From 87d05f158cb6c552c1de528628bbf10c65e0edb6 Mon Sep 17 00:00:00 2001
From: Francois Fleuret <francois@fleuret.org>
Date: Mon, 29 Mar 2010 13:45:10 +0200
Subject: [PATCH] Major changes in the progress bad printing.

---
 finddup.c | 70 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 50 insertions(+), 20 deletions(-)

diff --git a/finddup.c b/finddup.c
index 197b82e..6b14142 100644
--- a/finddup.c
+++ b/finddup.c
@@ -47,6 +47,8 @@
 /* 1M really helps compared to 64k */
 #define READ_BUFFER_SIZE (1024 * 1024)
 
+#define PROGRESS_BUFFER_SIZE 1024
+
 typedef int64_t size_sum_t;
 
 /* Yeah, global variables! */
@@ -382,27 +384,44 @@ void print_result(struct file_node *list1, struct file_node *list2) {
   free(nodes);
 }
 
-void print_progress(int max, int n, int *pp) {
-  int p, k;
-  int width, tty_width;
+struct progress_state {
+  int bar_width;
+  int nb_values, value;
+  int last_position;
+};
+
+void print_progress(struct progress_state *state) {
+  int position, k;
   struct winsize win;
+  char buffer[PROGRESS_BUFFER_SIZE];
+  char *s;
 
-  if(show_progress &&
-     isatty(STDOUT_FILENO) &&
-     !ioctl (STDOUT_FILENO, TIOCGWINSZ, (char *) &win)) {
-    tty_width = win.ws_col;
-    width = tty_width - 7;
-    p = (width * n) / (max - 1);
-    if(p > *pp) {
-      for(k = 0; k < p; k++) {
-        fprintf(stderr, "+");
-      }
-      for(; k < width; k++) {
-        fprintf(stderr, "-");
+  if(show_progress) {
+    /* We use the previous bar_width to compute the position, so that
+       we avoid doing too many ioctls */
+    position = (state->bar_width * state->value) / (state->nb_values - 1);
+    if(state->bar_width <= 0 || position != state->last_position) {
+      if(!ioctl (STDERR_FILENO, TIOCGWINSZ, (char *) &win)) {
+        /* Something weird is going on if the previous test is wrong */
+        if(win.ws_col >= PROGRESS_BUFFER_SIZE) {
+          state->bar_width = PROGRESS_BUFFER_SIZE - 8;
+        } else {
+          state->bar_width = win.ws_col - 7;
+        }
+        position = (state->bar_width * state->value) / (state->nb_values - 1);
+        state->last_position = position;
+        s = buffer;
+        for(k = 0; k < position; k++) {
+          *(s++) = '+';
+        }
+        for(; k < state->bar_width; k++) {
+          *(s++) = '-';
+        }
+        sprintf(s, " [%3d%%]\r",
+                (100 * state->value) / (state->nb_values - 1));
+
+        fprintf(stderr, buffer);
       }
-      *pp = p;
-      p = (100 * n) / (max - 1);
-      fprintf(stderr, " [%3d%%]\r", p);
     }
   }
 }
@@ -410,6 +429,7 @@ void print_progress(int max, int n, int *pp) {
 void start(const char *dirname1, const char *dirname2) {
   struct file_node *list1, *list2;
   struct file_node *node1, *node2;
+  struct progress_state progress_state;
   int not_in, found;
   int nb_groups, nb_nodes;
   int list1_length, list2_length, previous_progress;
@@ -462,9 +482,14 @@ void start(const char *dirname1, const char *dirname2) {
   previous_progress = -1;
   nb_nodes = 0;
 
+  progress_state.bar_width = -1;
+  progress_state.last_position = -1;
+  progress_state.nb_values = list1_length;
+
   if(not_in) {
     for(node1 = list1; node1; node1 = node1->next) {
-      print_progress(list1_length, nb_nodes, &previous_progress);
+      progress_state.value = nb_nodes;
+      print_progress(&progress_state);
       nb_nodes++;
 
       found = 0;
@@ -486,7 +511,8 @@ void start(const char *dirname1, const char *dirname2) {
 
   } else {
     for(node1 = list1; node1; node1 = node1->next) {
-      print_progress(list1_length, nb_nodes, &previous_progress);
+      progress_state.value = nb_nodes;
+      print_progress(&progress_state);
       nb_nodes++;
 
       for(node2 = list2; node2; node2 = node2->next) {
@@ -626,6 +652,10 @@ int main(int argc, char **argv) {
     }
   }
 
+  if(!isatty(STDERR_FILENO)) {
+    show_progress = 0;
+  }
+
   if(optind + 2 == argc) {
     start(argv[optind], argv[optind + 1]);
   } else if(optind + 1 == argc) {
-- 
2.20.1