F´ Flight Software - C/C++ Documentation  devel
A framework for building embedded system applications to NASA flight quality standards.
StringUtils.cpp
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1 #include "StringUtils.hpp"
2 #include <Fw/Types/Assert.hpp>
3 #include <cstring>
4 #include <limits>
5 
6 char* Fw::StringUtils::string_copy(char* destination, const char* source, FwSizeType num) {
7  // Handle self-copy and 0 bytes copy
8  if (destination == source || num == 0) {
9  return destination;
10  }
11  FW_ASSERT(source != nullptr);
12  FW_ASSERT(destination != nullptr);
13 
14  // Copying an overlapping range is undefined
15  FwSizeType source_len = string_length(source, num) + 1;
16  FW_ASSERT(source + source_len <= destination || destination + num <= source);
17 
18  char* returned = strncpy(destination, source, num);
19  destination[num - 1] = '\0';
20  return returned;
21 }
22 
24  FwSizeType length = 0;
25  FW_ASSERT(source != nullptr);
26  for (length = 0; length < buffer_size; length++) {
27  if (source[length] == '\0') {
28  break;
29  }
30  }
31  return length;
32 }
33 
35  FwSizeType source_size,
36  const CHAR* sub_string,
37  FwSizeType sub_size) {
38  FW_ASSERT(source_string != nullptr);
39  FW_ASSERT(sub_string != nullptr);
40 
41  // zero size sub-strings should always match
42  if ((source_size > 0) && (0 == sub_size)) {
43  return 0;
44  }
45 
46  // Cannot find a substring larger than the source
47  if (source_size < sub_size) {
48  return -1;
49  }
50  // Confirm that the output type can hold the range of valid results
51  FW_ASSERT(static_cast<FwSignedSizeType>(source_size - sub_size) <= std::numeric_limits<FwSignedSizeType>::max());
52 
53  // Loop from zero to source_size - sub_size (inclusive)
54  for (FwSizeType source_index = 0;
55  source_index < (source_size - sub_size + 1) &&
56  source_index < static_cast<FwSizeType>(std::numeric_limits<FwSignedSizeType>::max());
57  source_index++) {
58  // if the current character matches
59  for (FwSizeType sub_index = 0; sub_index < sub_size; sub_index++) {
60  // Prevent read overrun
61  FW_ASSERT((source_index + sub_index) < source_size);
62  // if there is a mismatch, go to next character
63  if (source_string[source_index + sub_index] != sub_string[sub_index]) {
64  break;
65  } else if (sub_index == (sub_size - 1)) {
66  // if we matched all the way to the end of the substring
67  return static_cast<FwSignedSizeType>(source_index);
68  }
69  }
70  }
71 
72  // if we make it here, no matches were found
73  return -1;
74 }
#define FW_ASSERT(...)
Definition: Assert.hpp:14
char CHAR
Definition: BasicTypes.h:32
PlatformSignedSizeType FwSignedSizeType
Definition: FpConfig.h:30
PlatformSizeType FwSizeType
Definition: FpConfig.h:35
FwSizeType string_length(const CHAR *source, FwSizeType buffer_size)
get the length of the source string
Definition: StringUtils.cpp:23
char * string_copy(char *destination, const char *source, FwSizeType num)
copy string with null-termination guaranteed
Definition: StringUtils.cpp:6
FwSignedSizeType substring_find(const CHAR *source_string, FwSizeType source_size, const CHAR *sub_string, FwSizeType sub_size)
find the first occurrence of a substring
Definition: StringUtils.cpp:34