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Diffstat (limited to 'src/core/lib/support/slice.c')
| -rw-r--r-- | src/core/lib/support/slice.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/src/core/lib/support/slice.c b/src/core/lib/support/slice.c new file mode 100644 index 0000000000..cf3953ce4e --- /dev/null +++ b/src/core/lib/support/slice.c @@ -0,0 +1,343 @@ +/* + * + * Copyright 2015-2016, Google Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT + * OWNER 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. + * + */ + +#include <grpc/support/alloc.h> +#include <grpc/support/log.h> +#include <grpc/support/slice.h> + +#include <string.h> + +gpr_slice gpr_empty_slice(void) { + gpr_slice out; + out.refcount = 0; + out.data.inlined.length = 0; + return out; +} + +gpr_slice gpr_slice_ref(gpr_slice slice) { + if (slice.refcount) { + slice.refcount->ref(slice.refcount); + } + return slice; +} + +void gpr_slice_unref(gpr_slice slice) { + if (slice.refcount) { + slice.refcount->unref(slice.refcount); + } +} + +/* gpr_slice_from_static_string support structure - a refcount that does + nothing */ +static void noop_ref_or_unref(void *unused) {} + +static gpr_slice_refcount noop_refcount = {noop_ref_or_unref, + noop_ref_or_unref}; + +gpr_slice gpr_slice_from_static_string(const char *s) { + gpr_slice slice; + slice.refcount = &noop_refcount; + slice.data.refcounted.bytes = (uint8_t *)s; + slice.data.refcounted.length = strlen(s); + return slice; +} + +/* gpr_slice_new support structures - we create a refcount object extended + with the user provided data pointer & destroy function */ +typedef struct new_slice_refcount { + gpr_slice_refcount rc; + gpr_refcount refs; + void (*user_destroy)(void *); + void *user_data; +} new_slice_refcount; + +static void new_slice_ref(void *p) { + new_slice_refcount *r = p; + gpr_ref(&r->refs); +} + +static void new_slice_unref(void *p) { + new_slice_refcount *r = p; + if (gpr_unref(&r->refs)) { + r->user_destroy(r->user_data); + gpr_free(r); + } +} + +gpr_slice gpr_slice_new(void *p, size_t len, void (*destroy)(void *)) { + gpr_slice slice; + new_slice_refcount *rc = gpr_malloc(sizeof(new_slice_refcount)); + gpr_ref_init(&rc->refs, 1); + rc->rc.ref = new_slice_ref; + rc->rc.unref = new_slice_unref; + rc->user_destroy = destroy; + rc->user_data = p; + + slice.refcount = &rc->rc; + slice.data.refcounted.bytes = p; + slice.data.refcounted.length = len; + return slice; +} + +/* gpr_slice_new_with_len support structures - we create a refcount object + extended with the user provided data pointer & destroy function */ +typedef struct new_with_len_slice_refcount { + gpr_slice_refcount rc; + gpr_refcount refs; + void *user_data; + size_t user_length; + void (*user_destroy)(void *, size_t); +} new_with_len_slice_refcount; + +static void new_with_len_ref(void *p) { + new_with_len_slice_refcount *r = p; + gpr_ref(&r->refs); +} + +static void new_with_len_unref(void *p) { + new_with_len_slice_refcount *r = p; + if (gpr_unref(&r->refs)) { + r->user_destroy(r->user_data, r->user_length); + gpr_free(r); + } +} + +gpr_slice gpr_slice_new_with_len(void *p, size_t len, + void (*destroy)(void *, size_t)) { + gpr_slice slice; + new_with_len_slice_refcount *rc = + gpr_malloc(sizeof(new_with_len_slice_refcount)); + gpr_ref_init(&rc->refs, 1); + rc->rc.ref = new_with_len_ref; + rc->rc.unref = new_with_len_unref; + rc->user_destroy = destroy; + rc->user_data = p; + rc->user_length = len; + + slice.refcount = &rc->rc; + slice.data.refcounted.bytes = p; + slice.data.refcounted.length = len; + return slice; +} + +gpr_slice gpr_slice_from_copied_buffer(const char *source, size_t length) { + gpr_slice slice = gpr_slice_malloc(length); + memcpy(GPR_SLICE_START_PTR(slice), source, length); + return slice; +} + +gpr_slice gpr_slice_from_copied_string(const char *source) { + return gpr_slice_from_copied_buffer(source, strlen(source)); +} + +typedef struct { + gpr_slice_refcount base; + gpr_refcount refs; +} malloc_refcount; + +static void malloc_ref(void *p) { + malloc_refcount *r = p; + gpr_ref(&r->refs); +} + +static void malloc_unref(void *p) { + malloc_refcount *r = p; + if (gpr_unref(&r->refs)) { + gpr_free(r); + } +} + +gpr_slice gpr_slice_malloc(size_t length) { + gpr_slice slice; + + if (length > sizeof(slice.data.inlined.bytes)) { + /* Memory layout used by the slice created here: + + +-----------+----------------------------------------------------------+ + | refcount | bytes | + +-----------+----------------------------------------------------------+ + + refcount is a malloc_refcount + bytes is an array of bytes of the requested length + Both parts are placed in the same allocation returned from gpr_malloc */ + malloc_refcount *rc = gpr_malloc(sizeof(malloc_refcount) + length); + + /* Initial refcount on rc is 1 - and it's up to the caller to release + this reference. */ + gpr_ref_init(&rc->refs, 1); + + rc->base.ref = malloc_ref; + rc->base.unref = malloc_unref; + + /* Build up the slice to be returned. */ + /* The slices refcount points back to the allocated block. */ + slice.refcount = &rc->base; + /* The data bytes are placed immediately after the refcount struct */ + slice.data.refcounted.bytes = (uint8_t *)(rc + 1); + /* And the length of the block is set to the requested length */ + slice.data.refcounted.length = length; + } else { + /* small slice: just inline the data */ + slice.refcount = NULL; + slice.data.inlined.length = (uint8_t)length; + } + return slice; +} + +gpr_slice gpr_slice_sub_no_ref(gpr_slice source, size_t begin, size_t end) { + gpr_slice subset; + + GPR_ASSERT(end >= begin); + + if (source.refcount) { + /* Enforce preconditions */ + GPR_ASSERT(source.data.refcounted.length >= end); + + /* Build the result */ + subset.refcount = source.refcount; + /* Point into the source array */ + subset.data.refcounted.bytes = source.data.refcounted.bytes + begin; + subset.data.refcounted.length = end - begin; + } else { + /* Enforce preconditions */ + GPR_ASSERT(source.data.inlined.length >= end); + subset.refcount = NULL; + subset.data.inlined.length = (uint8_t)(end - begin); + memcpy(subset.data.inlined.bytes, source.data.inlined.bytes + begin, + end - begin); + } + return subset; +} + +gpr_slice gpr_slice_sub(gpr_slice source, size_t begin, size_t end) { + gpr_slice subset; + + if (end - begin <= sizeof(subset.data.inlined.bytes)) { + subset.refcount = NULL; + subset.data.inlined.length = (uint8_t)(end - begin); + memcpy(subset.data.inlined.bytes, GPR_SLICE_START_PTR(source) + begin, + end - begin); + } else { + subset = gpr_slice_sub_no_ref(source, begin, end); + /* Bump the refcount */ + subset.refcount->ref(subset.refcount); + } + return subset; +} + +gpr_slice gpr_slice_split_tail(gpr_slice *source, size_t split) { + gpr_slice tail; + + if (source->refcount == NULL) { + /* inlined data, copy it out */ + GPR_ASSERT(source->data.inlined.length >= split); + tail.refcount = NULL; + tail.data.inlined.length = (uint8_t)(source->data.inlined.length - split); + memcpy(tail.data.inlined.bytes, source->data.inlined.bytes + split, + tail.data.inlined.length); + source->data.inlined.length = (uint8_t)split; + } else { + size_t tail_length = source->data.refcounted.length - split; + GPR_ASSERT(source->data.refcounted.length >= split); + if (tail_length < sizeof(tail.data.inlined.bytes)) { + /* Copy out the bytes - it'll be cheaper than refcounting */ + tail.refcount = NULL; + tail.data.inlined.length = (uint8_t)tail_length; + memcpy(tail.data.inlined.bytes, source->data.refcounted.bytes + split, + tail_length); + } else { + /* Build the result */ + tail.refcount = source->refcount; + /* Bump the refcount */ + tail.refcount->ref(tail.refcount); + /* Point into the source array */ + tail.data.refcounted.bytes = source->data.refcounted.bytes + split; + tail.data.refcounted.length = tail_length; + } + source->data.refcounted.length = split; + } + + return tail; +} + +gpr_slice gpr_slice_split_head(gpr_slice *source, size_t split) { + gpr_slice head; + + if (source->refcount == NULL) { + GPR_ASSERT(source->data.inlined.length >= split); + + head.refcount = NULL; + head.data.inlined.length = (uint8_t)split; + memcpy(head.data.inlined.bytes, source->data.inlined.bytes, split); + source->data.inlined.length = + (uint8_t)(source->data.inlined.length - split); + memmove(source->data.inlined.bytes, source->data.inlined.bytes + split, + source->data.inlined.length); + } else if (split < sizeof(head.data.inlined.bytes)) { + GPR_ASSERT(source->data.refcounted.length >= split); + + head.refcount = NULL; + head.data.inlined.length = (uint8_t)split; + memcpy(head.data.inlined.bytes, source->data.refcounted.bytes, split); + source->data.refcounted.bytes += split; + source->data.refcounted.length -= split; + } else { + GPR_ASSERT(source->data.refcounted.length >= split); + + /* Build the result */ + head.refcount = source->refcount; + /* Bump the refcount */ + head.refcount->ref(head.refcount); + /* Point into the source array */ + head.data.refcounted.bytes = source->data.refcounted.bytes; + head.data.refcounted.length = split; + source->data.refcounted.bytes += split; + source->data.refcounted.length -= split; + } + + return head; +} + +int gpr_slice_cmp(gpr_slice a, gpr_slice b) { + int d = (int)(GPR_SLICE_LENGTH(a) - GPR_SLICE_LENGTH(b)); + if (d != 0) return d; + return memcmp(GPR_SLICE_START_PTR(a), GPR_SLICE_START_PTR(b), + GPR_SLICE_LENGTH(a)); +} + +int gpr_slice_str_cmp(gpr_slice a, const char *b) { + size_t b_length = strlen(b); + int d = (int)(GPR_SLICE_LENGTH(a) - b_length); + if (d != 0) return d; + return memcmp(GPR_SLICE_START_PTR(a), b, b_length); +} |