src/prc1/push.c


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#include "prv.h"
#include "dbg.h"
#include <stdlib.h>

int push(const struct pos *pos, struct prv *p)
{
    size_t n = p->n + 1;
    struct pos *npos = realloc(p->pos, n * sizeof *npos), *pp;

    if (!npos)
    {
        perror("realloc(3)");
        return -1;
    }
    else if (p->n)
    {
        struct pos *prev = &npos[p->n - 1];

        prev->seq = prev->stseq;
        prev->step = prev->seq->steps;
        p->i++;
    }

    ddbg("push rule %s [%zu]", pos->name, p->n);

    if (pos->end)
        ddbg(", end=%p", pos->end);

    ddbg("\n");
    pp = &npos[p->n++];
    *pp = *pos;
    pp->stseq = pp->seq;
    pp->step = pp->seq->steps;
    p->pos = npos;
    return 0;
}