rework langinfo code for ABI compat and for use by time code

[musl] / src / stdio / __string_read.c

#include "stdio_impl.h"
#include <string.h>

size_t __string_read(FILE *f, unsigned char *buf, size_t len)
{
        char *src = f->cookie;
        size_t k = len+256;
        char *end = memchr(src, 0, k);
        if (end) k = end-src;
        if (k < len) len = k;
        memcpy(buf, src, len);
        f->rpos = (void *)(src+len);
        f->rend = (void *)(src+k);
        f->cookie = src+k;
        return len;
}