Connect fprintf family to putc

mos-platform/common/c/printf.cc

@@ -19,10 +19,10 @@ namespace {
 
 void put(char c, Status *status) {
   if (status->i < status->n) {
-    if (status->s)
-      status->s[status->i] = c;
+    if (status->stream)
+      putc(c, status->stream);
     else
-      putchar(c);
+      status->s[status->i] = c;
   }
   ++status->i;
 }
@@ -883,6 +883,7 @@ __attribute__((weak)) int vfprintf(FILE *__restrict__ stream,
   status.n = SIZE_MAX;
   status.i = 0;
   status.s = NULL;
+  status.stream = stream;
 
   va_copy(status.arg, arg);
 
@@ -891,8 +892,8 @@ __attribute__((weak)) int vfprintf(FILE *__restrict__ stream,
 
     if ((*format != '%') || ((rc = print(format, &status)) == format)) {
       /* No conversion specifier, print verbatim */
-      putchar(*format);
-      ++format;
+      if (putc(*format++, stream) == EOF)
+        return EOF;
       status.i++;
     } else {
       /* Continue parsing after conversion specifier */
@@ -917,6 +918,7 @@ __attribute__((weak)) int vsnprintf(char *__restrict__ s, size_t n,
   status.n = n;
   status.i = 0;
   status.s = s;
+  status.stream = NULL;
 
   va_copy(status.arg, arg);
 

mos-platform/common/c/stdio-full.c

@@ -52,9 +52,26 @@ struct _FILE {
   FILE *next;           // Pointer to next struct (internal)
 };
 
-static FILE serr = {.handle = 2, .status = _IONBF | FWRITE};
-static FILE sout = {.handle = 1, .status = _IONBF | FWRITE, .next = &serr};
-static FILE sin = {.handle = 0, .status = _IONBF | FREAD, .next = &sout};
+// Buffer one-two lines; write() implementations have constant overhead, and
+// buffering amortizes it.
+static char serr_buf[80];
+static char sout_buf[80];
+static char sin_buf[80];
+
+static FILE serr = {.handle = 2,
+                    .buffer = serr_buf,
+                    .bufsize = sizeof(serr_buf),
+                    .status = _IONBF | FWRITE};
+static FILE sout = {.handle = 1,
+                    .buffer = sout_buf,
+                    .bufsize = sizeof(sout_buf),
+                    .status = _IONBF | FWRITE,
+                    .next = &serr};
+static FILE sin = {.handle = 0,
+                   .buffer = sin_buf,
+                   .bufsize = sizeof(sin_buf),
+                   .status = _IONBF | FREAD,
+                   .next = &sout};
 
 FILE *stdin = &sin;
 FILE *stdout = &sout;

mos-platform/common/c/util.h

@@ -11,6 +11,7 @@
 #include <stdarg.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <stdio.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -28,6 +29,7 @@ struct Status {
                     // *sscanf():  source string
   size_t width;     // specified field width
   int prec;         // specified field precision
+  FILE *stream;     // *fprintf() / *fscanf() stream
   va_list arg;      // argument stack
 };