Will Drewry | 8f367fc | 2017-03-30 22:07:48 -0500 | [diff] [blame] | 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 | |
| 19 | static inline uint32_t min_u32(uint32_t a, uint32_t b) { return a < b ? a : b; } |
| 20 | |
| 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 | |
| 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 | |
| 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 | } |