| /* |
| * POSIX 2008 fmemopen(3) implemented in terms of BSD funopen(3) |
| */ |
| |
| /* |
| * Copyright (c) 2013 Taylor R. Campbell |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #define _BSD_SOURCE |
| #define _NETBSD_SOURCE |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "fmemopen.h" |
| |
| struct fmem_cookie { |
| void *fmc_buffer; |
| size_t fmc_index; |
| size_t fmc_limit; |
| }; |
| |
| static int |
| fmem_read(void *cookie, char *buffer, int n) |
| { |
| struct fmem_cookie *const fmc = cookie; |
| |
| if (n < 0) { /* paranoia */ |
| errno = EINVAL; |
| return -1; |
| } |
| |
| if (n > (fmc->fmc_limit - fmc->fmc_index)) |
| n = (fmc->fmc_limit - fmc->fmc_index); |
| |
| (void)memcpy(buffer, (char *)fmc->fmc_buffer + fmc->fmc_index, n); |
| fmc->fmc_index += n; |
| return n; |
| } |
| |
| static int |
| fmem_write(void *cookie, const char *buffer, int n) |
| { |
| struct fmem_cookie *const fmc = cookie; |
| |
| if (n < 0) { /* paranoia */ |
| errno = EINVAL; |
| return -1; |
| } |
| |
| if (n > (fmc->fmc_limit - fmc->fmc_index)) |
| n = (fmc->fmc_limit - fmc->fmc_index); |
| |
| (void)memcpy((char *)fmc->fmc_buffer + fmc->fmc_index, buffer, n); |
| fmc->fmc_index += n; |
| return n; |
| } |
| |
| static fpos_t |
| fmem_seek(void *cookie, fpos_t offset, int cmd) |
| { |
| struct fmem_cookie *const fmc = cookie; |
| |
| switch (cmd) { |
| case SEEK_SET: |
| if ((offset < 0) || (fmc->fmc_limit < offset)) |
| goto einval; |
| fmc->fmc_index = offset; |
| return 0; |
| |
| case SEEK_CUR: |
| if (offset < 0) { |
| /* Assume two's-complement arithmetic. */ |
| if ((offset == ~(fpos_t)0) || (-offset > fmc->fmc_index)) |
| goto einval; |
| } else { |
| if (offset > (fmc->fmc_limit - fmc->fmc_index)) |
| goto einval; |
| } |
| fmc->fmc_index += offset; |
| return 0; |
| |
| case SEEK_END: |
| /* Assume two's-complement arithmetic. */ |
| if ((offset >= 0) || (offset == ~(fpos_t)0) || (fmc->fmc_limit < -offset)) |
| goto einval; |
| fmc->fmc_index = (fmc->fmc_limit + offset); |
| return 0; |
| |
| default: |
| goto einval; |
| } |
| |
| einval: |
| errno = EINVAL; |
| return -1; |
| } |
| |
| static int |
| fmem_close(void *cookie) |
| { |
| struct fmem_cookie *const fmc = cookie; |
| |
| free(fmc); |
| |
| return 0; |
| } |
| |
| FILE * |
| fmemopen(void *buffer, size_t len, const char *mode) |
| { |
| struct fmem_cookie *fmc; |
| FILE *file; |
| |
| fmc = malloc(sizeof(*fmc)); |
| if (fmc == NULL) |
| goto fail0; |
| |
| (void)memset(fmc, 0, sizeof(*fmc)); |
| fmc->fmc_buffer = buffer; |
| fmc->fmc_index = 0; |
| fmc->fmc_limit = len; |
| |
| file = funopen(fmc, &fmem_read, &fmem_write, &fmem_seek, &fmem_close); |
| if (file == NULL) |
| goto fail1; |
| |
| return file; |
| |
| fail1: |
| free(fmc); |
| fail0: |
| return NULL; |
| } |