plan9-sha1.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include <venti.h>
#include <libsec.h>

static void encode(uchar*, u32int*, ulong);
extern void vtSha1Block(u32int *s, uchar *p, ulong len);

struct VtSha1
{
	DigestState *s;
};

VtSha1 *
vtSha1Alloc(void)
{
	VtSha1 *s;

	s = vtMemAlloc(sizeof(VtSha1));
	vtSha1Init(s);
	return s;
}

void
vtSha1Free(VtSha1 *s)
{
	if(s == nil)
		return;
	if(s->s != nil)
		free(s->s);
	vtMemFree(s);
}

void
vtSha1Init(VtSha1 *s)
{
	s->s = nil;
}

void
vtSha1Update(VtSha1 *s, uchar *p, int len)
{
	s->s = sha1(p, len, nil, s->s);
}

void
vtSha1Final(VtSha1 *s, uchar *digest)
{
	sha1(nil, 0, digest, s->s);
	s->s = nil;
}

void
vtSha1(uchar sha1[VtScoreSize], uchar *p, int n)
{
	VtSha1 s;

	vtSha1Init(&s);
	vtSha1Update(&s, p, n);
	vtSha1Final(&s, sha1);
}

int
vtSha1Check(uchar score[VtScoreSize], uchar *p, int n)
{
	VtSha1 s;
	uchar score2[VtScoreSize];

	vtSha1Init(&s);
	vtSha1Update(&s, p, n);
	vtSha1Final(&s, score2);

	if(memcmp(score, score2, VtScoreSize) != 0) {
		vtSetError("vtSha1Check failed");
		return 0;
	}
	return 1;
}