add string.sha1 function

src/host/premake.c

@@ -80,6 +80,7 @@ static const luaL_Reg os_functions[] = {
 static const luaL_Reg string_functions[] = {
 	{ "endswith",  string_endswith },
 	{ "hash", string_hash },
+	{ "sha1", string_sha1 },
 	{ "startswith", string_startswith },
 	{ NULL, NULL }
 };

src/host/premake.h

@@ -118,6 +118,7 @@ int os_stat(lua_State* L);
 int os_uuid(lua_State* L);
 int string_endswith(lua_State* L);
 int string_hash(lua_State* L);
+int string_sha1(lua_State* L);
 int string_startswith(lua_State* L);
 
 /* Engine interface */

src/host/string_sha1.c

@@ -0,0 +1,185 @@
+#include <stdint.h>
+#include <string.h>
+#include "premake.h"
+
+#define HASH_LENGTH 20
+#define BLOCK_LENGTH 64
+
+typedef struct sha1nfo {
+	uint32_t buffer[BLOCK_LENGTH / 4];
+	uint32_t state[HASH_LENGTH / 4];
+	uint32_t byteCount;
+	uint8_t bufferOffset;
+	uint8_t keyBuffer[BLOCK_LENGTH];
+	uint8_t innerHash[HASH_LENGTH];
+} sha1nfo;
+
+/* public API - prototypes - TODO: doxygen*/
+void sha1_init(sha1nfo *s);
+void sha1_writebyte(sha1nfo *s, uint8_t data);
+void sha1_write(sha1nfo *s, const char *data, size_t len);
+uint8_t* sha1_result(sha1nfo *s);
+
+/* code */
+#define SHA1_K0  0x5a827999
+#define SHA1_K20 0x6ed9eba1
+#define SHA1_K40 0x8f1bbcdc
+#define SHA1_K60 0xca62c1d6
+
+void sha1_init(sha1nfo *s)
+{
+	s->state[0] = 0x67452301;
+	s->state[1] = 0xefcdab89;
+	s->state[2] = 0x98badcfe;
+	s->state[3] = 0x10325476;
+	s->state[4] = 0xc3d2e1f0;
+	s->byteCount = 0;
+	s->bufferOffset = 0;
+}
+
+uint32_t sha1_rol32(uint32_t number, uint8_t bits)
+{
+	return ((number << bits) | (number >> (32 - bits)));
+}
+
+void sha1_hashBlock(sha1nfo *s)
+{
+	uint8_t i;
+	uint32_t a, b, c, d, e, t;
+
+	a = s->state[0];
+	b = s->state[1];
+	c = s->state[2];
+	d = s->state[3];
+	e = s->state[4];
+	for (i = 0; i < 80; i++)
+	{
+		if (i >= 16)
+		{
+			t = s->buffer[(i + 13) & 15] ^ s->buffer[(i + 8) & 15] ^ s->buffer[(i + 2) & 15] ^ s->buffer[i & 15];
+			s->buffer[i & 15] = sha1_rol32(t, 1);
+		}
+		if (i < 20)
+		{
+			t = (d ^ (b & (c ^ d))) + SHA1_K0;
+		}
+		else if (i < 40)
+		{
+			t = (b ^ c ^ d) + SHA1_K20;
+		}
+		else if (i < 60)
+		{
+			t = ((b & c) | (d & (b | c))) + SHA1_K40;
+		}
+		else
+		{
+			t = (b ^ c ^ d) + SHA1_K60;
+		}
+		t += sha1_rol32(a, 5) + e + s->buffer[i & 15];
+		e = d;
+		d = c;
+		c = sha1_rol32(b, 30);
+		b = a;
+		a = t;
+	}
+	s->state[0] += a;
+	s->state[1] += b;
+	s->state[2] += c;
+	s->state[3] += d;
+	s->state[4] += e;
+}
+
+void sha1_addUncounted(sha1nfo *s, uint8_t data)
+{
+	uint8_t * const b = (uint8_t*)s->buffer;
+	b[s->bufferOffset ^ 3] = data;
+	s->bufferOffset++;
+	if (s->bufferOffset == BLOCK_LENGTH)
+	{
+		sha1_hashBlock(s);
+		s->bufferOffset = 0;
+	}
+}
+
+void sha1_writebyte(sha1nfo *s, uint8_t data)
+{
+	++s->byteCount;
+	sha1_addUncounted(s, data);
+}
+
+void sha1_write(sha1nfo *s, const char *data, size_t len)
+{
+	for (; len--;) sha1_writebyte(s, (uint8_t)*data++);
+}
+
+void sha1_pad(sha1nfo *s) 
+{
+	// Implement SHA-1 padding (fips180-2 §5.1.1)
+
+	// Pad with 0x80 followed by 0x00 until the end of the block
+	sha1_addUncounted(s, 0x80);
+	while (s->bufferOffset != 56) sha1_addUncounted(s, 0x00);
+
+	// Append length in the last 8 bytes
+	sha1_addUncounted(s, 0); // We're only using 32 bit lengths
+	sha1_addUncounted(s, 0); // But SHA-1 supports 64 bit lengths
+	sha1_addUncounted(s, 0); // So zero pad the top bits
+	sha1_addUncounted(s, s->byteCount >> 29); // Shifting to multiply by 8
+	sha1_addUncounted(s, (uint8_t)(s->byteCount >> 21)); // as SHA-1 supports bitstreams as well as
+	sha1_addUncounted(s, (uint8_t)(s->byteCount >> 13)); // byte.
+	sha1_addUncounted(s, (uint8_t)(s->byteCount >> 5));
+	sha1_addUncounted(s, (uint8_t)(s->byteCount << 3));
+}
+
+uint8_t* sha1_result(sha1nfo *s) 
+{
+	int i;
+
+	// Pad to complete the last block
+	sha1_pad(s);
+
+	// Swap byte order back
+	for (i = 0; i < 5; i++) 
+	{
+		s->state[i] =
+			(((s->state[i]) << 24) & 0xff000000)
+			| (((s->state[i]) << 8) & 0x00ff0000)
+			| (((s->state[i]) >> 8) & 0x0000ff00)
+			| (((s->state[i]) >> 24) & 0x000000ff);
+	}
+
+	// Return pointer to hash (20 characters)
+	return (uint8_t*)s->state;
+}
+
+
+
+int string_sha1(lua_State* L)
+{
+	static const char* g_int2hex = "0123456789ABCDEF";
+	uint8_t* result;
+	size_t l;
+	sha1nfo s;
+	int i;
+	char output[41];
+
+	const char *str = luaL_checklstring(L, 1, &l);
+	if (str != NULL)
+	{
+		sha1_init(&s);
+		sha1_write(&s, str, l);
+		result = sha1_result(&s);
+
+		for (i = 0; i < 20; ++i)
+		{
+			output[i * 2 + 0] = g_int2hex[result[i] & 0x0f];
+			output[i * 2 + 1] = g_int2hex[result[i] >> 4];
+		}
+		output[40] = 0;
+
+		lua_pushlstring(L, output, 40);
+		return 1;
+	}
+
+	return 0;
+}