X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fofpbuf.c;h=6484ab3b86d534b630c8c2becea303cea7fa8676;hb=eb857b4824d2a62e1cc1b85c30a3da007d4942c9;hp=34aad93825126943d4ffbaaaf9be9a8aa2d2b677;hpb=a46c577af5c5855939ca3192a56396e15bebf0f8;p=sliver-openvswitch.git diff --git a/lib/ofpbuf.c b/lib/ofpbuf.c index 34aad9382..6484ab3b8 100644 --- a/lib/ofpbuf.c +++ b/lib/ofpbuf.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -16,7 +16,6 @@ #include #include "ofpbuf.h" -#include #include #include #include "dynamic-string.h" @@ -47,23 +46,44 @@ ofpbuf_use(struct ofpbuf *b, void *base, size_t allocated) /* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of * memory starting at 'base'. 'base' should point to a buffer on the stack. - * If 'b' is resized, new memory will be allocated with malloc() and 'base' - * will not be freed. This is useful when a small stack-allocated buffer is - * normally appropriate but sometimes it must be expanded. + * (Nothing actually relies on 'base' being allocated on the stack. It could + * be static or malloc()'d memory. But stack space is the most common use + * case.) * * 'base' should be appropriately aligned. Using an array of uint32_t or * uint64_t for the buffer is a reasonable way to ensure appropriate alignment - * for 32- or 64-bit data. + * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so. * - * (Nothing actually relies on 'base' being allocated on the stack. It could - * be static or malloc()'d memory. But stack space is the most common use - * case.) */ + * An ofpbuf operation that requires reallocating data will assert-fail if this + * function was used to initialize it. Thus, one need not call ofpbuf_uninit() + * on an ofpbuf initialized by this function (though doing so is harmless), + * because it is guaranteed that 'b' does not own any heap-allocated memory. */ void ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated) { ofpbuf_use__(b, base, allocated, OFPBUF_STACK); } +/* Initializes 'b' as an empty ofpbuf that contains the 'allocated' bytes of + * memory starting at 'base'. 'base' should point to a buffer on the stack. + * (Nothing actually relies on 'base' being allocated on the stack. It could + * be static or malloc()'d memory. But stack space is the most common usen + * case.) + * + * 'base' should be appropriately aligned. Using an array of uint32_t or + * uint64_t for the buffer is a reasonable way to ensure appropriate alignment + * for 32- or 64-bit data. OFPBUF_STACK_BUFFER is a convenient way to do so. + * + * An ofpbuf operation that requires reallocating data will copy the provided + * buffer into a malloc()'d buffer. Thus, it is wise to call ofpbuf_uninit() + * on an ofpbuf initialized by this function, so that if it expanded into the + * heap, that memory is freed. */ +void +ofpbuf_use_stub(struct ofpbuf *b, void *base, size_t allocated) +{ + ofpbuf_use__(b, base, allocated, OFPBUF_STUB); +} + /* Initializes 'b' as an ofpbuf whose data starts at 'data' and continues for * 'size' bytes. This is appropriate for an ofpbuf that will be used to * inspect existing data, without moving it around or reallocating it, and @@ -74,7 +94,7 @@ ofpbuf_use_stack(struct ofpbuf *b, void *base, size_t allocated) void ofpbuf_use_const(struct ofpbuf *b, const void *data, size_t size) { - ofpbuf_use__(b, (void *) data, size, OFPBUF_CONST); + ofpbuf_use__(b, CONST_CAST(void *, data), size, OFPBUF_STACK); b->size = size; } @@ -95,6 +115,15 @@ ofpbuf_uninit(struct ofpbuf *b) } } +/* Returns a pointer that may be passed to free() to accomplish the same thing + * as ofpbuf_uninit(b). The return value is a null pointer if ofpbuf_uninit() + * would not free any memory. */ +void * +ofpbuf_get_uninit_pointer(struct ofpbuf *b) +{ + return b && b->source == OFPBUF_MALLOC ? b->base : NULL; +} + /* Frees memory that 'b' points to and allocates a new ofpbuf */ void ofpbuf_reinit(struct ofpbuf *b, size_t size) @@ -129,7 +158,7 @@ ofpbuf_new_with_headroom(size_t size, size_t headroom) struct ofpbuf * ofpbuf_clone(const struct ofpbuf *buffer) { - return ofpbuf_clone_data(buffer->data, buffer->size); + return ofpbuf_clone_with_headroom(buffer, 0); } /* Creates and returns a new ofpbuf whose data are copied from 'buffer'. The @@ -137,8 +166,27 @@ ofpbuf_clone(const struct ofpbuf *buffer) struct ofpbuf * ofpbuf_clone_with_headroom(const struct ofpbuf *buffer, size_t headroom) { - return ofpbuf_clone_data_with_headroom(buffer->data, buffer->size, - headroom); + struct ofpbuf *new_buffer; + uintptr_t data_delta; + + new_buffer = ofpbuf_clone_data_with_headroom(buffer->data, buffer->size, + headroom); + data_delta = (char *) new_buffer->data - (char *) buffer->data; + + if (buffer->l2) { + new_buffer->l2 = (char *) buffer->l2 + data_delta; + } + if (buffer->l3) { + new_buffer->l3 = (char *) buffer->l3 + data_delta; + } + if (buffer->l4) { + new_buffer->l4 = (char *) buffer->l4 + data_delta; + } + if (buffer->l7) { + new_buffer->l7 = (char *) buffer->l7 + data_delta; + } + + return new_buffer; } /* Creates and returns a new ofpbuf that initially contains a copy of the @@ -225,14 +273,14 @@ ofpbuf_resize__(struct ofpbuf *b, size_t new_headroom, size_t new_tailroom) break; case OFPBUF_STACK: + NOT_REACHED(); + + case OFPBUF_STUB: + b->source = OFPBUF_MALLOC; new_base = xmalloc(new_allocated); ofpbuf_copy__(b, new_base, new_headroom, new_tailroom); - b->source = OFPBUF_MALLOC; break; - case OFPBUF_CONST: - NOT_REACHED(); - default: NOT_REACHED(); } @@ -295,6 +343,16 @@ ofpbuf_trim(struct ofpbuf *b) } } +/* If 'b' is shorter than 'length' bytes, pads its tail out with zeros to that + * length. */ +void +ofpbuf_padto(struct ofpbuf *b, size_t length) +{ + if (b->size < length) { + ofpbuf_put_zeros(b, length - 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. */ @@ -349,7 +407,7 @@ ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n) if (n) { *n = b->size - initial_size; } - return (char *) s; + return CONST_CAST(char *, s); } ofpbuf_put(b, &byte, 1); @@ -362,7 +420,7 @@ ofpbuf_put_hex(struct ofpbuf *b, const char *s, size_t *n) void ofpbuf_reserve(struct ofpbuf *b, size_t size) { - assert(!b->size); + ovs_assert(!b->size); ofpbuf_prealloc_tailroom(b, size); b->data = (char*)b->data + size; } @@ -414,7 +472,7 @@ ofpbuf_at(const struct ofpbuf *b, size_t offset, size_t size) void * ofpbuf_at_assert(const struct ofpbuf *b, size_t offset, size_t size) { - assert(offset + size <= b->size); + ovs_assert(offset + size <= b->size); return ((char *) b->data) + offset; } @@ -447,7 +505,7 @@ void * ofpbuf_pull(struct ofpbuf *b, size_t size) { void *data = b->data; - assert(b->size >= size); + ovs_assert(b->size >= size); b->data = (char*)b->data + size; b->size -= size; return data; @@ -462,6 +520,25 @@ ofpbuf_try_pull(struct ofpbuf *b, size_t size) return b->size >= size ? ofpbuf_pull(b, size) : NULL; } +/* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer + * within 'b'. (If 'b' itself was dynamically allocated, e.g. with + * ofpbuf_new(), then it should still be freed with, e.g., ofpbuf_delete().) */ +void * +ofpbuf_steal_data(struct ofpbuf *b) +{ + void *p; + if (b->source == OFPBUF_MALLOC && b->data == b->base) { + p = b->data; + } else { + p = xmemdup(b->data, b->size); + if (b->source == OFPBUF_MALLOC) { + free(b->base); + } + } + b->base = b->data = NULL; + return p; +} + /* Returns a string that describes some of 'b''s metadata plus a hex dump of up * to 'maxbytes' from the start of the buffer. */ char *