Initial checkin of gRPC to third_party/

third_party/grpc/src/core/support/slice.c

+/*
+ *
+ * Copyright 2015, 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);
+}