+/* $Id$ */
+
+/* vsnprintf( char *, size_t, const char *, va_list ap )
+
+ This file is part of the Public Domain C Library (PDCLib).
+ Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdbool.h>
+
+#ifndef REGTEST
+#include <_PDCLIB_io.h>
+
+/* returns true if callback-based output succeeded; else false */
+static inline bool cbout(
+ struct _PDCLIB_status_t * status,
+ const char *buf,
+ size_t size )
+{
+ size_t rv = status->write( status->ctx, buf, size );
+ status->i += rv;
+ return rv == size;
+}
+
+int _vcbprintf(
+ void *p,
+ size_t ( *cb ) ( void *p, const char *buf, size_t size ),
+ const char *format,
+ va_list arg )
+{
+ struct _PDCLIB_status_t status;
+ status.base = 0;
+ status.flags = 0;
+ status.n = 0;
+ status.i = 0;
+ status.current = 0;
+ status.width = 0;
+ status.prec = 0;
+ status.ctx = p;
+ status.write = cb;
+ va_copy( status.arg, arg );
+
+ /* Alternate between outputing runs of verbatim text and conversions */
+ while ( *format != '\0' )
+ {
+ const char *mark = format;
+ while ( *format != '\0' && *format != '%')
+ {
+ format++;
+ }
+
+ if ( mark != format )
+ {
+ if ( !cbout(&status, mark, format - mark) )
+ return -1;
+ }
+
+ if ( *format == '%' ) {
+ int consumed = _PDCLIB_print( format, &status );
+ if ( consumed > 0 )
+ {
+ format += consumed;
+ }
+ else if ( consumed == 0 )
+ {
+ /* not a conversion specifier, print verbatim */
+ if ( !cbout(&status, format++, 1) )
+ return -1;
+ }
+ else
+ {
+ /* I/O callback error */
+ return -1;
+ }
+ }
+ }
+
+ va_end( status.arg );
+ return status.i;
+}
+
+#endif
+
+#ifdef TEST
+#define _PDCLIB_FILEID "stdio/_vcbprintf.c"
+#define _PDCLIB_STRINGIO
+#include <stdint.h>
+#include <stddef.h>
+#include <_PDCLIB_test.h>
+
+#ifndef REGTEST
+
+static size_t testcb( void *p, const char *buf, size_t size )
+{
+ char **destbuf = p;
+ memcpy(*destbuf, buf, size);
+ *destbuf += size;
+ return size;
+}
+
+static int testprintf( char * s, const char * format, ... )
+{
+ int i;
+ va_list arg;
+ va_start( arg, format );
+ i = _vcbprintf( &s, testcb, format, arg );
+ *s = 0;
+ va_end( arg );
+ return i;
+}
+
+#endif
+
+int main( void )
+{
+ char target[100];
+#ifndef REGTEST
+#include "printf_testcases.h"
+#endif
+ return TEST_RESULTS;
+}
+
+#endif
+
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