rewrite iov_* functions

[qemu.git] / iov.c

/*
 * Helpers for getting linearized buffers from iov / filling buffers into iovs
 *
 * Copyright IBM, Corp. 2007, 2008
 * Copyright (C) 2010 Red Hat, Inc.
 *
 * Author(s):
 *  Anthony Liguori <aliguori@us.ibm.com>
 *  Amit Shah <amit.shah@redhat.com>
 *  Michael Tokarev <mjt@tls.msk.ru>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 * Contributions after 2012-01-13 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 */

#include "iov.h"

size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
                    size_t offset, const void *buf, size_t bytes)
{
    size_t done;
    unsigned int i;
    for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
        if (offset < iov[i].iov_len) {
            size_t len = MIN(iov[i].iov_len - offset, bytes - done);
            memcpy(iov[i].iov_base + offset, buf + done, len);
            done += len;
            offset = 0;
        } else {
            offset -= iov[i].iov_len;
        }
    }
    assert(offset == 0);
    return done;
}

size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
                  size_t offset, void *buf, size_t bytes)
{
    size_t done;
    unsigned int i;
    for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
        if (offset < iov[i].iov_len) {
            size_t len = MIN(iov[i].iov_len - offset, bytes - done);
            memcpy(buf + done, iov[i].iov_base + offset, len);
            done += len;
            offset = 0;
        } else {
            offset -= iov[i].iov_len;
        }
    }
    assert(offset == 0);
    return done;
}

size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
                  size_t offset, int fillc, size_t bytes)
{
    size_t done;
    unsigned int i;
    for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
        if (offset < iov[i].iov_len) {
            size_t len = MIN(iov[i].iov_len - offset, bytes - done);
            memset(iov[i].iov_base + offset, fillc, len);
            done += len;
            offset = 0;
        } else {
            offset -= iov[i].iov_len;
        }
    }
    assert(offset == 0);
    return done;
}

size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
{
    size_t len;
    unsigned int i;

    len = 0;
    for (i = 0; i < iov_cnt; i++) {
        len += iov[i].iov_len;
    }
    return len;
}

void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
                 FILE *fp, const char *prefix, size_t limit)
{
    unsigned int i, v, b;
    uint8_t *c;

    c = iov[0].iov_base;
    for (i = 0, v = 0, b = 0; b < limit; i++, b++) {
        if (i == iov[v].iov_len) {
            i = 0; v++;
            if (v == iov_cnt) {
                break;
            }
            c = iov[v].iov_base;
        }
        if ((b % 16) == 0) {
            fprintf(fp, "%s: %04x:", prefix, b);
        }
        if ((b % 4) == 0) {
            fprintf(fp, " ");
        }
        fprintf(fp, " %02x", c[i]);
        if ((b % 16) == 15) {
            fprintf(fp, "\n");
        }
    }
    if ((b % 16) != 0) {
        fprintf(fp, "\n");
    }
}