1 /*
2 * Copyright (c) 2009-2022, Google LLC
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Google LLC nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "upb/io/chunked_output_stream.h"
29
30 // Must be last.
31 #include "upb/port/def.inc"
32
33 typedef struct {
34 upb_ZeroCopyOutputStream base;
35
36 char* data;
37 size_t size;
38 size_t limit;
39 size_t position;
40 size_t last_returned_size;
41 } upb_ChunkedOutputStream;
42
upb_ChunkedOutputStream_Next(upb_ZeroCopyOutputStream * z,size_t * count,upb_Status * status)43 static void* upb_ChunkedOutputStream_Next(upb_ZeroCopyOutputStream* z,
44 size_t* count, upb_Status* status) {
45 upb_ChunkedOutputStream* c = (upb_ChunkedOutputStream*)z;
46 UPB_ASSERT(c->position <= c->size);
47
48 char* out = c->data + c->position;
49
50 const size_t chunk = UPB_MIN(c->limit, c->size - c->position);
51 c->position += chunk;
52 c->last_returned_size = chunk;
53 *count = chunk;
54
55 return chunk ? out : NULL;
56 }
57
upb_ChunkedOutputStream_BackUp(upb_ZeroCopyOutputStream * z,size_t count)58 static void upb_ChunkedOutputStream_BackUp(upb_ZeroCopyOutputStream* z,
59 size_t count) {
60 upb_ChunkedOutputStream* c = (upb_ChunkedOutputStream*)z;
61
62 UPB_ASSERT(c->last_returned_size >= count);
63 c->position -= count;
64 c->last_returned_size -= count;
65 }
66
upb_ChunkedOutputStream_ByteCount(const upb_ZeroCopyOutputStream * z)67 static size_t upb_ChunkedOutputStream_ByteCount(
68 const upb_ZeroCopyOutputStream* z) {
69 const upb_ChunkedOutputStream* c = (const upb_ChunkedOutputStream*)z;
70
71 return c->position;
72 }
73
74 static const _upb_ZeroCopyOutputStream_VTable upb_ChunkedOutputStream_vtable = {
75 upb_ChunkedOutputStream_Next,
76 upb_ChunkedOutputStream_BackUp,
77 upb_ChunkedOutputStream_ByteCount,
78 };
79
upb_ChunkedOutputStream_New(void * data,size_t size,size_t limit,upb_Arena * arena)80 upb_ZeroCopyOutputStream* upb_ChunkedOutputStream_New(void* data, size_t size,
81 size_t limit,
82 upb_Arena* arena) {
83 upb_ChunkedOutputStream* c = upb_Arena_Malloc(arena, sizeof(*c));
84 if (!c || !limit) return NULL;
85
86 c->base.vtable = &upb_ChunkedOutputStream_vtable;
87 c->data = data;
88 c->size = size;
89 c->limit = limit;
90 c->position = 0;
91 c->last_returned_size = 0;
92
93 return (upb_ZeroCopyOutputStream*)c;
94 }
95