Add basic piped input support

README.md

@@ -14,8 +14,14 @@ OR
 
 ## runtime configuration
 This is done by setting environment variables.
-- `RBTEXT_FULLSCREEN` (default: Enabled) - Clear screen every print (useful for text that will wrap)
+- `RBTEXT_FULLSCREEN` (default: Enabled, force disable when non-tty) - Clear screen every print (useful for text that will wrap)
 
 ### example
-Runs rbtext without clearing the screen everytime
+Runs rbtext without clearing the screen everytime <br/>
 `RBTEXT_FULLSCREEN=-1 ./rbtext hello world`
+<hr/>
+Runs rbtext with piped input <br/>
+`echo "hello world" | ./rbtext`
+
+## note on piped input
+Piping input will cause rbtext to stop refreshing the screen. This is because it expects constant output, like in the following command: `cat /dev/urandom | base -w 0 | ./rbtext`

in

@@ -0,0 +1 @@
+text

rbtext.c

@@ -16,7 +16,7 @@ this program. If not, see <https://www.gnu.org/licenses/>.
 
 */
 
-#include <memory.h>
+//#include <memory.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -31,7 +31,7 @@ this program. If not, see <https://www.gnu.org/licenses/>.
 #define CONF_SLEEP_TIMESEC (time_t)0
 // How many times a color should be shown before switching to the next ( DEFAULT
 // = 2 )
-#define CONF_COLOR_LAG 2
+#define CONF_COLOR_LAG 3
 
 // Don't set to 0
 // Disabled = -1
@@ -53,15 +53,33 @@ const char *COLORS[] = {
     "193;71;153", // PINK
 };
 
+// Used for detecting pipe, don't change!
+uint use_pipe = 0;
+
 unsigned long COLORS_SIZE = sizeof(COLORS) / sizeof(char *);
 unsigned long long t = 0;
 void genColors(char *s) {
   char *cstr = (char *)malloc(64 + 1);
 
-  for (unsigned long i = 0; i < strlen(s); i++) {
-    unsigned long c = ((t + i) / CONF_COLOR_LAG) % COLORS_SIZE;
-    snprintf(cstr, 64, "\e[38;2;%sm", COLORS[c]);
-    printf("%s%c\e[0m", cstr, s[i]);
+  if (use_pipe) {
+    char *buffer = (char *)malloc(1024 + 1);
+    long r = read(STDIN_FILENO, buffer, 1024);
+
+    if (r < 1) return;
+
+    for (unsigned long i = 0; i < r; i++) {
+      unsigned long c = ((t + 1) / CONF_COLOR_LAG) % COLORS_SIZE;
+      snprintf(cstr, 64, "\e[38;2;%sm", COLORS[c]);
+      printf("%s%c\e[0m", cstr, buffer[i]);
+    }
+
+    free(buffer);
+  } else {
+    for (unsigned long i = 0; i < strlen(s); i++) {
+      unsigned long c = ((t + i) / CONF_COLOR_LAG) % COLORS_SIZE;
+      snprintf(cstr, 64, "\e[38;2;%sm", COLORS[c]);
+      printf("%s%c\e[0m", cstr, s[i]);
+    }
   }
 
   free(cstr);
@@ -79,42 +97,51 @@ void set_flag(int *flag, const char *env) {
 }
 
 int main(int argc, char **argv) {
-  if (argc < 2) {
+  if (!isatty(STDIN_FILENO)) {
+    use_pipe = 1;
+  } else if (argc < 2) {
     // [ERROR] No arguments given. USAGE: ... <text>
     printf("\e[1;31m[ERROR]\e[0m No arguments given.\n\tUSAGE: \e[34m%s "
-           "\e[33m<text>\e[0m\n",
+           "\e[33m[<text>...]\e[0m\n",
            argv[0]);
     return 1;
   }
 
   set_flag(&FLAG_FULLSCREEN, "RBTEXT_FULLSCREEN");
 
-  uint reqSize = 0;
-  for (int i = 1; i < argc; i++) {
-    reqSize += strlen(argv[i]);
-  }
+  char *text;
+  if (!use_pipe) {
+    uint reqSize = 0;
+    for (int i = 1; i < argc; i++) {
+      reqSize += strlen(argv[i]);
+    }
 
-  char *text = (char *)malloc(reqSize + argc);
+    text = (char *)malloc(reqSize + argc);
 
-  // Adds all the arguments together with spaces seperating them
-  for (int i = 1, j = 0; i < argc; i++) {
-    for (unsigned int k = 0; k < strlen(argv[i]); k++, j++)
-      text[j] = argv[i][k];
+    // Adds all the arguments together with spaces seperating them
+    for (int i = 1, j = 0; i < argc; i++) {
+      for (unsigned int k = 0; k < strlen(argv[i]); k++, j++)
+        text[j] = argv[i][k];
 
-    text[j] = ' ';
-    j++;
+      text[j] = ' ';
+      j++;
+    }
   }
 
   struct timespec rem,
       req = {CONF_SLEEP_TIMESEC, CONF_SLEEP_TIMEMS * 1000 * 1000};
 
   while (1) {
-    if (FLAG_FULLSCREEN == 1)
-      printf("\e[2J\e[f");
-    else
-      printf("\r");
+    if (!use_pipe) {
+      if (FLAG_FULLSCREEN == 1)
+        printf("\e[2J\e[f");
+      else
+        printf("\r");
+    }
+
     genColors(text);
     fflush(stdout);
+
     nanosleep(&req, &rem);
     t += 1;
   }