typedef struct {
    unsigned int count[2];
    unsigned int state[5];
    unsigned char buffer[264];
} SHA1_CTX;


void SHA1Init(SHA1_CTX* context);
void SHA1Update(SHA1_CTX* context, const unsigned char* data, unsigned int len);
void SHA1Transform(unsigned int state[5], const unsigned char buffer[64]);
void SHA1Final(SHA1_CTX* context, unsigned char digest[20]);

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
#define blk0(i) block->l[i]
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);