- usb.c: allocate mem as pci.c does

- usb.c: kill dead code
- usb.c: give url to get info on /proc/bus/usb/devices format
- usb.c: the /proc/bus/usb/devices really is a state machine;
  use switch to make it clearer
- {usb,pci}.c: r.nb is zeroed in all path, let's do it only time

1 files changed, 31 insertions, 32 deletions

diff --git a/usb.c b/usb.c
index 75712b4..7a8f751 100644
--- a/usb.c
+++ b/usb.c
@@ -14,12 +14,11 @@ extern struct pciusb_entries usb_probe(void) {
 	FILE *f;
 	char buf[BUF_SIZE];
 	int line;
-	struct pciusb_entry t[MAX_DEVICES];
 	struct pciusb_entries r;
 	struct pciusb_entry *e = NULL;
-
+	r.nb = 0;
 	if (access(proc_pci_path, R_OK) != 0) {
-		r.nb = 0; r.entries = NULL;
+		r.entries = NULL;
 		return r;
 	}
 
@@ -31,49 +30,48 @@ extern struct pciusb_entries usb_probe(void) {
 				    "fopen() sets errno to", proc_usb_path);
 			perror(err_msg);
 			free(err_msg);
-		} /*else {
-			asprintf(&err_msg, "unable to open \"%s\"\n"
-				    "You should enable the usb service (as root, type 'service usb start'.\n"
-				    "fopen() sets errno to", proc_usb_path);
-			perror(err_msg);
-			free(err_msg);
-		} */
-		r.nb = 0; r.entries = NULL;
+		}
+		r.entries = NULL;
 		return r;
 	}
-  
-	for(r.nb = 0, line = 1; fgets(buf, sizeof(buf) - 1, f) && r.nb < psizeof(t); line++) {
-		if (buf[0] == 'T') {
-		        unsigned short pci_bus, pci_device;
-			e = &t[r.nb++];
+
+	r.entries = malloc(sizeof(struct pciusb_entry) * MAX_DEVICES);
+	/* for further information on the format parsed by this state machine,
+	 * read /usr/share/doc/kernel-doc-X.Y.Z/usb/proc_usb_info.txt */  
+	for(line = 1; fgets(buf, sizeof(buf) - 1, f) && r.nb < MAX_DEVICES; line++) {
+
+		switch (buf[0]) {
+		case 'T': {
+			unsigned short pci_bus, pci_device;
+			e = &r.entries[r.nb++];
 			pciusb_initialize(e);
 
 			if (sscanf(buf, "T:  Bus=%02hd Lev=%*02d Prnt=%*02d Port=%*02d Cnt=%*02d Dev#=%3hd Spd=%*3s MxCh=%*2d", &pci_bus, &pci_device) == 2) {
 				e->pci_bus = pci_bus;
 				e->pci_device = pci_device;
-			} else {
-				fprintf(stderr, "%s %d: unknown ``T'' line\n", proc_usb_path, line);
-			}
-
-		} else if (buf[0] == 'P') {
-		        unsigned short vendor, device;
+			} else fprintf(stderr, "%s %d: unknown ``T'' line\n", proc_usb_path, line);
+			break;
+		}
+		case 'P': {
+			unsigned short vendor, device;
 			if (sscanf(buf, "P:  Vendor=%hx ProdID=%hx", &vendor, &device) == 2) {
 				e->vendor = vendor;
 				e->device = device;
-			} else {
-				fprintf(stderr, "%s %d: unknown ``P'' line\n", proc_usb_path, line);
-			}
-		} else if (e && buf[0] == 'I' && e->class_ == 0) {
+			} else fprintf(stderr, "%s %d: unknown ``P'' line\n", proc_usb_path, line);
+			break;
+		}
+		case 'I': if (e->class_ == 0) {
 			int class_, sub, prot = 0;
 			if (sscanf(buf, "I:  If#=%*2d Alt=%*2d #EPs=%*2d Cls=%02x(%*5c) Sub=%02x Prot=%02x", &class_, &sub, &prot) == 3) {
 				e->class_ = (class_ * 0x100 + sub) * 0x100 + prot;
+				/* see linux/sound/usb/usbaudio.c::usb_audio_ids */
 				if (e->class_ == (0x1*0x100+ 0x01)) /* USB_AUDIO_CLASS*0x100 + USB_SUBCLASS_AUDIO_CONTROL*/
 					e->module = "snd-usb-audio";
 
-			} else {
-				fprintf(stderr, "%s %d: unknown ``I'' line\n", proc_usb_path, line);
-			}
-		} else if (e && buf[0] == 'S') {
+			} else fprintf(stderr, "%s %d: unknown ``I'' line\n", proc_usb_path, line);
+			break;
+		}
+		case 'S': {
 			int offset;
 			char dummy;
 			size_t length = strlen(buf) -1;
@@ -83,14 +81,15 @@ extern struct pciusb_entries usb_probe(void) {
 			} else if (sscanf(buf, "S:  Product=%n%c", &offset, &dummy) == 1) {
 				if (!e->text) 
 					e->text = strdup("Unknown|");
-				buf[length - 1] = 0; /* removing '\n' */
+ 				buf[length - 1] = 0; /* removing '\n' */
 				e->text = realloc(e->text, strlen(e->text) + length-offset + 2);
 				strcat(e->text, buf + offset);
 			}
 		}
+		}
 	}
 	fclose(f);
-	r.entries = memdup(t, sizeof(struct pciusb_entry) * r.nb);
+	realloc(r.entries,  sizeof(struct pciusb_entry) * r.nb);
 
 	pciusb_find_modules(&r, "usbtable", 1 /* no_subid */);
 	return r;