core: C++-ify SHA1 interface

All callers of the SHA1 code are C++. Might just as well use
a C++ like interface.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

Subsurface-mobile.pro

@@ -91,7 +91,7 @@ SOURCES += subsurface-mobile-main.cpp \
 	core/gas.c \
 	core/membuffer.cpp \
 	core/selection.cpp \
-	core/sha1.c \
+	core/sha1.cpp \
 	core/string-format.cpp \
 	core/strtod.cpp \
 	core/tag.cpp \

core/CMakeLists.txt

@@ -162,7 +162,7 @@ set(SUBSURFACE_CORE_LIB_SRCS
 	save-xml.cpp
 	selection.cpp
 	selection.h
-	sha1.c
+	sha1.cpp
 	sha1.h
 	ssrf.h
 	statistics.c

core/divesite.cpp

@@ -138,18 +138,14 @@ extern "C" int add_dive_site_to_table(struct dive_site *ds, struct dive_site_tab
 	/* If the site doesn't yet have an UUID, create a new one.
 	 * Make this deterministic for testing. */
 	if (!ds->uuid) {
-		SHA_CTX ctx;
-		uint32_t csum[5];
-
-		SHA1_Init(&ctx);
+		SHA1 sha;
 		if (ds->name)
-			SHA1_Update(&ctx, ds->name, strlen(ds->name));
+			sha.update(ds->name, strlen(ds->name));
 		if (ds->description)
-			SHA1_Update(&ctx, ds->description, strlen(ds->description));
+			sha.update(ds->description, strlen(ds->description));
 		if (ds->notes)
-			SHA1_Update(&ctx, ds->notes, strlen(ds->notes));
-		SHA1_Final((unsigned char *)csum, &ctx);
-		ds->uuid = csum[0];
+			sha.update(ds->notes, strlen(ds->notes));
+		ds->uuid = sha.hash_uint32();
 	}
 
 	/* Take care to never have the same uuid twice. This could happen on

core/git-access.cpp

@@ -135,9 +135,6 @@ std::string normalize_cloud_name(const std::string &remote_in)
 
 std::string get_local_dir(const std::string &url, const std::string &branch)
 {
-	SHA_CTX ctx;
-	unsigned char hash[20];
-
 	// this optimization could in theory lead to odd things happening if the
 	// cloud backend servers ever get out of sync - but when a user switches
 	// between those servers (either because one is down, or because the algorithm
@@ -148,11 +145,11 @@ std::string get_local_dir(const std::string &url, const std::string &branch)
 
 	// That zero-byte update is so that we don't get hash
 	// collisions for "repo1 branch" vs "repo 1branch".
-	SHA1_Init(&ctx);
-	SHA1_Update(&ctx, remote.c_str(), remote.size());
-	SHA1_Update(&ctx, "", 1);
-	SHA1_Update(&ctx, branch.c_str(), branch.size());
-	SHA1_Final(hash, &ctx);
+	SHA1 sha;
+	sha.update(remote);
+	sha.update("", 1);
+	sha.update(branch);
+	auto hash = sha.hash();
 	return format_string_std("%s/cloudstorage/%02x%02x%02x%02x%02x%02x%02x%02x",
 			system_default_directory(),
 			hash[0], hash[1], hash[2], hash[3],

core/sha1.cpp

@@ -8,7 +8,6 @@
 
 /* this is only to get definitions for memcpy(), ntohl() and htonl() */
 #include <string.h>
-#include <stdint.h>
 #ifdef WIN32
 #include <winsock2.h>
 #else
@@ -132,16 +131,16 @@
 #define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B &C) + (D &(B ^ C))), 0x8f1bbcdc, A, B, C, D, E)
 #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B ^ C ^ D), 0xca62c1d6, A, B, C, D, E)
 
-static void blk_SHA1_Block(blk_SHA_CTX *ctx, const void *block)
+static void blk_SHA1_Block(unsigned int H[], const void *block)
 {
 	unsigned int A, B, C, D, E;
 	unsigned int array[16];
 
-	A = ctx->H[0];
-	B = ctx->H[1];
-	C = ctx->H[2];
-	D = ctx->H[3];
-	E = ctx->H[4];
+	A = H[0];
+	B = H[1];
+	C = H[2];
+	D = H[3];
+	E = H[4];
 
 	/* Round 1 - iterations 0-16 take their input from 'block' */
 	T_0_15(0, A, B, C, D, E);
@@ -233,80 +232,84 @@ static void blk_SHA1_Block(blk_SHA_CTX *ctx, const void *block)
 	T_60_79(78, C, D, E, A, B);
 	T_60_79(79, B, C, D, E, A);
 
-	ctx->H[0] += A;
-	ctx->H[1] += B;
-	ctx->H[2] += C;
-	ctx->H[3] += D;
-	ctx->H[4] += E;
+	H[0] += A;
+	H[1] += B;
+	H[2] += C;
+	H[3] += D;
+	H[4] += E;
 }
 
-void blk_SHA1_Init(blk_SHA_CTX *ctx)
-{
-	ctx->size = 0;
-
+SHA1::SHA1() :
+	size(0),
 	/* Initialize H with the magic constants (see FIPS180 for constants) */
-	ctx->H[0] = 0x67452301;
-	ctx->H[1] = 0xefcdab89;
-	ctx->H[2] = 0x98badcfe;
-	ctx->H[3] = 0x10325476;
-	ctx->H[4] = 0xc3d2e1f0;
+	H { 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0 }
+{
 }
 
-void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
+void SHA1::update(const void *data, unsigned long len)
 {
-	unsigned int lenW = ctx->size & 63;
+	unsigned int lenW = size & 63;
 
-	ctx->size += len;
+	size += len;
 
 	/* Read the data into W and process blocks as they get full */
 	if (lenW) {
 		unsigned int left = 64 - lenW;
 		if (len < left)
 			left = len;
-		memcpy(lenW + (char *)ctx->W, data, left);
+		memcpy(lenW + (char *)W, data, left);
 		lenW = (lenW + left) & 63;
 		len -= left;
 		data = ((const char *)data + left);
 		if (lenW)
 			return;
-		blk_SHA1_Block(ctx, ctx->W);
+		blk_SHA1_Block(H, W);
 	}
 	while (len >= 64) {
-		blk_SHA1_Block(ctx, data);
+		blk_SHA1_Block(H, data);
 		data = ((const char *)data + 64);
 		len -= 64;
 	}
 	if (len)
-		memcpy(ctx->W, data, len);
+		memcpy(W, data, len);
 }
 
-void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
+void SHA1::update(const std::string &s)
 {
+	update(s.data(), s.size());
+}
+
+std::array<unsigned char, 20> SHA1::hash()
+{
+	std::array<unsigned char, 20> hashout;
 	static const unsigned char pad[64] = { 0x80 };
 	unsigned int padlen[2];
 	int i;
 
 	/* Pad with a binary 1 (ie 0x80), then zeroes, then length */
-	padlen[0] = htonl((uint32_t)(ctx->size >> 29));
-	padlen[1] = htonl((uint32_t)(ctx->size << 3));
+	padlen[0] = htonl((uint32_t)(size >> 29));
+	padlen[1] = htonl((uint32_t)(size << 3));
 
-	i = ctx->size & 63;
-	blk_SHA1_Update(ctx, pad, 1 + (63 & (55 - i)));
-	blk_SHA1_Update(ctx, padlen, 8);
+	i = size & 63;
+	update(pad, 1 + (63 & (55 - i)));
+	update(padlen, 8);
 
 	/* Output hash */
 	for (i = 0; i < 5; i++)
-		put_be32(hashout + i * 4, ctx->H[i]);
+		put_be32(&hashout[i * 4], H[i]);
+	return hashout;
+}
+
+uint32_t SHA1::hash_uint32()
+{
+	auto hashout = hash();
+	return (hashout[0] << 0) | (hashout[1] << 8) |
+	       (hashout[2] << 16) | (hashout[3] << 24);
 }
 
 uint32_t SHA1_uint32(const void *dataIn, unsigned long len)
 {
-	uint32_t hashout[5];
-	SHA_CTX ctx;
-
-	SHA1_Init(&ctx);
-	SHA1_Update(&ctx, dataIn, len);
-	SHA1_Final((unsigned char *)hashout, &ctx);
-
-	return hashout[0];
+	SHA1 sha;
+	sha.update(dataIn, len);
+	return sha.hash_uint32();
 }

core/sha1.h

@@ -9,31 +9,28 @@
 #define SHA1_H
 
 #ifdef __cplusplus
-extern "C" {
-#endif
 
-typedef struct
+#include <array>
+#include <string>
+
+struct SHA1
 {
+	SHA1();
+	void update(const void *dataIn, unsigned long len);
+	void update(const std::string &s);
+	// Note: the hash() functions change state. Call only once.
+	std::array<unsigned char, 20> hash();
+	uint32_t hash_uint32(); // Return first 4 bytes of hash interpreted
+				// as little-endian unsigned integer.
+private:
 	unsigned long long size;
 	unsigned int H[5];
 	unsigned int W[16];
-} blk_SHA_CTX;
-
-void blk_SHA1_Init(blk_SHA_CTX *ctx);
-void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, unsigned long len);
-void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
-
-/* Make us use the standard names */
-#define SHA_CTX blk_SHA_CTX
-#define SHA1_Init blk_SHA1_Init
-#define SHA1_Update blk_SHA1_Update
-#define SHA1_Final blk_SHA1_Final
+};
 
 /* Helper function that calculates an SHA1 has and returns the first 4 bytes as uint32_t */
 uint32_t SHA1_uint32(const void *dataIn, unsigned long len);
 
-#ifdef __cplusplus
-}
 #endif
 
 #endif // SHA1_H