initial second commit

src/main.c

@@ -7,67 +7,20 @@
 
 int main(void)
 {
-	int err;
-	bool detached = false;
-	libusb_device_handle *dev_handler;
 
-	/* Init BEGIN */
+	SETUP_PRINTER(PRINTER_VENDOR_ID, PRINTER_PRODUCT_ID);
+
+
+	printer_feed(0x10);
+
+	char* str = "This is a test string.";
+	
+	printer_print(str, strlen(str));
+
+	printer_feed(0x10);
+
+	printer_cut(false);
+
+	disconnect_from_printer();
 
-	err = libusb_init_context(NULL, NULL, 0);
-	if (err != 0) { 
-		perror("LIBUSB Error");
-		exit(-1);
-	}
-
-
-	dev_handler = libusb_open_device_with_vid_pid(NULL, 
-				PRINTER_VENDOR_ID, PRINTER_PRODUCT_ID);
-	
-	err = libusb_open(libusb_get_device(dev_handler), &dev_handler);
-	if (err != 0) {
-		perror("libusb_open");
-		exit(-1);
-	}
-
-	err = libusb_kernel_driver_active(dev_handler, 0);
-	if (err != 0) {
-		libusb_detach_kernel_driver(dev_handler, 0);
-		detached = true;
-	}
-
-	err = libusb_claim_interface(dev_handler, 0);
-	if (err != 0)
-		perror("libusb_claim_interface");
-
-	/* Init END */
-
-
-	printer_initialize(dev_handler, true);
-
-	printer_feed(dev_handler, 0x10);
-
-	char* str = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccdddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd";
-	
-	printer_print(dev_handler, str, strlen(str));
-
-	printer_feed(dev_handler, 0x10);
-
-	printer_cut(dev_handler, false);
-
-
-	/* Cleanup BEGIN */
-
-	err = libusb_release_interface(dev_handler, 0);
-	if (err)
-		perror("libusb_release_interface");
-
-	if (detached)
-		libusb_attach_kernel_driver(dev_handler, 0);
-
-	libusb_close(dev_handler);
-
-	
-	libusb_exit(NULL);
-
-	/* Cleanup END */
 }

src/printer.c

@@ -1,7 +1,70 @@
 #include <stdio.h>
+#include <stdbool.h>
+#include <libusb-1.0/libusb.h>
 
 #include "printer.h"
 
+struct usb_state {
+	libusb_device_handle* dev;
+	bool kernel_detached;
+};
+
+struct usb_state usb_dev;
+
+int connect_to_printer(uint16_t vid, uint16_t pid)
+{
+	int err;
+	usb_dev.kernel_detached = false;
+
+	err = libusb_init_context(NULL, NULL, 0);
+	if (err) {
+		perror("libusb_init_context");
+		return err;
+	}
+
+	usb_dev.dev = libusb_open_device_with_vid_pid(NULL, vid, pid);
+
+	err = libusb_open(libusb_get_device(usb_dev.dev), &(usb_dev.dev));
+	if (err) {
+		perror("libusb_open");
+		return err;
+	}
+
+	err = libusb_kernel_driver_active(usb_dev.dev, 0);
+	if (err) {
+		libusb_detach_kernel_driver(usb_dev.dev, 0);
+		usb_dev.kernel_detached = true;
+	}
+
+	err = libusb_claim_interface(usb_dev.dev, 0);
+	if (err) {
+		perror("libusb_claim_interface");
+		return err;
+	}
+
+	return 0;	
+}
+
+int disconnect_from_printer(void)
+{
+	int err;
+
+	err = libusb_release_interface(usb_dev.dev, 0);
+	if (err) {
+		perror("libusb_release_interface");
+		return err;
+	}
+
+	if (usb_dev.kernel_detached)
+		libusb_attach_kernel_driver(usb_dev.dev, 0);
+
+	libusb_close(usb_dev.dev);
+
+	libusb_exit(NULL);
+
+	return 0;
+}
+
 void send_msg(libusb_device_handle* dev_handler, unsigned char* data, size_t len)
 {
 	int err = libusb_bulk_transfer(dev_handler, PRINTER_ENDPOINT, data, len, NULL, 0);
@@ -9,11 +72,11 @@ void send_msg(libusb_device_handle* dev_handler, unsigned char* data, size_t len
 		perror("libusb_bulk_transfer");
 }
 
-void printer_initialize(libusb_device_handle* dev_handler, bool beep)
+void printer_initialize(bool beep)
 {
 	unsigned char data[2] = {0x1B, 0x40}; // 0x1B 0x40 is printer initialize
 
-	send_msg(dev_handler, data, 2);
+	send_msg(usb_dev.dev, data, 2);
 
 
 	if (!beep)
@@ -21,29 +84,36 @@ void printer_initialize(libusb_device_handle* dev_handler, bool beep)
 
 	data[1] = 0x07; // 0x1B 0x07 is beep
 	for (int i = 0; i < 2; i++)
-		send_msg(dev_handler, data, 2);
+		send_msg(usb_dev.dev, data, 2);
 }
 
-void printer_feed(libusb_device_handle* dev_handler, uint8_t lines)
+void printer_clear(void)
+{
+	unsigned char data[1] = {0x10};
+
+	send_msg(usb_dev.dev, data, 1);
+}
+
+void printer_feed(uint8_t lines)
 {
 	unsigned char data[2] = {0x14, lines}; 
 	
-	send_msg(dev_handler, data, 2);
+	send_msg(usb_dev.dev, data, 2);
 }
 
-void printer_cut(libusb_device_handle* dev_handler, bool partial)
+void printer_cut(bool partial)
 {
 	unsigned char data[1] = {0x19};
 	if (partial)
 		data[0] = 0x1A;
 
-	send_msg(dev_handler, data, 1);
+	send_msg(usb_dev.dev, data, 1);
 }
 
-void printer_print(libusb_device_handle* dev_handler, char* text, size_t len)
+void printer_print(char* text, size_t len)
 {
-	send_msg(dev_handler, (unsigned char*) text, len);	
+	send_msg(usb_dev.dev, (unsigned char*) text, len);	
 
 	unsigned char data[1] = {0x17};
-	send_msg(dev_handler, data, 1);
+	send_msg(usb_dev.dev, data, 1);
 }

src/printer.h

@@ -10,17 +10,19 @@
 // would love for this to be cli arguments
 #define PRINTER_VENDOR_ID 0x0404
 #define PRINTER_PRODUCT_ID 0x0312
-
 #define PRINTER_ENDPOINT 0x02
 
-void send_msg(libusb_device_handle* dev_handler, unsigned char* data, size_t len);
+int connect_to_printer(uint16_t vid, uint16_t pid);
+int disconnect_from_printer(void);
 
-void printer_initialize(libusb_device_handle* dev_handler, bool beep);
+void printer_initialize(bool beep);
+void printer_clear(void);
 
-void printer_feed(libusb_device_handle* dev_handler, uint8_t lines);
+void printer_feed(uint8_t lines);
+void printer_cut(bool partial);
+void printer_print(char* text, size_t len);
 
-void printer_cut(libusb_device_handle* dev_handler, bool partial);
 
-void printer_print(libusb_device_handle* dev_handler, char* text, size_t len);
+#define SETUP_PRINTER(vid, pid) connect_to_printer(vid, pid); printer_initialize(true); printer_clear()
 
 #endif