codexlib/sum/sum.c

#pragma prototyped

/*
 * checksum filter
 */

#include <codex.h>
#include <sum.h>

typedef struct State_s
{
    Codex_t     codex;

    Sum_t*      sum;
} State_t;

static int
sum_options(Codexmeth_t* meth, Sfio_t* sp)
{
    return sumusage(sp) >= 0 ? 0 : -1;
}

static int
sum_open(Codex_t* p, char* const args[], Codexnum_t flags)
{
    register State_t*   state;
    register Sum_t*     sum;
    register const char*    s;

    s = args[0];
    if (args[2])
        while (*s && *s++ != '-');
    if (!(sum = sumopen(s)))
    {
        if (p->disc->errorf)
            (*p->disc->errorf)(NiL, p->disc, 2, "%s: unknown method", args[0]);
        return -1;
    }
    if (!(state = newof(0, State_t, 1, 0)))
    {
        if (p->disc->errorf)
            (*p->disc->errorf)(NiL, p->disc, 2, "out of space");
        return -1;
    }
    state->sum = sum;
    p->data = state;
    return 0;
}

static int
sum_init(Codex_t* p)
{
    return suminit(((State_t*)p->data)->sum);
}

static int
sum_close(Codex_t* p)
{
    return sumclose(((State_t*)p->data)->sum);
}

static ssize_t
sum_read(Sfio_t* sp, void* buf, size_t n, Sfdisc_t* disc)
{
    ssize_t     r;

    if ((r = sfrd(sp, buf, n, disc)) > 0)
        sumblock(((State_t*)CODEX(disc)->data)->sum, buf, r);
    return r;
}

static ssize_t
sum_write(Sfio_t* sp, const void* buf, size_t n, Sfdisc_t* disc)
{
    ssize_t     r;

    if ((r = sfwr(sp, buf, n, disc)) > 0)
        sumblock(((State_t*)CODEX(disc)->data)->sum, buf, r);
    return r;
}

static int
sum_data(Codex_t* p, Codexdata_t* data)
{
    sumdone(((State_t*)p->data)->sum);
    return sumdata(((State_t*)p->data)->sum, (Sumdata_t*)data);
}

Codexmeth_t codex_sum =
{
    "sum",
    "checksum filter. The checksum value returned by \bcodexdata\b(3) is"
    " written to the standard error.",
    "[+(version)?codex-sum (AT&T Research) 2003-12-16]"
    "[+(author)?Glenn Fowler <gsf@research.att.com>]",
    CODEX_DECODE|CODEX_ENCODE|CODEX_SUM,
    sum_options,
    0,
    sum_open,
    0,
    sum_init,
    0,
    sum_read,
    sum_write,
    sum_init,
    0,
    sum_data,
    0,
    0,
    CODEXNEXT(sum)
};

CODEXLIB(sum)