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Diffstat (limited to 'lib/ofpbuf.c')
| -rw-r--r-- | lib/ofpbuf.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c new file mode 100644 index 000000000..ed326fd5c --- /dev/null +++ b/lib/ofpbuf.c @@ -0,0 +1,288 @@ +/* + * Copyright (c) 2008, 2009 Nicira Networks. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <config.h> +#include "ofpbuf.h" +#include <assert.h> +#include <stdlib.h> +#include <string.h> +#include "util.h" + +/* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of + * memory starting at 'base'. + * + * 'base' should ordinarily be the first byte of a region obtained from + * malloc(), but in circumstances where it can be guaranteed that 'b' will + * never need to be expanded or freed, it can be a pointer into arbitrary + * memory. */ +void +ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated) +{ + b->base = b->data = base; + b->allocated = allocated; + b->size = 0; + b->l2 = b->l3 = b->l4 = b->l7 = NULL; + b->next = NULL; + b->private = NULL; +} + +/* Initializes 'b' as an empty ofpbuf with an initial capacity of 'size' + * bytes. */ +void +ofpbuf_init(struct ofpbuf *b, size_t size) +{ + ofpbuf_use(b, size ? xmalloc(size) : NULL, size); +} + +/* Frees memory that 'b' points to. */ +void +ofpbuf_uninit(struct ofpbuf *b) +{ + if (b) { + free(b->base); + } +} + +/* Frees memory that 'b' points to and allocates a new ofpbuf */ +void +ofpbuf_reinit(struct ofpbuf *b, size_t size) +{ + ofpbuf_uninit(b); + ofpbuf_init(b, size); +} + +/* Creates and returns a new ofpbuf with an initial capacity of 'size' + * bytes. */ +struct ofpbuf * +ofpbuf_new(size_t size) +{ + struct ofpbuf *b = xmalloc(sizeof *b); + ofpbuf_init(b, size); + return b; +} + +struct ofpbuf * +ofpbuf_clone(const struct ofpbuf *buffer) +{ + return ofpbuf_clone_data(buffer->data, buffer->size); +} + +struct ofpbuf * +ofpbuf_clone_data(const void *data, size_t size) +{ + struct ofpbuf *b = ofpbuf_new(size); + ofpbuf_put(b, data, size); + return b; +} + +/* Frees memory that 'b' points to, as well as 'b' itself. */ +void +ofpbuf_delete(struct ofpbuf *b) +{ + if (b) { + ofpbuf_uninit(b); + free(b); + } +} + +/* Returns the number of bytes of headroom in 'b', that is, the number of bytes + * of unused space in ofpbuf 'b' before the data that is in use. (Most + * commonly, the data in a ofpbuf is at its beginning, and thus the ofpbuf's + * headroom is 0.) */ +size_t +ofpbuf_headroom(struct ofpbuf *b) +{ + return (char*)b->data - (char*)b->base; +} + +/* Returns the number of bytes that may be appended to the tail end of ofpbuf + * 'b' before the ofpbuf must be reallocated. */ +size_t +ofpbuf_tailroom(struct ofpbuf *b) +{ + return (char*)ofpbuf_end(b) - (char*)ofpbuf_tail(b); +} + +/* Ensures that 'b' has room for at least 'size' bytes at its tail end, + * reallocating and copying its data if necessary. */ +void +ofpbuf_prealloc_tailroom(struct ofpbuf *b, size_t size) +{ + if (size > ofpbuf_tailroom(b)) { + size_t new_allocated = b->allocated + MAX(size, 64); + void *new_base = xmalloc(new_allocated); + uintptr_t base_delta = (char*)new_base - (char*)b->base; + memcpy(new_base, b->base, b->allocated); + free(b->base); + b->base = new_base; + b->allocated = new_allocated; + b->data = (char*)b->data + base_delta; + if (b->l2) { + b->l2 = (char*)b->l2 + base_delta; + } + if (b->l3) { + b->l3 = (char*)b->l3 + base_delta; + } + if (b->l4) { + b->l4 = (char*)b->l4 + base_delta; + } + if (b->l7) { + b->l7 = (char*)b->l7 + base_delta; + } + } +} + +void +ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size) +{ + assert(size <= ofpbuf_headroom(b)); +} + +/* Trims the size of 'b' to fit its actual content. */ +void +ofpbuf_trim(struct ofpbuf *b) +{ + /* XXX These could be supported, but the current client doesn't care. */ + assert(b->data == b->base); + assert(b->l2 == NULL && b->l3 == NULL && b->l4 == NULL && b->l7 == NULL); + if (b->allocated > b->size) { + b->base = b->data = xrealloc(b->base, b->size); + b->allocated = b->size; + } +} + +/* Appends 'size' bytes of data to the tail end of 'b', reallocating and + * copying its data if necessary. Returns a pointer to the first byte of the + * new data, which is left uninitialized. */ +void * +ofpbuf_put_uninit(struct ofpbuf *b, size_t size) +{ + void *p; + ofpbuf_prealloc_tailroom(b, size); + p = ofpbuf_tail(b); + b->size += size; + return p; +} + +/* Appends 'size' zeroed bytes to the tail end of 'b'. Data in 'b' is + * reallocated and copied if necessary. Returns a pointer to the first byte of + * the data's location in the ofpbuf. */ +void * +ofpbuf_put_zeros(struct ofpbuf *b, size_t size) +{ + void *dst = ofpbuf_put_uninit(b, size); + memset(dst, 0, size); + return dst; +} + +/* Appends the 'size' bytes of data in 'p' to the tail end of 'b'. Data in 'b' + * is reallocated and copied if necessary. Returns a pointer to the first + * byte of the data's location in the ofpbuf. */ +void * +ofpbuf_put(struct ofpbuf *b, const void *p, size_t size) +{ + void *dst = ofpbuf_put_uninit(b, size); + memcpy(dst, p, size); + return dst; +} + +/* Reserves 'size' bytes of headroom so that they can be later allocated with + * ofpbuf_push_uninit() without reallocating the ofpbuf. */ +void +ofpbuf_reserve(struct ofpbuf *b, size_t size) +{ + assert(!b->size); + ofpbuf_prealloc_tailroom(b, size); + b->data = (char*)b->data + size; +} + +void * +ofpbuf_push_uninit(struct ofpbuf *b, size_t size) +{ + ofpbuf_prealloc_headroom(b, size); + b->data = (char*)b->data - size; + b->size += size; + return b->data; +} + +void * +ofpbuf_push(struct ofpbuf *b, const void *p, size_t size) +{ + void *dst = ofpbuf_push_uninit(b, size); + memcpy(dst, p, size); + return dst; +} + +/* If 'b' contains at least 'offset + size' bytes of data, returns a pointer to + * byte 'offset'. Otherwise, returns a null pointer. */ +void * +ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size) +{ + return offset + size <= b->size ? (char *) b->data + offset : NULL; +} + +/* Returns a pointer to byte 'offset' in 'b', which must contain at least + * 'offset + size' bytes of data. */ +void * +ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size) +{ + assert(offset + size <= b->size); + return ((char *) b->data) + offset; +} + +/* Returns the byte following the last byte of data in use in 'b'. */ +void * +ofpbuf_tail(const struct ofpbuf *b) +{ + return (char *) b->data + b->size; +} + +/* Returns the byte following the last byte allocated for use (but not + * necessarily in use) by 'b'. */ +void * +ofpbuf_end(const struct ofpbuf *b) +{ + return (char *) b->base + b->allocated; +} + +/* Clears any data from 'b'. */ +void +ofpbuf_clear(struct ofpbuf *b) +{ + b->data = b->base; + b->size = 0; +} + +/* Removes 'size' bytes from the head end of 'b', which must contain at least + * 'size' bytes of data. Returns the first byte of data removed. */ +void * +ofpbuf_pull(struct ofpbuf *b, size_t size) +{ + void *data = b->data; + assert(b->size >= size); + b->data = (char*)b->data + size; + b->size -= size; + return data; +} + +/* If 'b' has at least 'size' bytes of data, removes that many bytes from the + * head end of 'b' and returns the first byte removed. Otherwise, returns a + * null pointer without modifying 'b'. */ +void * +ofpbuf_try_pull(struct ofpbuf *b, size_t size) +{ + return b->size >= size ? ofpbuf_pull(b, size) : NULL; +} |