dedup

commit 8ef5e9d6666a818d610e1e1b1ffefa552f2c76f6
parent a54afccf81b4152c8767ea4eaee2f93e39ac9eba
Author: sin <sin@2f30.org>
Date:   Wed,  8 May 2019 01:14:33 +0100

Implement state file

Diffstat:
M
Makefile
 | 
2
++
A
state.c
 | 
140
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
state.h
 | 
4
++++

3 files changed, 146 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -13,6 +13,7 @@ HDR = \
         misc.h \
         queue.h \
         snap.h \
+        state.h \
         tree.h \
 
 COMMOBJ = \
@@ -27,6 +28,7 @@ COMMOBJ = \
         misc.o \
         pack.o \
         snap.o \
+        state.o \
         unpack.o \
 
 DCHECKOBJ = $(COMMOBJ) dup-check.o
diff --git a/state.c b/state.c
@@ -0,0 +1,140 @@
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <strings.h>
+
+#include "misc.h"
+#include "state.h"
+
+#define VMIN            0
+#define VMAJ            1
+#define VMINMASK        0xff
+#define VMAJSHIFT       8
+#define VMAJMASK        0xff
+
+#define CALGOSHIFT      16
+#define CALGOMASK       0x7
+#define CNONETYPE       0
+#define CSNAPPYTYPE     1
+#define CLZ4TYPE        2
+
+#define EALGOSHIFT      19
+#define EALGOMASK       0x7
+#define ENONETYPE       0
+#define ECHACHATYPE     1
+
+#define SHDRSIZE	8
+
+/* misc helpers */
+extern int pack(unsigned char *, char *, ...);
+extern int unpack(unsigned char *, char *, ...);
+
+struct shdr {
+	uint64_t flags;
+};
+
+/* Read state header */
+static int
+unpackshdr(int fd, struct shdr *shdr)
+{
+	unsigned char buf[SHDRSIZE];
+	int n;
+
+	if (xread(fd, buf, sizeof(buf)) != sizeof(buf))
+		return -1;
+
+	n = unpack(buf, "q", &shdr->flags);
+	assert(n == sizeof(buf));
+	return n;
+}
+
+/* Write state header */
+static int
+packshdr(int fd, struct shdr *shdr)
+{
+	unsigned char buf[SHDRSIZE];
+	int n;
+
+	n = pack(buf, "q", shdr->flags);
+	assert(n == SHDRSIZE);
+	if (xwrite(fd, buf, n) != n)
+		return -1;
+	return n;
+}
+
+int
+savestate(int fd, struct param *par)
+{
+	struct shdr shdr;
+
+	/* Set version */
+	shdr.flags = (VMAJ << VMAJSHIFT) | VMIN;
+
+	/* Set compression type */
+	if (strcasecmp(par->calgo, "none") == 0)
+		shdr.flags |= CNONETYPE << CALGOSHIFT;
+	else if (strcasecmp(par->calgo, "snappy") == 0)
+		shdr.flags |= CSNAPPYTYPE << CALGOSHIFT;
+	else if (strcasecmp(par->calgo, "lz4") == 0)
+		shdr.flags |= CLZ4TYPE << CALGOSHIFT;
+	else
+		return -1;
+
+	/* Set encryption type */
+	if (strcasecmp(par->ealgo, "none") == 0)
+		shdr.flags |= ENONETYPE << EALGOSHIFT;
+	else if (strcasecmp(par->ealgo, "XChaCha20-Poly1305") == 0)
+		shdr.flags |= ECHACHATYPE << EALGOSHIFT;
+	else
+		return -1;
+
+	if (packshdr(fd, &shdr) < 0)
+		return -1;
+	return 0;
+}
+
+int
+loadstate(int fd, struct param *par)
+{
+	struct shdr shdr;
+	int algo;
+
+	if (unpackshdr(fd, &shdr) < 0)
+		return -1;
+
+	/* If the major version is different, the format is incompatible */
+	if (((shdr.flags >> VMAJSHIFT) & VMAJMASK) != VMAJ)
+		return -1;
+
+	/* Populate param compression algo */
+	algo = (shdr.flags >> CALGOSHIFT) & CALGOMASK;
+	switch (algo) {
+	case CNONETYPE:
+		par->calgo = "none";
+		break;
+	case CSNAPPYTYPE:
+		par->calgo = "snappy";
+		break;
+	case CLZ4TYPE:
+		par->calgo = "lz4";
+		break;
+	default:
+		return -1;
+	}
+
+	/* Populate param encryption algo */
+	algo = (shdr.flags >> EALGOSHIFT) & EALGOMASK;
+	switch (algo) {
+	case ENONETYPE:
+		par->ealgo = "none";
+		break;
+	case ECHACHATYPE:
+		par->ealgo = "XChaCha20-Poly1305";
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/state.h b/state.h
@@ -0,0 +1,4 @@
+struct param {
+	char *calgo;
+	char *ealgo;
+};