Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include <flate.h>
#include "zlib.h"

typedef struct Block    Block;

struct Block
{
        uchar   *pos;
        uchar   *limit;
};

static int
blgetc(void *vb)
{
        Block *b;

        b = vb;
        if(b->pos >= b->limit)
                return -1;
        return *b->pos++;
}

static int
blwrite(void *vb, void *buf, int n)
{
        Block *b;

        b = vb;

        if(n > b->limit - b->pos)
                n = b->limit - b->pos;
        memmove(b->pos, buf, n);
        b->pos += n;
        return n;
}

int
inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize)
{
        Block bd, bs;
        int ok;

        if(ssize < 6)
                return FlateInputFail;

        if(((src[0] << 8) | src[1]) % 31)
                return FlateCorrupted;
        if((src[0] & ZlibMeth) != ZlibDeflate
        || (src[0] & ZlibCInfo) > ZlibWin32k)
                return FlateCorrupted;

        bs.pos = src + 2;
        bs.limit = src + ssize - 6;

        bd.pos = dst;
        bd.limit = dst + dsize;

        ok = inflate(&bd, blwrite, &bs, blgetc);
        if(ok != FlateOk)
                return ok;

        if(adler32(1, dst, bs.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3]))
                return FlateCorrupted;

        return bd.pos - dst;
}