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/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2007, University of Amsterdam
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <SWI-Stream.h>
#include <SWI-Prolog.h>
#include <string.h>
#define TRYPUTC(c, s) if ( Sputcode(c, s) < 0 ) { return -1; }
static int
json_put_code(IOSTREAM *out, int pc, int c)
{ static char escape[128];
static int escape_initialized = FALSE;
if ( !escape_initialized )
{ memset(escape, 0, sizeof(escape));
escape['"'] = '"';
escape['\\'] = '\\';
escape['\b'] = 'b';
escape['\f'] = 'f';
escape['\n'] = 'n';
escape['\r'] = 'r';
escape['\t'] = 't';
escape_initialized = TRUE;
}
if ( c < 128 )
{ if ( escape[c] )
{ TRYPUTC('\\', out);
TRYPUTC(escape[c], out);
} else if ( c < ' ' ) /* control characters *must* be escaped */
{ TRYPUTC('\\', out);
if ( Sfprintf(out, "u%04x", c) < 0 )
return -1;
} else if ( pc == '<' && c == '/' ) /* Emit </ inside a string as <\/ to */
/* allow safe embedding in html */
{ TRYPUTC('\\', out);
TRYPUTC('/', out);
} else
{ TRYPUTC(c, out);
}
} else
{ TRYPUTC(c, out);
}
return 0;
}
#undef TRYPUTC
#define TRYPUTC(c, s) if ( Sputcode(c, s) < 0 ) { rc = FALSE; goto out; }
static foreign_t
json_write_string(term_t stream, term_t text)
{ IOSTREAM *out;
char *a;
pl_wchar_t *w;
size_t len;
int rc = TRUE;
if ( !PL_get_stream_handle(stream, &out) )
return FALSE;
if ( PL_get_nchars(text, &len, &a, CVT_ATOM|CVT_STRING|CVT_LIST) )
{ const char *ap;
size_t todo;
int pc = 0;
TRYPUTC('"', out);
for(todo=len, ap=a; todo-- > 0; ap++)
{ int c = *ap&0xff;
if ( json_put_code(out, pc, c) < 0 )
{ rc = FALSE; goto out;
}
pc = c;
}
TRYPUTC('"', out);
} else if ( PL_get_wchars(text, &len, &w, CVT_ATOM|CVT_STRING|CVT_LIST|CVT_EXCEPTION) )
{ const pl_wchar_t *wp;
size_t todo;
int pc = 0;
TRYPUTC('"', out);
for(todo=len, wp=w; todo-- > 0; wp++)
{ int c = *wp;
if ( json_put_code(out, pc, c) < 0 )
{ rc = FALSE; goto out;
}
pc = c;
}
TRYPUTC('"', out);
} else
{ rc = FALSE;
}
out:
PL_release_stream(out);
return rc;
}
static foreign_t
json_write_indent(term_t stream, term_t indent, term_t tab)
{ int i, t, n;
IOSTREAM *out;
if ( !PL_get_integer(indent, &i) ||
!PL_get_integer(tab, &t) )
return FALSE;
if ( PL_get_stream_handle(stream, &out) )
{ int rc = TRUE;
if ( !out->position || out->position->linepos > 0 )
{ TRYPUTC('\n', out);
}
for(n=0; n<i/t; n++)
TRYPUTC('\t', out);
for(n=0; n<i%t; n++)
TRYPUTC(' ', out);
out:
PL_release_stream(out);
return rc;
}
return FALSE;
}
install_t
install_json()
{ PL_register_foreign("json_write_string", 2, json_write_string, 0);
PL_register_foreign("json_write_indent", 3, json_write_indent, 0);
}
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