source: cpp/frams/util/sstring.cpp @ 793

// This file is a part of Framsticks SDK.  http://www.framsticks.com/
// Copyright (C) 1999-2015  Maciej Komosinski and Szymon Ulatowski.
// See LICENSE.txt for details.

#include "sstring.h"
#include <common/nonstd.h> //to be sure the vsnprintf-related stuff gets included

#ifdef SSTRING_SIMPLE

// simple sstring implementation using direct character arrays
// - duplicate = copy all characters
// - no mutex needed

#include "sstring-simple.cpp"

#else
///////////////////////////////////////////////////////////////////////////
// old sstring implementation using SBuf references
// - duplicate = copy buffer pointer
// - mutex required to be thread safe

#include <common/nonstd_stl.h>
#include "extvalue.h"
#include <assert.h>

#ifdef MULTITHREADED
#include <pthread.h>
static pthread_mutex_t sstring_ref_lock = PTHREAD_MUTEX_INITIALIZER;
#define REF_LOCK pthread_mutex_lock(&sstring_ref_lock);
#define REF_UNLOCK pthread_mutex_unlock(&sstring_ref_lock)
#else
#define REF_LOCK 
#define REF_UNLOCK 
#endif

static int guessMemSize(int request)
{
        return request + min(request / 2, 10000) + 8;
}

SBuf::SBuf()
{
        txt = (char*)"";
        size = used = 0;
        refcount = 1;
}

SBuf::SBuf(int initsize)
{
        size = guessMemSize(initsize);
        if (size > 0)   { txt = (char*)malloc(size + 1); txt[0] = 0; }
        else    txt = (char*)"";
        used = 0;
        refcount = 1;
}

SBuf::~SBuf()
{
        freeBuf();
}

void SBuf::initEmpty()
{
        txt = (char*)"";
        used = size = 0;
        refcount = 1;
}

void SBuf::freeBuf()
{
        if (!size) return;
        free(txt); used = 0;
}

void SBuf::copyFrom(const char *ch, int chlen)
{
        if (chlen == -1) chlen = strlen(ch);
        if (chlen > 0)
        {
                if (chlen < size)
                {
                        memmove(txt, ch, chlen);
                }
                else
                {
                        size = guessMemSize(chlen);
                        char *newtxt = (char*)malloc(size + 1);
                        memcpy(newtxt, ch, chlen);
                        free(txt);
                        txt = newtxt;
                }
        }
        txt[chlen] = 0;
        used = chlen;
}

void SBuf::append(const char *ch, int chlen)
{ // doesn't check anything!
        memmove(txt + used, ch, chlen);
        used += chlen;
        txt[used] = 0;
}

void SBuf::ensureSize(int needed)
{
        if (size >= needed) return;
        needed = guessMemSize(needed);
        txt = (char*)realloc(txt, needed + 1);
        size = needed;
}

/////////////////////////////////////////////

SString::SString()
{
        initEmpty();
}

SString::~SString()
{
        REF_LOCK;
        detach();
        REF_UNLOCK;
}

SString::SString(int x)
{
        buf = new SBuf(x);
}

SString::SString(const char *t, int t_len)
{
        initEmpty();
        if (!t) return;
        copyFrom(t, t_len);
}

SString::SString(SString&& from)
{
        buf = from.buf;
        from.buf = &SBuf::empty();
}

SString::SString(const SString &from)
{
        if (from.buf == &SBuf::empty())
                buf = &SBuf::empty();
        else
        {
                REF_LOCK;
                buf = from.buf;
                if (buf->size)
                        buf->refcount++;
                REF_UNLOCK;
        }
}

void SString::initEmpty()
{
        buf = &SBuf::empty();
}

void SString::memoryHint(int howbig)
{
        detachCopy(howbig);
}

void SString::detachEmpty(int ensuresize)
{
        if (buf == &SBuf::empty()) { buf = new SBuf(ensuresize); return; }
        if (buf->refcount < 2) buf->ensureSize(ensuresize);
        else
        {
                buf->refcount--;
                buf = new SBuf(ensuresize);
        }
}

void SString::detach()
{
        if (buf == &SBuf::empty()) return;
        if (!--buf->refcount) delete buf;
}

void SString::detachCopy(int ensuresize)
{
        if (buf == &SBuf::empty()) { buf = new SBuf(ensuresize); return; }
        if (buf->refcount < 2)
        {
                buf->ensureSize(ensuresize);
                return;
        }
        buf->refcount--;
        SBuf *newbuf = new SBuf(ensuresize);
        newbuf->copyFrom(buf->txt, min(ensuresize, buf->used));
        buf = newbuf;
}

char *SString::directWrite(int ensuresize)
{
        if (ensuresize < 0) ensuresize = len();
        REF_LOCK;
        detachCopy(ensuresize);
        REF_UNLOCK;
        appending = buf->used;
        return buf->txt;
}

/*
char *SString::directWrite()
{
return directWrite(buf->used);
}
*/
char *SString::directAppend(int maxappend)
{
        REF_LOCK;
        detachCopy(buf->used + maxappend);
        REF_UNLOCK;
        appending = buf->used;
        return buf->txt + appending;
}

void SString::endWrite(int newlength)
{
        if (newlength < 0) newlength = strlen(buf->txt);
        else buf->txt[newlength] = 0;
        buf->used = newlength;
}

void SString::endAppend(int newappend)
{
        if (newappend < 0) newappend = strlen(buf->txt + appending);
        else buf->txt[appending + newappend] = 0;
        buf->used = appending + newappend;
}

////////////// append /////////////////

void SString::operator+=(const char *s)
{
        if (!s) return;
        int x = strlen(s);
        if (!x) return;
        append(s, x);
}

void SString::append(const char *txt, int count)
{
        if (!count) return;
        REF_LOCK;
        detachCopy(buf->used + count);
        REF_UNLOCK;
        buf->append(txt, count);
}

void SString::operator+=(const SString&s)
{
        append(s.c_str(), s.len());
}

SString SString::operator+(const SString& s) const
{
        SString ret(*this);
        ret += s;
        return ret;
}

/////////////////////////////

void SString::copyFrom(const char *ch, int chlen)
{
        if (!ch) chlen = 0;
        else if (chlen < 0) chlen = strlen(ch);
        REF_LOCK;
        detachEmpty(chlen);
        REF_UNLOCK;
        memmove(buf->txt, ch, chlen);
        buf->txt[chlen] = 0; buf->used = chlen;
}

void SString::operator=(const char *ch)
{
        copyFrom(ch);
}

void SString::operator=(const SString&s)
{
        if (s.buf == buf) return;
        REF_LOCK;
        detach();
        buf = s.buf;
        if (buf->size) buf->refcount++;
        REF_UNLOCK;
}
///////////////////////////////////////

SString SString::substr(int begin, int length) const
{
        if (begin < 0) { length += begin; begin = 0; }
        if (length >= (len() - begin)) length = len() - begin;
        if (length <= 0) return SString();
        if (length == len()) return *this;
        return SString((*this)(begin), length);
}

///////////////////////////////////////

bool SString::equals(const SString& s) const
{
        if (s.buf == buf) return true;
        return strcmp(buf->txt, s.buf->txt) == 0;
}

///////////////////////////////////////

int SString::indexOf(int character, int start) const
{
        const char *found = strchr(buf->txt + start, character);
        return found ? found - buf->txt : -1;
}

int SString::indexOf(const char *substring, int start) const
{
        char *found = strstr(buf->txt + start, substring);
        return found ? found - buf->txt : -1;
}

int SString::indexOf(const SString & substring, int start) const
{
        char *found = strstr(buf->txt + start, substring.c_str());
        return found ? found - buf->txt : -1;
}

bool SString::getNextToken(int& pos, SString &token, char separator) const
{
        if (pos >= len()) { token = 0; return false; }
        int p1 = pos, p2;
        const char *t1 = buf->txt + pos;
        const char *t2 = strchr(t1, separator);
        if (t2) pos = (p2 = (t2 - buf->txt)) + 1; else p2 = pos = len();
        strncpy(token.directWrite(p2 - p1), t1, p2 - p1);
        token.endWrite(p2 - p1);
        return true;
}

bool SString::startsWith(const char *pattern) const
{
        const char *t = this->c_str();
        for (; *pattern; pattern++, t++)
                if (*t != *pattern) return false;
        return true;
}

SString SString::valueOf(int i)
{
        return SString::sprintf("%d", i);
}
SString SString::valueOf(long i)
{
        return SString::sprintf("%d", i);
}
SString SString::valueOf(double d)
{
        SString tmp = SString::sprintf("%.15g", d);
        if ((!strchr(tmp.c_str(), '.')) && (!strchr(tmp.c_str(), 'e'))) tmp += ".0";
        return tmp;
}
SString SString::valueOf(const SString& s)
{
        return s;
}

#if 0 //testing _vscprintf
#define USE_VSCPRINTF
int _vscprintf(const char *format, va_list argptr)
{
        return vsnprintf("", 0, format, argptr);
}
#endif

SString SString::sprintf(const char* format, ...)
{
        int n, size = 30;
        va_list ap;

        SString ret;

#ifdef USE_VSCPRINTF
        va_start(ap, format);
        size = _vscprintf(format, ap);
        va_end(ap);
#endif

        while (1)
        {
                char* p = ret.directWrite(size);
                assert(p != NULL);
                size = ret.directMaxLen() + 1;
                /* Try to print in the allocated space. */
                va_start(ap, format);
                n = vsnprintf(p, size, format, ap);
                va_end(ap);
                /* If that worked, return the string. */
                if (n > -1 && n < size)
                {
                        ret.endWrite(n);
                        return ret;
                }
                /* Else try again with more space. */
#ifdef VSNPRINTF_RETURNS_REQUIRED_SIZE
                if (n > -1)    /* glibc 2.1 */
                        size = n; /* precisely what is needed */
                else           /* glibc 2.0 */
#endif
                        size *= 2;  /* twice the old size */
        }
}

SString &SString::empty()
{
        static SString empty;
        return empty;
}

SBuf &SBuf::empty()
{
        static SBuf empty;
        return empty;
}

#endif //#ifdef SSTRING_SIMPLE

//////////////////////////////////////////////////
// to be moved somewhere else?
// public domain source: http://isthe.com/chongo/src/fnv
typedef uint32_t Fnv32_t;

#define FNV_32_PRIME ((Fnv32_t)0x01000193)
#define FNV1_32_INIT ((Fnv32_t)0x811c9dc5)
#define FNV1_32A_INIT FNV1_32_INIT

Fnv32_t fnv_32a_buf(void *buf, size_t len, Fnv32_t hval)
{
        unsigned char *bp = (unsigned char *)buf;       /* start of buffer */
        unsigned char *be = bp + len;           /* beyond end of buffer */

        while (bp < be) {

                /* xor the bottom with the current octet */
                hval ^= (Fnv32_t)*bp++;

                /* multiply by the 32 bit FNV magic prime mod 2^32 */
#if defined(NO_FNV_GCC_OPTIMIZATION)
                hval *= FNV_32_PRIME;
#else
                hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
#endif

        }

        /* return our new hash value */
        return hval;
}
//////////////////////////////////////////////////

#ifdef SSTRING_SIMPLE
uint32_t SString::hash() const
{
        return fnv_32a_buf(txt, used, FNV1_32A_INIT);
}
#else
uint32_t SBuf::hash() const
{
        return fnv_32a_buf(txt, used, FNV1_32A_INIT);
}
#endif