cpp
/
EAStdC
mirror of https://github.com/electronicarts/EAStdC.git


			
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<Title>EAString</title>

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<h1>EAString</h1>

<h2>Introduction</h2>
<p>EAString implements an extensive suite of C string functionality from &lt;string.h&gt; in a portable way. Much of this functionality is the same as what 
    is present in the C standard and in common (but non-portable) extensions to the C standard. EAString presents a consistent portable interface to its functionality 
    in both 8 bit and 16 bit string form.</p>
<p>The C language provides various functions which work with non-portable data types, such as long. EAString defines all significant data types in terms of portable 
    types such as int32_t and int64_t. Additionally, the EAString versions of functions are usually faster than the C runtime library versions, usually because the EAString versions minimize cache misses 
    and branching, whereas typical C runtime libraries optimize for the smallest memory footprint with little or no regard to other performance characteristics. Also, the EAString functions do not implement locale-specific functionality and thus save time and space as a result. Other packages within EA implement localization functionality in a way that is better suited to high performance game development.</p>
<p>C-style printf functionality is separate from EAString and is found in <a href="EASprintf.html">EASprintf</a>. Memcpy functionality (which comes from the  &lt;string.h&gt; 
    header file) is present in <a href="EAMemory.html">EAMemory</a>. </p>
<h2>Extension functions</h2>
<p> EAString provides extended functionality that isn't found in conventional C libraries, but it useful nevertheless.</p>
<table width="100%" border="1" cellpadding="3">
    <tr> 
        <td><b>Function</b></td>
        <td><b>Description</b></td>
        <td><b>Signature</b></td>
    </tr>
    <tr> 
        <td>Strlcat</td>
        <td>Safe variation of strncat</td>
        <td><font size="-1">char_t* Strlcat(char_t* pDestination, const char_t* pSource, size_t n); </font></td>
    </tr>
    <tr> 
        <td>Strlcpy</td>
        <td>Safe variation of strcpy</td>
        <td><p><font size="-1">char_t* Strlcpy(char_t* pDestination, const char_t* pSource, size_t n); <br>
        int Strlcpy(char16_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char32_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char8_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char32_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char8_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char16_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0); <br>
        int Strlcpy(char8_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(char16_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0); <br>
        int Strlcpy(char32_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(wchar_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        int Strlcpy(wchar_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0); <br>
        int Strlcpy(wchar_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);<br>
        bool Strlcpy(char16_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char32_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char8_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char32_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char8_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char16_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char8_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char16_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(char32_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(wchar_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(wchar_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);<br>
        bool Strlcpy(wchar_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
        </font></p>
        </td>
    </tr>
    <tr> 
        <td>Stristr</td>
        <td>Case insensitive version of strstr (find string within string)</td>
        <td><font size="-1">char_t* Stristr(const char_t* pString, const char_t* pSubString);</font></td>
    </tr>
    <tr> 
        <td>FtoaEnglish</td>
        <td> 
            <p>Float to ascii; always use English numeric format, regardless of the current locale.</p>
        </td>
        <td><font size="-1">char_t* FtoaEnglish(double dValue, char_t* pResult, int nInputLength, int nPrecision, bool bExponentEnabled); </font></td>
    </tr>
    <tr> 
        <td>AtofEnglish</td>
        <td>Ascii to float; always use English numeric format, regardless of the current locale.</td>
        <td><font size="-1">double AtofEnglish(const char_t* pString); </font></td>
    </tr>
    <tr> 
        <td> StrtodEnglish</td>
        <td>Same as strtod, but always use English numeric format, regardless of the current locale.</td>
        <td><font size="-1">double StrtodEnglish(const char_t* pString, char_t** ppStringEnd);</font></td>
    </tr>
    <tr> 
        <td>Memset16</td>
        <td>Sets 16 bit values in memory (as opposed to memset's 8 bit values)</td>
        <td><font size="-1">uint16_t* Memset16(void* pDestination, uint16_t c, size_t count); </font></td>
    </tr>
    <tr> 
        <td>Memset32</td>
        <td>Sets 32 bit values in memory (as opposed to memset's 8 bit values)</td>
        <td><font size="-1"> uint32_t* Memset32(void* pDestination, uint32_t c, size_t count);</font></td>
    </tr>
    <tr> 
        <td>Memset64</td>
        <td>Sets 64 bit values in memory (as opposed to memset's 8 bit values)</td>
        <td><font size="-1">uint64_t* Memset64(void* pDestination, uint64_t c, size_t count);</font></td>
    </tr>
    <tr> 
        <td>MemsetN</td>
        <td>Sets arbitrarily sized values in memory.</td>
        <td><font size="-1">void* MemsetN (void* pDestination, const void* pSource, size_t sourceBytes, size_t count); </font></td>
    </tr>
    <tr> 
        <td>EcvtBuf</td>
        <td>Base function for converting a float to a %e string.</td>
        <td> 
            <p><font size="-1">char_t* EcvtBuf(double dValue, int nDigitCount, int* decimalPos, int* sign, char_t* buffer); </font></p>
        </td>
    </tr>
    <tr> 
        <td>FcvtBuf</td>
        <td>Base function for converting a float to a %f string.</td>
        <td><font size="-1">char_t* FcvtBuf(double dValue, int nDigitCountAfterDecimal, int* decimalPos, int* sign, char_t* buffer); </font></td>
    </tr>
</table>
<h2>Example usage </h2>
<p>We provide a random smattering of example code here.</p>
<pre class="code-example">char16_t buffer[32] = L"hello ";

Strcat(buffer, L"world");
</pre>
<p>Strlcpy, Strlcat:</p>

<pre class="code-example">char8_t buffer[32];


Strlcpy(buffer, "Hello ", sizeof(buffer));<br>Strlcat(buffer, "world", sizeof(buffer));
</pre>
<p>Strlcpy, used to translate UTF8 to UTF16: </p>
<pre class="code-example">char8_t  buffer8[64];
char16_t buffer16[64];


int length16 = Strlcpy(buffer16, buffer8, 64);</pre>
<p>U64toa:</p>
<pre class="code-example">char buffer[32];
U64toa(UINT64_C(12345678901234567890), buffer, 16);
</pre>
<p>AtoI32:</p>

<pre class="code-example">int32_t x = AtoI32(&quot;1234567890&quot;);
</pre>
<p>Strtod:</p>
<pre class="code-example">const char16_t* pString = L"12345.678 123.456 1.23456";

while(*pString)
{
    double value = Strtod(pString, &pString);
    printf("Field = %f\n, value);
}
</pre>
<h2>Interface</h2>
<p>In each of the functions below, there is an char8_t and char16_t version. So for Strcat there are the following:</p>
<blockquote>
  <p><span class="code-example-span">char8_t*       &nbsp;Strcat(char8_t* &nbsp;pDestination, const char8_t* &nbsp;pSource)<br>
  </span><span class="code-example-span">char16_t* Strcat(char16_t* pDestination, const char16_t* pSource)</span></p>
</blockquote>
<p>The list below may be out of date as you read this, so see EAString.h for a definitive list of supported functionality.</p>
<pre class="code-example">char_t*       Strcat(char_t* pDestination, const char_t* pSource);
char_t*       Strncat(char_t* pDestination, const char_t* pSource, size_t n);
char_t*       Strlcat(char_t* pDestination, const char_t* pSource, size_t n);
char_t*       Strcpy(char_t* pDestination, const char_t* pSource);
char_t*       Strncpy(char_t* pDestination, const char_t* pSource, size_t n);
char_t*       Strlcpy(char_t* pDestination, const char_t* pSource, size_t n);
int           Strlcpy(char16_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char32_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char8_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char32_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char8_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char16_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char8_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char16_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(char32_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(wchar_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(wchar_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
int           Strlcpy(wchar_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength = (size_t)~0);
bool          Strlcpy(char16_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char32_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char8_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char32_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char8_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char16_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed); 
bool          Strlcpy(char8_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char16_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(char32_t* pDestination, const wchar_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed); 
bool          Strlcpy(wchar_t* pDestination, const char8_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(wchar_t* pDestination, const char16_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed);
bool          Strlcpy(wchar_t* pDestination, const char32_t* pSource, size_t nDestCapacity, size_t nSourceLength, size_t&amp; nDestUsed, size_t&amp; nSourceUsed); 
size_t        Strlen(const char_t* pString);
size_t        Strxfrm(char_t* pDest, const char_t* pSource, size_t n);
char_t*       Strdup(const char_t* pString);
char_t*       Strlwr(char_t* pString);
char_t*       Strupr(char_t* pString);
char_t*       Strchr(const char_t* pString, char_t c);
size_t        Strcspn(const char_t* pString1, const char_t* pString2);
char_t*       Strpbrk(const char_t* pString1, const char_t* pString2);
char_t*       Strrchr(const char_t* pString, char_t c);
size_t        Strspn(const char_t* pString, const char_t* pSubString);
char_t*       Strstr(const char_t* pString, const char_t* pSubString);
char_t*       Stristr(const char_t* pString, const char_t* pSubString);
char_t*       Strtok(char_t* pString, const char_t*  pTokens, char_t** pContext);
char_t*       Strset(char_t* pString, char_t c);
char_t*       Strnset(char_t* pString, char_t c, size_t n);
char_t*       Strrev(char_t* pString);
int           Strcmp(const char_t* pString1, const char_t* pString2);
int           Strncmp(const char_t* pString1, const char_t* pString2, size_t n);
int           Stricmp(const char_t*  pString1, const char_t* pString2);
int           Strnicmp(const char_t* pString1, const char_t* pString2, size_t n);
int           Strcoll(const char_t*  pString1, const char_t* pString2);
int           Strncoll(const char_t* pString1, const char_t* pString2, size_t n);
int           Stricoll(const char_t* pString1, const char_t* pString2);
int           Strnicoll(const char_t* pString1, const char_t* pString1, size_t n);

char_t*       EcvtBuf(double dValue, int nDigitCount, int* decimalPos, int* sign, char_t* buffer);
char_t*       FcvtBuf(double dValue, int nDigitCountAfterDecimal, int* decimalPos, int* sign, char_t* buffer);

char_t*       I32toa(int32_t nValue, char_t* pResult, int nBase);
char_t*       U32toa(uint32_t nValue, char_t* pResult, int nBase);
char_t*       I64toa(int64_t nValue, char_t* pBuffer, int nBase);
char_t*       U64toa(uint64_t nValue, char_t* pBuffer, int nBase);
double        Strtod(const char_t* pString, char_t** ppStringEnd);
double        StrtodEnglish(const char_t* pString, char_t** ppStringEnd);
int64_t       StrtoI64(const char_t* pString, char_t** ppStringEnd, int nBase);
uint64_t      StrtoU64(const char_t* pString, char_t** ppStringEnd, int nBase);
int32_t       StrtoI32(const char_t* pString, char_t** ppStringEnd, int nBase);
uint32_t      StrtoU32(const char_t* pString, char_t** ppStringEnd, int nBase);
int32_t       AtoI32(const char_t* pString);
uint32_t      AtoU32(const char_t* pString);
int64_t       AtoI64(const char_t* pString);
uint64_t      AtoU64(const char_t* pString);
double        Atof(const char_t* pString);
double        AtofEnglish(const char_t* pString);
char_t*       Ftoa(double dValue, char_t* pResult, int nInputLength, int nPrecision, bool bExponentEnabled);
char_t*       FtoaEnglish(double dValue, char_t* pResult, int nInputLength, int nPrecision, bool bExponentEnabled);
</pre>
<h2>Encoded Strlcpy Issue </h2>
<p>The Strlcpy function <span class="code-example-comment"> size_t Strlcpy(char16_t* pDestination, const char8_t*  pSource, size_t nDestCapacity, size_t nSourceLength)</span> converts UTF8 text (char8_t) to UCS2  (char16_t). It doesn't work if your pSource string isn't truly UTF8-encoded. Typically this would happen because the source string is using Windows code page 1252 or HTML's ISO 8859-1. All 8 bit strings in EAStdC are assumed to be UTF8 unless specifically documented otherwise. </p>
<p>Any 8 bit text that's not UTF8 has to be defined within the context of a code page; otherwise any chars above 127 have an arbitrary meaning, and may include multi-byte characters for some code pages. If you need to convert code page 1252 to UCS2, you need to implement a function which uses a  table that maps the high byte values into their proper Unicode values. It's not so simple to just cast the byte value to char16_t, as some of the code page 1252 characters don't map directly to their numerical values in Unicode, though ISO 8859-1 characters to completely map to their equivalent Unicode values. </p>
<p>The following is an implementation of Strcpy and Strlcpy for ISO 8859-1 char8_t text which isn't currently part of EAStdC: </p>
<p class="code-example">char16_t* StrcpyISO8859_1(char16_t* pDestination, const char8_t* pSource)<br>
{<br>
&nbsp;&nbsp;&nbsp;&nbsp;char16_t* pDestSaved = pDestination;<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;while(*pSource)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*(pDestination++) = (uint8_t)*pSource++;<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;*pDestination = 0;<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;return pDestSaved;<br>
}</p>
<p> </p>
<p class="code-example">size_t StrlcpyISO8859_1(char16_t* pDestination, const char8_t* pSource, size_t nDestCapacity)<br>
{<br>
&nbsp;&nbsp;&nbsp;&nbsp;const char8_t* s = pSource;<br>
&nbsp;&nbsp;&nbsp;&nbsp;size_t n = nDestCapacity;<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;if(n &amp;&amp; --n)<br>
&nbsp;&nbsp;&nbsp;&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;do{<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if((*pDestination++ = (uint8_t)*s++) == 0)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} while(--n);<br>
&nbsp;&nbsp;&nbsp;&nbsp;}<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;if(!n)<br>
&nbsp;&nbsp;&nbsp;&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(nDestCapacity)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*pDestination = 0;<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;while(*s)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;++s;<br>
&nbsp;&nbsp;&nbsp;&nbsp;}<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;return (s - pSource - 1);<br>
}</p>
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