1 // Copyright 2021 gRPC authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <grpc/support/port_platform.h>
16
17 #include "src/core/lib/slice/slice_split.h"
18
19 #include <string.h>
20
21 #include <grpc/support/log.h>
22
23 /** Finds the initial (\a begin) and final (\a end) offsets of the next
24 * substring from \a str + \a read_offset until the next \a sep or the end of \a
25 * str.
26 *
27 * Returns 1 and updates \a begin and \a end. Returns 0 otherwise. */
slice_find_separator_offset(const grpc_slice str,const char * sep,const size_t read_offset,size_t * begin,size_t * end)28 static int slice_find_separator_offset(const grpc_slice str, const char* sep,
29 const size_t read_offset, size_t* begin,
30 size_t* end) {
31 size_t i;
32 const uint8_t* str_ptr = GRPC_SLICE_START_PTR(str) + read_offset;
33 const size_t str_len = GRPC_SLICE_LENGTH(str) - read_offset;
34 const size_t sep_len = strlen(sep);
35 if (str_len < sep_len) {
36 return 0;
37 }
38
39 for (i = 0; i <= str_len - sep_len; i++) {
40 if (memcmp(str_ptr + i, sep, sep_len) == 0) {
41 *begin = read_offset;
42 *end = read_offset + i;
43 return 1;
44 }
45 }
46 return 0;
47 }
48
skip_leading_trailing_spaces(const uint8_t * str_buffer,size_t * begin,size_t * end)49 static void skip_leading_trailing_spaces(const uint8_t* str_buffer,
50 size_t* begin, size_t* end) {
51 while (*begin < *end && str_buffer[*begin] == ' ') {
52 (*begin)++;
53 }
54 while (*begin < *end && str_buffer[*end - 1] == ' ') {
55 (*end)--;
56 }
57 }
58
grpc_slice_split_inner(grpc_slice str,const char * sep,grpc_slice_buffer * dst,bool no_space)59 static void grpc_slice_split_inner(grpc_slice str, const char* sep,
60 grpc_slice_buffer* dst, bool no_space) {
61 const size_t sep_len = strlen(sep);
62 size_t begin, end;
63 const uint8_t* str_buffer = GRPC_SLICE_START_PTR(str);
64 size_t sep_pos;
65
66 GPR_ASSERT(sep_len > 0);
67
68 if (slice_find_separator_offset(str, sep, 0, &begin, &end) != 0) {
69 do {
70 sep_pos = end;
71 if (no_space) {
72 skip_leading_trailing_spaces(str_buffer, &begin, &end);
73 }
74 grpc_slice_buffer_add_indexed(dst, grpc_slice_sub(str, begin, end));
75 } while (slice_find_separator_offset(str, sep, sep_pos + sep_len, &begin,
76 &end) != 0);
77 begin = sep_pos + sep_len;
78 end = GRPC_SLICE_LENGTH(str);
79 if (no_space) {
80 skip_leading_trailing_spaces(str_buffer, &begin, &end);
81 }
82 grpc_slice_buffer_add_indexed(dst, grpc_slice_sub(str, begin, end));
83 } else { /* no sep found, add whole input */
84 begin = 0;
85 end = GRPC_SLICE_LENGTH(str);
86 if (no_space) {
87 skip_leading_trailing_spaces(str_buffer, &begin, &end);
88 }
89 grpc_slice_buffer_add_indexed(dst, grpc_slice_sub(str, begin, end));
90 }
91 }
92
grpc_slice_split(grpc_slice str,const char * sep,grpc_slice_buffer * dst)93 void grpc_slice_split(grpc_slice str, const char* sep, grpc_slice_buffer* dst) {
94 grpc_slice_split_inner(str, sep, dst, false);
95 }
96
grpc_slice_split_without_space(grpc_slice str,const char * sep,grpc_slice_buffer * dst)97 void grpc_slice_split_without_space(grpc_slice str, const char* sep,
98 grpc_slice_buffer* dst) {
99 grpc_slice_split_inner(str, sep, dst, true);
100 }
101