git.zerfleddert.de Git - proxmark3-svn/blob - client/tinycbor/open_memstream.c

   1 /****************************************************************************
   2 **
   3 ** Copyright (C) 2015 Intel Corporation
   4 **
   5 ** Permission is hereby granted, free of charge, to any person obtaining a copy
   6 ** of this software and associated documentation files (the "Software"), to deal
   7 ** in the Software without restriction, including without limitation the rights
   8 ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 ** copies of the Software, and to permit persons to whom the Software is
  10 ** furnished to do so, subject to the following conditions:
  11 **
  12 ** The above copyright notice and this permission notice shall be included in
  13 ** all copies or substantial portions of the Software.
  14 **
  15 ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 ** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 ** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 ** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 ** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 ** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21 ** THE SOFTWARE.
  22 **
  23 ****************************************************************************/
  24
  25 #define _BSD_SOURCE 1
  26 #define _DEFAULT_SOURCE 1
  27 #define _GNU_SOURCE 1
  28
  29 #include <sys/types.h>
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #if defined(__unix__) || defined(__APPLE__)
  36 #  include <unistd.h>
  37 #endif
  38 #ifdef __APPLE__
  39 typedef int RetType;
  40 typedef int LenType;
  41 #elif __GLIBC__
  42 typedef ssize_t RetType;
  43 typedef size_t LenType;
  44 #else
  45 #  error "Cannot implement open_memstream!"
  46 #endif
  47
  48 #include "compilersupport_p.h"
  49
  50 struct Buffer
  51 {
  52     char **ptr;
  53     size_t *len;
  54     size_t alloc;
  55 };
  56
  57 static RetType write_to_buffer(void *cookie, const char *data, LenType len)
  58 {
  59     struct Buffer *b = (struct Buffer *)cookie;
  60     char *ptr = *b->ptr;
  61     size_t newsize;
  62
  63     errno = EFBIG;
  64     if (unlikely(add_check_overflow(*b->len, len, &newsize)))
  65         return -1;
  66
  67     if (newsize >= b->alloc) { // NB! one extra byte is needed to avoid buffer overflow at close_buffer
  68         // make room
  69         size_t newalloc = newsize + newsize / 2 + 1;    // give 50% more room
  70         ptr = realloc(ptr, newalloc);
  71         if (ptr == NULL)
  72             return -1;
  73         b->alloc = newalloc;
  74         *b->ptr = ptr;
  75     }
  76
  77     memcpy(ptr + *b->len, data, len);
  78     *b->len = newsize;
  79     return len;
  80 }
  81
  82 static int close_buffer(void *cookie)
  83 {
  84     struct Buffer *b = (struct Buffer *)cookie;
  85     if (*b->ptr)
  86         (*b->ptr)[*b->len] = '\0';
  87     free(b);
  88     return 0;
  89 }
  90
  91 FILE *open_memstream(char **bufptr, size_t *lenptr)
  92 {
  93     struct Buffer *b = (struct Buffer *)malloc(sizeof(struct Buffer));
  94     if (b == NULL)
  95         return NULL;
  96     b->alloc = 0;
  97     b->len = lenptr;
  98     b->ptr = bufptr;
  99     *bufptr = NULL;
 100     *lenptr = 0;
 101
 102 #ifdef __APPLE__
 103     return funopen(b, NULL, write_to_buffer, NULL, close_buffer);
 104 #elif __GLIBC__
 105     static const cookie_io_functions_t vtable = {
 106         NULL,
 107         write_to_buffer,
 108         NULL,
 109         close_buffer
 110     };
 111     return fopencookie(b, "w", vtable);
 112 #endif
 113 }
 114