1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "include/ese/ese.h"
18
min_u32(uint32_t a,uint32_t b)19 static inline uint32_t min_u32(uint32_t a, uint32_t b) { return a < b ? a : b; }
20
ese_sg_length(const struct EseSgBuffer * bufs,uint32_t cnt)21 ESE_API uint32_t ese_sg_length(const struct EseSgBuffer *bufs, uint32_t cnt) {
22 const struct EseSgBuffer *buf = bufs;
23 uint32_t len = 0;
24 if (!bufs || cnt == 0) {
25 return 0;
26 }
27 while (buf < bufs + cnt) {
28 /* In reality, this is probably corruption or a mistake. */
29 if (ESE_UINT32_MAX - len < buf->len) {
30 return ESE_UINT32_MAX;
31 }
32 len += buf->len;
33 buf++;
34 }
35 return len;
36 }
37
ese_sg_to_buf(const struct EseSgBuffer * src,uint32_t src_cnt,uint32_t start_at,uint32_t length,uint8_t * dst)38 ESE_API uint32_t ese_sg_to_buf(const struct EseSgBuffer *src, uint32_t src_cnt,
39 uint32_t start_at, uint32_t length,
40 uint8_t *dst) {
41 const struct EseSgBuffer *buf = src;
42 uint32_t remaining = length;
43 if (!src || src_cnt == 0) {
44 return 0;
45 }
46 while (remaining && buf < src + src_cnt) {
47 if (start_at > buf->len) {
48 start_at -= buf->len;
49 buf++;
50 continue;
51 }
52 uint32_t copy_len = min_u32(remaining, buf->len - start_at);
53 ese_memcpy(dst, buf->c_base + start_at, copy_len);
54 dst += copy_len;
55 remaining -= copy_len;
56 start_at = 0;
57 buf++;
58 }
59 return length - remaining;
60 }
61
ese_sg_from_buf(struct EseSgBuffer * dst,uint32_t dst_cnt,uint32_t start_at,uint32_t length,const uint8_t * src)62 ESE_API uint32_t ese_sg_from_buf(struct EseSgBuffer *dst, uint32_t dst_cnt,
63 uint32_t start_at, uint32_t length,
64 const uint8_t *src) {
65 const struct EseSgBuffer *buf = dst;
66 uint32_t remaining = length;
67 if (!dst || dst_cnt == 0) {
68 return 0;
69 }
70
71 while (remaining && buf < dst + dst_cnt) {
72 if (start_at >= buf->len) {
73 start_at -= buf->len;
74 buf++;
75 continue;
76 }
77 uint32_t copy_len = min_u32(remaining, buf->len - start_at);
78 ese_memcpy(buf->base + start_at, src, copy_len);
79 src += copy_len;
80 remaining -= copy_len;
81 start_at = 0;
82 buf++;
83 }
84 return length - remaining;
85 }
86