stringbuffer.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2002 Thamer Alharbash
 * Copyright 2009 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 **********************************************************************/



#include "liblwgeom_internal.h"
#include "stringbuffer.h"

stringbuffer_t*
stringbuffer_create(void)
{
        return stringbuffer_create_with_size(STRINGBUFFER_STARTSIZE);
}

static void
stringbuffer_init_with_size(stringbuffer_t *s, size_t size)
{
        s->str_start = lwalloc(size);
        s->str_end = s->str_start;
        s->capacity = size;
        memset(s->str_start, 0, size);
}

void
stringbuffer_release(stringbuffer_t *s)
{
        if ( s->str_start ) lwfree(s->str_start);
}

void
stringbuffer_init(stringbuffer_t *s)
{
        stringbuffer_init_with_size(s, STRINGBUFFER_STARTSIZE);
}

stringbuffer_t*
stringbuffer_create_with_size(size_t size)
{
        stringbuffer_t *s;

        s = lwalloc(sizeof(stringbuffer_t));
        stringbuffer_init_with_size(s, size);
        return s;
}

void
stringbuffer_destroy(stringbuffer_t *s)
{
        stringbuffer_release(s);
        if ( s ) lwfree(s);
}

void
stringbuffer_clear(stringbuffer_t *s)
{
        s->str_start[0] = '\0';
        s->str_end = s->str_start;
}

static inline void
stringbuffer_makeroom(stringbuffer_t *s, size_t size_to_add)
{
        size_t current_size = (s->str_end - s->str_start);
        size_t capacity = s->capacity;
        size_t required_size = current_size + size_to_add;

        while (capacity < required_size)
                capacity *= 2;

        if ( capacity > s->capacity )
        {
                s->str_start = lwrealloc(s->str_start, capacity);
                s->capacity = capacity;
                s->str_end = s->str_start + current_size;
        }
}

char
stringbuffer_lastchar(stringbuffer_t *s)
{
        if( s->str_end == s->str_start )
                return 0;

        return *(s->str_end - 1);
}

void
stringbuffer_append(stringbuffer_t *s, const char *a)
{
        int alen = strlen(a); /* Length of string to append */
        int alen0 = alen + 1; /* Length including null terminator */
        stringbuffer_makeroom(s, alen0);
        memcpy(s->str_end, a, alen0);
        s->str_end += alen;
}

const char*
stringbuffer_getstring(stringbuffer_t *s)
{
        return s->str_start;
}

char*
stringbuffer_getstringcopy(stringbuffer_t *s)
{
        size_t size = (s->str_end - s->str_start) + 1;
        char *str = lwalloc(size);
        memcpy(str, s->str_start, size);
        str[size - 1] = '\0';
        return str;
}

int
stringbuffer_getlength(stringbuffer_t *s)
{
        return (s->str_end - s->str_start);
}

void
stringbuffer_set(stringbuffer_t *s, const char *str)
{
        stringbuffer_clear(s);
        stringbuffer_append(s, str);
}

void
stringbuffer_copy(stringbuffer_t *dst, stringbuffer_t *src)
{
        stringbuffer_set(dst, stringbuffer_getstring(src));
}

static int
stringbuffer_avprintf(stringbuffer_t *s, const char *fmt, va_list ap)
{
        int maxlen = (s->capacity - (s->str_end - s->str_start));
        int len = 0; /* Length of the output */
        va_list ap2;

        /* Make a copy of the variadic arguments, in case we need to print twice */
        /* Print to our buffer */
        va_copy(ap2, ap);
        len = vsnprintf(s->str_end, maxlen, fmt, ap2);
        va_end(ap2);

        /* Propogate errors up */
        if ( len < 0 )
                #if defined(__MINGW64_VERSION_MAJOR)
                len = _vscprintf(fmt, ap2);
                #else
                return len;
                #endif

        /* We didn't have enough space! */
        /* Either Unix vsnprint returned write length larger than our buffer */
        /*     or Windows vsnprintf returned an error code. */
        if ( len >= maxlen )
        {
                stringbuffer_makeroom(s, len + 1);
                maxlen = (s->capacity - (s->str_end - s->str_start));

                /* Try to print a second time */
                len = vsnprintf(s->str_end, maxlen, fmt, ap);

                /* Printing error? Error! */
                if ( len < 0 ) return len;
                /* Too long still? Error! */
                if ( len >= maxlen ) return -1;
        }

        /* Move end pointer forward and return. */
        s->str_end += len;
        return len;
}

int
stringbuffer_aprintf(stringbuffer_t *s, const char *fmt, ...)
{
        int r;
        va_list ap;
        va_start(ap, fmt);
        r = stringbuffer_avprintf(s, fmt, ap);
        va_end(ap);
        return r;
}

int
stringbuffer_trim_trailing_white(stringbuffer_t *s)
{
        char *ptr = s->str_end;
        int dist = 0;

        /* Roll backwards until we hit a non-space. */
        while( ptr > s->str_start )
        {
                ptr--;
                if( (*ptr == ' ') || (*ptr == '\t') )
                {
                        continue;
                }
                else
                {
                        ptr++;
                        dist = s->str_end - ptr;
                        *ptr = '\0';
                        s->str_end = ptr;
                        return dist;
                }
        }
        return dist;
}

int
stringbuffer_trim_trailing_zeroes(stringbuffer_t *s)
{
        char *ptr = s->str_end;
        char *decimal_ptr = NULL;
        int dist;

        if ( s->str_end - s->str_start < 2)
                return 0;

        /* Roll backwards to find the decimal for this number */
        while( ptr > s->str_start )
        {
                ptr--;
                if ( *ptr == '.' )
                {
                        decimal_ptr = ptr;
                        break;
                }
                if ( (*ptr >= '0') && (*ptr <= '9' ) )
                        continue;
                else
                        break;
        }

        /* No decimal? Nothing to trim! */
        if ( ! decimal_ptr )
                return 0;

        ptr = s->str_end;

        /* Roll backwards again, with the decimal as stop point, trimming contiguous zeroes */
        while( ptr >= decimal_ptr )
        {
                ptr--;
                if ( *ptr == '0' )
                        continue;
                else
                        break;
        }

        /* Huh, we get anywhere. Must not have trimmed anything. */
        if ( ptr == s->str_end )
                return 0;

        /* If we stopped at the decimal, we want to null that out.
           It we stopped on a numeral, we want to preserve that, so push the
           pointer forward one space. */
        if ( *ptr != '.' )
                ptr++;

        /* Add null terminator re-set the end of the stringbuffer. */
        *ptr = '\0';
        dist = s->str_end - ptr;
        s->str_end = ptr;
        return dist;
}