40 lines
1.2 KiB
Markdown
40 lines
1.2 KiB
Markdown
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# string
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C string helpers
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## Functions
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### find_substrings
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Finds the indexes of all locations of the given needle in the haystack. The returned array of `size_t` is allocated by
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this function and memory cleanup is managed by the user. `num_substrings` is a pointer to a pre-allocated `size_t` that will
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be modified to contain the number of found substrings and subsequently the size of the returned array of `size_t`.
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Returns `NULL` and prints to `stderr` if there is an error.
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```c
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size_t *find_substrings(const char* haystack, const char* needle, size_t *num_substrings);
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/* Usage */
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const char* haystack = "One two three two";
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const char* needle = "two";
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size_t subs_sz = 0;
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size_t *subs = find_substrings(haystack, needle, &subs_sz);
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// subs: [ 4, 14 ]
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// subs_sz: 2
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free(subs);
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```
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### substr
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Extracts a substring at a specific index and length. This function returns a copy of the substring in a heap allocated
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buffer that the user is responsible for freeing. Returns `NULL` and prints to `stderr` if there is an error.
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```c
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const char* substr(const char* str, size_t idx, size_t len);
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/* Usage */
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const char *s = substr("One two three", 4, 3);
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assert(strcmp(s, "two") == 0);
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free(s);
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```
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