1 files changed, 284 insertions, 0 deletions

diff --git a/src/core/lib/slice/slice_buffer.c b/src/core/lib/slice/slice_buffer.c
new file mode 100644
index 0000000000..990ef128bd
--- /dev/null
+++ b/src/core/lib/slice/slice_buffer.c
@@ -0,0 +1,284 @@
+/*
+ *
+ * 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/slice_buffer.h>
+#include <grpc/support/port_platform.h>
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/useful.h>
+
+/* grow a buffer; requires GRPC_SLICE_BUFFER_INLINE_ELEMENTS > 1 */
+#define GROW(x) (3 * (x) / 2)
+
+static void maybe_embiggen(grpc_slice_buffer *sb) {
+  if (sb->count == sb->capacity) {
+    sb->capacity = GROW(sb->capacity);
+    GPR_ASSERT(sb->capacity > sb->count);
+    if (sb->slices == sb->inlined) {
+      sb->slices = gpr_malloc(sb->capacity * sizeof(grpc_slice));
+      memcpy(sb->slices, sb->inlined, sb->count * sizeof(grpc_slice));
+    } else {
+      sb->slices = gpr_realloc(sb->slices, sb->capacity * sizeof(grpc_slice));
+    }
+  }
+}
+
+void grpc_slice_buffer_init(grpc_slice_buffer *sb) {
+  sb->count = 0;
+  sb->length = 0;
+  sb->capacity = GRPC_SLICE_BUFFER_INLINE_ELEMENTS;
+  sb->slices = sb->inlined;
+}
+
+void grpc_slice_buffer_destroy(grpc_slice_buffer *sb) {
+  grpc_slice_buffer_reset_and_unref(sb);
+  if (sb->slices != sb->inlined) {
+    gpr_free(sb->slices);
+  }
+}
+
+uint8_t *grpc_slice_buffer_tiny_add(grpc_slice_buffer *sb, size_t n) {
+  grpc_slice *back;
+  uint8_t *out;
+
+  sb->length += n;
+
+  if (sb->count == 0) goto add_new;
+  back = &sb->slices[sb->count - 1];
+  if (back->refcount) goto add_new;
+  if ((back->data.inlined.length + n) > sizeof(back->data.inlined.bytes))
+    goto add_new;
+  out = back->data.inlined.bytes + back->data.inlined.length;
+  back->data.inlined.length = (uint8_t)(back->data.inlined.length + n);
+  return out;
+
+add_new:
+  maybe_embiggen(sb);
+  back = &sb->slices[sb->count];
+  sb->count++;
+  back->refcount = NULL;
+  back->data.inlined.length = (uint8_t)n;
+  return back->data.inlined.bytes;
+}
+
+size_t grpc_slice_buffer_add_indexed(grpc_slice_buffer *sb, grpc_slice s) {
+  size_t out = sb->count;
+  maybe_embiggen(sb);
+  sb->slices[out] = s;
+  sb->length += GRPC_SLICE_LENGTH(s);
+  sb->count = out + 1;
+  return out;
+}
+
+void grpc_slice_buffer_add(grpc_slice_buffer *sb, grpc_slice s) {
+  size_t n = sb->count;
+  /* if both the last slice in the slice buffer and the slice being added
+     are inlined (that is, that they carry their data inside the slice data
+     structure), and the back slice is not full, then concatenate directly
+     into the back slice, preventing many small slices being passed into
+     writes */
+  if (!s.refcount && n) {
+    grpc_slice *back = &sb->slices[n - 1];
+    if (!back->refcount &&
+        back->data.inlined.length < GRPC_SLICE_INLINED_SIZE) {
+      if (s.data.inlined.length + back->data.inlined.length <=
+          GRPC_SLICE_INLINED_SIZE) {
+        memcpy(back->data.inlined.bytes + back->data.inlined.length,
+               s.data.inlined.bytes, s.data.inlined.length);
+        back->data.inlined.length =
+            (uint8_t)(back->data.inlined.length + s.data.inlined.length);
+      } else {
+        size_t cp1 = GRPC_SLICE_INLINED_SIZE - back->data.inlined.length;
+        memcpy(back->data.inlined.bytes + back->data.inlined.length,
+               s.data.inlined.bytes, cp1);
+        back->data.inlined.length = GRPC_SLICE_INLINED_SIZE;
+        maybe_embiggen(sb);
+        back = &sb->slices[n];
+        sb->count = n + 1;
+        back->refcount = NULL;
+        back->data.inlined.length = (uint8_t)(s.data.inlined.length - cp1);
+        memcpy(back->data.inlined.bytes, s.data.inlined.bytes + cp1,
+               s.data.inlined.length - cp1);
+      }
+      sb->length += s.data.inlined.length;
+      return; /* early out */
+    }
+  }
+  grpc_slice_buffer_add_indexed(sb, s);
+}
+
+void grpc_slice_buffer_addn(grpc_slice_buffer *sb, grpc_slice *s, size_t n) {
+  size_t i;
+  for (i = 0; i < n; i++) {
+    grpc_slice_buffer_add(sb, s[i]);
+  }
+}
+
+void grpc_slice_buffer_pop(grpc_slice_buffer *sb) {
+  if (sb->count != 0) {
+    size_t count = --sb->count;
+    sb->length -= GRPC_SLICE_LENGTH(sb->slices[count]);
+  }
+}
+
+void grpc_slice_buffer_reset_and_unref(grpc_slice_buffer *sb) {
+  size_t i;
+
+  for (i = 0; i < sb->count; i++) {
+    grpc_slice_unref(sb->slices[i]);
+  }
+
+  sb->count = 0;
+  sb->length = 0;
+}
+
+void grpc_slice_buffer_swap(grpc_slice_buffer *a, grpc_slice_buffer *b) {
+  GPR_SWAP(size_t, a->count, b->count);
+  GPR_SWAP(size_t, a->capacity, b->capacity);
+  GPR_SWAP(size_t, a->length, b->length);
+
+  if (a->slices == a->inlined) {
+    if (b->slices == b->inlined) {
+      /* swap contents of inlined buffer */
+      grpc_slice temp[GRPC_SLICE_BUFFER_INLINE_ELEMENTS];
+      memcpy(temp, a->slices, b->count * sizeof(grpc_slice));
+      memcpy(a->slices, b->slices, a->count * sizeof(grpc_slice));
+      memcpy(b->slices, temp, b->count * sizeof(grpc_slice));
+    } else {
+      /* a is inlined, b is not - copy a inlined into b, fix pointers */
+      a->slices = b->slices;
+      b->slices = b->inlined;
+      memcpy(b->slices, a->inlined, b->count * sizeof(grpc_slice));
+    }
+  } else if (b->slices == b->inlined) {
+    /* b is inlined, a is not - copy b inlined int a, fix pointers */
+    b->slices = a->slices;
+    a->slices = a->inlined;
+    memcpy(a->slices, b->inlined, a->count * sizeof(grpc_slice));
+  } else {
+    /* no inlining: easy swap */
+    GPR_SWAP(grpc_slice *, a->slices, b->slices);
+  }
+}
+
+void grpc_slice_buffer_move_into(grpc_slice_buffer *src,
+                                 grpc_slice_buffer *dst) {
+  /* anything to move? */
+  if (src->count == 0) {
+    return;
+  }
+  /* anything in dst? */
+  if (dst->count == 0) {
+    grpc_slice_buffer_swap(src, dst);
+    return;
+  }
+  /* both buffers have data - copy, and reset src */
+  grpc_slice_buffer_addn(dst, src->slices, src->count);
+  src->count = 0;
+  src->length = 0;
+}
+
+void grpc_slice_buffer_move_first(grpc_slice_buffer *src, size_t n,
+                                  grpc_slice_buffer *dst) {
+  size_t src_idx;
+  size_t output_len = dst->length + n;
+  size_t new_input_len = src->length - n;
+  GPR_ASSERT(src->length >= n);
+  if (src->length == n) {
+    grpc_slice_buffer_move_into(src, dst);
+    return;
+  }
+  src_idx = 0;
+  while (src_idx < src->capacity) {
+    grpc_slice slice = src->slices[src_idx];
+    size_t slice_len = GRPC_SLICE_LENGTH(slice);
+    if (n > slice_len) {
+      grpc_slice_buffer_add(dst, slice);
+      n -= slice_len;
+      src_idx++;
+    } else if (n == slice_len) {
+      grpc_slice_buffer_add(dst, slice);
+      src_idx++;
+      break;
+    } else { /* n < slice_len */
+      src->slices[src_idx] = grpc_slice_split_tail(&slice, n);
+      GPR_ASSERT(GRPC_SLICE_LENGTH(slice) == n);
+      GPR_ASSERT(GRPC_SLICE_LENGTH(src->slices[src_idx]) == slice_len - n);
+      grpc_slice_buffer_add(dst, slice);
+      break;
+    }
+  }
+  GPR_ASSERT(dst->length == output_len);
+  memmove(src->slices, src->slices + src_idx,
+          sizeof(grpc_slice) * (src->count - src_idx));
+  src->count -= src_idx;
+  src->length = new_input_len;
+  GPR_ASSERT(src->count > 0);
+}
+
+void grpc_slice_buffer_trim_end(grpc_slice_buffer *sb, size_t n,
+                                grpc_slice_buffer *garbage) {
+  GPR_ASSERT(n <= sb->length);
+  sb->length -= n;
+  for (;;) {
+    size_t idx = sb->count - 1;
+    grpc_slice slice = sb->slices[idx];
+    size_t slice_len = GRPC_SLICE_LENGTH(slice);
+    if (slice_len > n) {
+      sb->slices[idx] = grpc_slice_split_head(&slice, slice_len - n);
+      grpc_slice_buffer_add_indexed(garbage, slice);
+      return;
+    } else if (slice_len == n) {
+      grpc_slice_buffer_add_indexed(garbage, slice);
+      sb->count = idx;
+      return;
+    } else {
+      grpc_slice_buffer_add_indexed(garbage, slice);
+      n -= slice_len;
+      sb->count = idx;
+    }
+  }
+}
+
+grpc_slice grpc_slice_buffer_take_first(grpc_slice_buffer *sb) {
+  grpc_slice slice;
+  GPR_ASSERT(sb->count > 0);
+  slice = sb->slices[0];
+  memmove(&sb->slices[0], &sb->slices[1], (sb->count - 1) * sizeof(grpc_slice));
+  sb->count--;
+  sb->length -= GRPC_SLICE_LENGTH(slice);
+  return slice;
+}