Add _cbprintf/_vcbprintf (callback based printf formatters)

[pdclib.old] / functions / stdio / _vcbprintf.c

diff --git a/functions/stdio/_vcbprintf.c b/functions/stdio/_vcbprintf.c
new file mode 100644 (file)
index 0000000..dbb2171
--- /dev/null
+++ b/functions/stdio/_vcbprintf.c
@@ -0,0 +1,126 @@
+/* $Id$ */
+
+/* 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
+