2 * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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34 #include "krb5_locl.h"
35 #include "store-int.h"
39 typedef struct emem_storage{
47 emem_fetch(krb5_storage *sp, void *data, size_t size)
49 emem_storage *s = (emem_storage*)sp->data;
50 if(s->base + s->len - s->ptr < size)
51 size = s->base + s->len - s->ptr;
52 memmove(data, s->ptr, size);
53 sp->seek(sp, size, SEEK_CUR);
58 emem_store(krb5_storage *sp, const void *data, size_t size)
60 emem_storage *s = (emem_storage*)sp->data;
61 if(size > s->base + s->size - s->ptr){
64 off = s->ptr - s->base;
68 base = realloc(s->base, sz);
73 s->ptr = (unsigned char*)base + off;
75 memmove(s->ptr, data, size);
76 sp->seek(sp, size, SEEK_CUR);
81 emem_seek(krb5_storage *sp, off_t offset, int whence)
83 emem_storage *s = (emem_storage*)sp->data;
90 s->ptr = s->base + offset;
95 sp->seek(sp,s->ptr - s->base + offset, SEEK_SET);
98 sp->seek(sp, s->len + offset, SEEK_SET);
104 return s->ptr - s->base;
108 emem_trunc(krb5_storage *sp, off_t offset)
110 emem_storage *s = (emem_storage*)sp->data;
112 * If offset is larget then current size, or current size is
113 * shrunk more then half of the current size, adjust buffer.
115 if (offset > s->size || (s->size / 2) > offset) {
118 off = s->ptr - s->base;
119 base = realloc(s->base, offset);
122 if (offset > s->size)
123 memset((char *)base + s->size, 0, offset - s->size);
126 s->ptr = (unsigned char *)base + off;
129 if ((s->ptr - s->base) > offset)
130 s->ptr = s->base + offset;
136 emem_free(krb5_storage *sp)
138 emem_storage *s = sp->data;
139 memset(s->base, 0, s->len);
144 * Create a elastic (allocating) memory storage backend. Memory is
145 * allocated on demand. Free returned krb5_storage with
146 * krb5_storage_free().
148 * @return A krb5_storage on success, or NULL on out of memory error.
150 * @ingroup krb5_storage
152 * @sa krb5_storage_from_mem()
153 * @sa krb5_storage_from_readonly_mem()
154 * @sa krb5_storage_from_fd()
155 * @sa krb5_storage_from_data()
158 krb5_storage * KRB5_LIB_FUNCTION
159 krb5_storage_emem(void)
164 sp = malloc(sizeof(krb5_storage));
168 s = malloc(sizeof(*s));
175 sp->eof_code = HEIM_ERR_EOF;
177 s->base = malloc(s->size);
178 if (s->base == NULL) {
185 sp->fetch = emem_fetch;
186 sp->store = emem_store;
187 sp->seek = emem_seek;
188 sp->trunc = emem_trunc;
189 sp->free = emem_free;