printf: better support for escape sequences

Upstream printf outputs one character at a time which doesn't
play well with emulation of ANSI escape sequences.  Previous
workarounds for this only applied in limited circumstances.

Try a different approach:  replace putchar() and printf() calls
in the printf applet with custom routines which store the output
in memory.  It's only really output at the end of the program or
when a newline is detected and a non-trivial amount has been
collected.

1 files changed, 60 insertions, 48 deletions

diff --git a/coreutils/printf.c b/coreutils/printf.c
index 01f730073..7d36fdd61 100644
--- a/coreutils/printf.c
+++ b/coreutils/printf.c
@@ -152,22 +152,70 @@ static double my_xstrtod(const char *arg)
 }
 
 #if ENABLE_PLATFORM_MINGW32
-static size_t fwrite_stdout(const char *s, const char *t)
+static int buflen = 0;
+static int bufmax = 0;
+static char *buffer = NULL;
+
+static void my_flush(void)
+{
+        if (buffer)
+                full_write(STDOUT_FILENO, buffer, buflen);
+        free(buffer);
+        buffer = NULL;
+        buflen = bufmax = 0;
+}
+
+static int my_putchar(int ch)
 {
-        return fwrite(s, t - s, 1, stdout);
+        if (buflen + 1 >= bufmax) {
+                bufmax += 256;
+                buffer = xrealloc(buffer, bufmax);
+        }
+        buffer[buflen++] = ch;
+        if (buflen > 40 && ch == '\n')
+                my_flush();
+        return ch;
 }
+
+static int my_printf(const char *format, ...)
+{
+        va_list list;
+        char *str;
+        int len;
+
+        va_start(list, format);
+        len = vasprintf(&str, format, list);
+        va_end(list);
+
+        if (len < 0)
+                bb_die_memory_exhausted();
+
+        if (buflen + len >= bufmax) {
+                bufmax += 256 + len;
+                buffer = xrealloc(buffer, bufmax);
+        }
+        memcpy(buffer + buflen, str, len);
+        buflen += len;
+        free(str);
+
+        if (buflen > 40 && buffer[buflen-1] == '\n')
+                my_flush();
+
+        return len;
+}
+
+#undef bb_putchar
+#undef putchar
+#undef printf
+#define bb_putchar(c) my_putchar(c)
+#define putchar(c) my_putchar(c)
+#define printf(...) my_printf(__VA_ARGS__)
 #endif
 
 /* Handles %b; return 1 if output is to be short-circuited by \c */
 static int print_esc_string(const char *str)
 {
         char c;
-#if ENABLE_PLATFORM_MINGW32
-        char *s, *t;
-        int ret = 0;
-
-        s = t = xstrdup(str);
-#endif
         while ((c = *str) != '\0') {
                 str++;
                 if (c == '\\') {
@@ -179,12 +227,7 @@ static int print_esc_string(const char *str)
                                 }
                         }
                         else if (*str == 'c') {
-#if ENABLE_PLATFORM_MINGW32
-                                ret = 1;
-                                goto finish;
-#else
                                 return 1;
-#endif
                         }
                         {
                                 /* optimization: don't force arg to be on-stack,
@@ -194,20 +237,10 @@ static int print_esc_string(const char *str)
                                 str = z;
                         }
                 }
-#if ENABLE_PLATFORM_MINGW32
-                *t++ = c;
-#else
                 putchar(c);
-#endif
         }
-#if ENABLE_PLATFORM_MINGW32
- finish:
-        fwrite_stdout(s, t);
-        free(s);
-        return ret;
-#else
+
         return 0;
-#endif
 }
 
 static void print_direc(char *format, unsigned fmt_length,
@@ -321,18 +354,10 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
         int field_width;        /* Arg to first '*' */
         int precision;          /* Arg to second '*' */
         char **saved_argv = argv;
-#if ENABLE_PLATFORM_MINGW32
-        char *s, *t;
-        s = t = auto_string(xstrdup(f));
-#endif
 
         for (; *f; ++f) {
                 switch (*f) {
                 case '%':
-#if ENABLE_PLATFORM_MINGW32
-                        fwrite_stdout(s, t);
-                        t = s;
-#endif
                         direc_start = f++;
                         direc_length = 1;
                         field_width = precision = 0;
@@ -421,18 +446,6 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
                                 free(p);
                         }
                         break;
-#if ENABLE_PLATFORM_MINGW32
-                case '\\':
-                        if (*++f == 'c') {
-                                fwrite_stdout(s, t);
-                                return saved_argv; /* causes main() to exit */
-                        }
-                        *t++ = bb_process_escape_sequence((const char **)&f);
-                        f--;
-                        break;
-                default:
-                        *t++ = *f;
-#else
                 case '\\':
                         if (*++f == 'c') {
                                 return saved_argv; /* causes main() to exit */
@@ -442,12 +455,8 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
                         break;
                 default:
                         putchar(*f);
-#endif
                 }
         }
-#if ENABLE_PLATFORM_MINGW32
-        fwrite_stdout(s, t);
-#endif
 
         return argv;
 }
@@ -495,6 +504,9 @@ int printf_main(int argc UNUSED_PARAM, char **argv)
         do {
                 argv = argv2;
                 argv2 = print_formatted(format, argv, &conv_err);
+#if ENABLE_PLATFORM_MINGW32
+                my_flush();
+#endif
         } while (argv2 > argv && *argv2);
 
         /* coreutils compat (bash doesn't do this):