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Add Str::replace(find, repl) function. #15

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Add Str::replace(find, repl) function. #15

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d6d1fd3
Add Str::replace(find, repl) function.
rokups Jun 16, 2021
39c8e1b
[SQUASH] Take ownership of non-owned string when replacing and fix al…
rokups Jun 18, 2021
e7f8701
[SQUASH] Attempt early out from replacement loop when possible.
rokups Jun 18, 2021
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51 changes: 51 additions & 0 deletions Str.h
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Original file line number Diff line number Diff line change
Expand Up @@ -161,6 +161,7 @@ class STR_API Str
int append_from(int idx, const char* s, const char* s_end = NULL); // If you know the string length or want to append from a certain point
int appendf_from(int idx, const char* fmt, ...);
int appendfv_from(int idx, const char* fmt, va_list args);
void replace(const char* find, const char* repl);

void clear();
void reserve(int cap);
Expand Down Expand Up @@ -651,6 +652,56 @@ int Str::appendf(const char* fmt, ...)
return len;
}

void Str::replace(const char* find, const char* repl)
{
STR_ASSERT(find != NULL && *find);
STR_ASSERT(repl != NULL);
int find_len = (int)strlen(find);
int repl_len = (int)strlen(repl);
int repl_diff = repl_len - find_len;

// Estimate required length of new buffer if string size increases.
int need_capacity = Capacity;
int num_matches = INT_MAX;
if (repl_diff > 0)
{
num_matches = 0;
need_capacity = length() + 1;
for (char* p = Data, *end = Data + length(); p != NULL && p < end;)
{
p = (char*)memmem(p, end - p, find, find_len);
if (p)
{
need_capacity += repl_diff;
p += find_len;
num_matches++;
}
}
}

if (num_matches == 0)
return;

const char* not_owned_data = Owned ? NULL : Data;
if (!Owned || need_capacity > Capacity)
reserve(need_capacity);
if (not_owned_data != NULL)
set(not_owned_data);

// Replace data.
for (char* p = Data, *end = Data + length(); p != NULL && p < end && num_matches--;)
{
p = (char*)memmem(p, end - p, find, find_len);
if (p)
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@ocornut ocornut Jun 16, 2021

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Maybe avoid looping fully if no match or end when last match?

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@rokups rokups Jun 18, 2021

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That was already the case. memmem() would return NULL and loop would not continue due to p != NULL check in for

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@ocornut ocornut Jun 18, 2021

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By definition if memmem returns null it means the string has been read entirely. Whereas you already have a match counter you can use to early out.

{
memmove(p + repl_len, p + find_len, end - p - find_len + 1);
memcpy(p, repl, repl_len);
p += repl_len;
end += repl_diff;
}
}
}

#endif // #define STR_IMPLEMENTATION

//-------------------------------------------------------------------------