✨ Allow disk write speed limit to be specified as argument

src/errorAndExit.c

@@ -13,5 +13,6 @@ void errorAndExit() {
   fprintf(stderr, "  -k, --keys: Optionally, the three decryption keys used to decrypt the file before inflation.\n");
   fprintf(stderr, "  -p, --previous: Optionally, the location of the previous version of this file, in case this disk only contains the xdelta3 differences and not an actual file.\n");
   fprintf(stderr, "  -t, --target: The path where the extracted file is saved to. If not specified, the file is outputted to stdout.\n");
+  fprintf(stderr, "  -l, --limit: The maximum disk write speed in bytes per second, defaults to 30 MB/s if not specified.\n");
   exit(1);
 }

src/parseArguments.c

@@ -6,6 +6,7 @@
 #include "decrypt.h"
 #include "errorAndExit.h"
 #include "parseArguments.h"
+#include "rateLimiter.h"
 
 //Uses GNU's getopt_long_only(), see https://www.gnu.org/software/libc/manual/html_node/Getopt-Long-Options.html
 
@@ -17,6 +18,7 @@ static struct option long_options[] = {
   {"keys", required_argument, 0, 'k'},
   {"previous", required_argument, 0, 'p'},
   {"target", required_argument, 0, 't'},
+  {"limit", required_argument, 0, 'l'},
   {NULL, 0, 0, 0},
 };
 
@@ -82,6 +84,9 @@ struct arguments parseArguments(int argc, char *argv[]) {
       case 't': //target file path where extracted file is saved to
         state.target = optarg;
         break;
+      case 'l': //disk write limit
+        setDiskSpeed(atol(optarg));
+        break;
       case '?':
         errorAndExit();
         break;

src/rateLimiter.c

@@ -8,20 +8,25 @@
 #include "rateLimiter.h"
 #include "utils/min.h"
 
-//How many bytes we can write to disk per second: 30 MB/s. Use 0 to specify no limit
+//How many bytes we can write to disk per second. Use 0 to specify no limit. Default is 30 MB/s.
-#define DISK_SPEED 30UL * 1024UL * 1024UL
+unsigned long diskSpeed = 30UL * 1024UL * 1024UL;
 /** If we are not writing to disk, how many seconds the capacity can keep increasing before it reaches the limit.
  * Increasing this value can result in a spike of data once we are writing to disk again, but then allows the data
  * to quickly be written without having to wait for capacity to be available. */
 #define MAX_IDLE_TIME 3UL
 //Capacity can be filled up to this maximum amount
-#define CAPACITY_MAX DISK_SPEED * MAX_IDLE_TIME
+#define CAPACITY_MAX diskSpeed * MAX_IDLE_TIME
 
 //The current amount of free capacity
 unsigned long capacity = 0UL;
 
 time_t prevTime = 0;
 
+/** Set disk speed to the given speed in bytes per second. */
+void setDiskSpeed(unsigned long newSpeed) {
+  diskSpeed = newSpeed;
+}
+
 /** Increases the capacity based on time elapsed since the last time this function was called */
 void increaseCapacity() {
   //Get seconds since the last time this function was called, or default to 1 if this is the first time this function is called
@@ -34,7 +39,7 @@ void increaseCapacity() {
     timeElapsed = prevTime - prevTimeCache;
   }
 
-  capacity = min(CAPACITY_MAX, capacity + timeElapsed * DISK_SPEED);
+  capacity = min(CAPACITY_MAX, capacity + timeElapsed * diskSpeed);
 }
 
 /** Pauses execution until the given amount of capacity is available */

src/rateLimiter.h

@@ -1,4 +1,7 @@
 #pragma once
 
+/** Set disk speed to the given speed in bytes per second. */
+void setDiskSpeed(unsigned long newSpeed);
+
 /** Pauses execution until the given amount of capacity is available */
 void consumeCapacity(unsigned long numBytes);