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 } 86
