 
-struct LogEntry {
+struct __attribute__ ((aligned (64), packed)) LogEntry
+{
 	uint64_t ts;
-	short type;
-	bool revert;
+	E_OBJ_TYPE type;
+	union {
+		struct __attribute__ ((packed)) {
+			char hash[16];
+			int32_t delta;
+		} Transaction;
+
+		struct __attribute__ ((packed)) {
+			char hash[16];
+			bool add;
+		} HashChange;
+
+		struct __attribute__ ((packed)) {
+			char hash[16];
+			uint64_t upc[2];
+			int32_t delta;
+		} StockChange;
+	};
 };
 
-struct Transaction : LogEntry {
-	Transaction() : type(ET_TRANS) {};
-	char hash[16];
-	int32_t delta;
+class Log {
+public:
+	Log(const char * fn)
+		: log_name(fn)
+	{
+		FILE * fh = fopen(fn, "r");
+		if(!fh) {
+			fprintf(stderr, "Log: Could not open log file '%s' for reading!\n", fn);
+			return;
+		}
+
+		LogEntry l;
+		while(1 == fread(&l, sizeof(LogEntry), 1, fh))
+			entries.push_back(l);
+
+		fclose(fh);
+	}
+
+	void writeEntry(LogEntry & ent)
+	{
+		FILE * fh = fopen(log_name.c_str(), "a");
+		assert(fh);
+
+		flockfile(fh);
+
+		fseek(fh, 0, SEEK_END);
+		assert(1 == fwrite(&ent, sizeof(LogEntry), 1, fh));
+		fflush(fh);
+
+		funlockfile(fh);
+		fclose(fh);
+
+		entries.push_back(ent);
+	}
+
+	std::list<LogEntry>::const_iterator begin()
+	{
+		return entries.begin();
+	}
+
+	std::list<LogEntry>::const_iterator end()
+	{
+		return entries.end();
+	}
+private:
+	std::list<LogEntry> entries;
+	std::string log_name;
 };
 
-struct HashChange : LogEntry {
-	HashChange() : type(ET_HASH) {};
-	char hash[16];
-	bool add;
-};
+int main() {
+	LogEntry l;
+	memset(&l, 0, sizeof(LogEntry));
+	l.ts = 0xAAAA;
+	l.type = ET_TRANS;
+	strcpy(l.Transaction.hash, "cocks");
+	l.Transaction.delta = 0xdeadbeef;
 
-struct Sale : LogEntry {
-	Sale() : 
-	char hash[16];
-	uint64_t upc[2];
-};
+	Log cock("cock");
+	cock.writeEntry(l);
 
-struct LogFile {
+	for(std::list<LogEntry>::const_iterator p = cock.begin(); p != cock.end(); ++p)
+		printf("%s\n", p->Transaction.hash);
 
-};
+	return 0;
+}