Changeset cc9f314 in mainline

Timestamp:

2012-03-27T13:13:06Z (12 years ago)

Author:

Vojtech Horky <vojtechhorky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a9a6d8d

Parents:

9bdf1f2a

git-author:

Taylor Killian <> (2012-03-27 13:13:06)

git-committer:

Vojtech Horky <vojtechhorky@…> (2012-03-27 13:13:06)

Message:

Implement head and tail functionality in bdsh/cat (thx Taylor Killian)

This patch fixes a number of problems in the cat app. Most
importantly, it correctly displays characters at the end of the read
buffer, where previously multibyte characters were being rendered as
U_SPECIAL. It also implements the buffer size argument (-b) that the
—help mentions. The size of the buffer must be at least 4 though in
order to accommodate multibyte characters. Finally head (-H) and tail
(-t) were implemented as per —help.

Location:

uspace/app/bdsh/cmds/modules/cat

Files:

• cat.c (modified) (10 diffs)
• cat.h (modified) (1 diff)

uspace/app/bdsh/cmds/modules/cat/cat.c

@@ -52 +52 @@
 #define CAT_VERSION "0.0.1"
 #define CAT_DEFAULT_BUFLEN 1024
-
-static const char *cat_oops = "That option is not yet supported\n";
+#define CAT_FULL_FILE 0
+
 static const char *hexchars = "0123456789abcdef";
 
@@ -163 +163 @@
 }
 
-static unsigned int cat_file(const char *fname, size_t blen, bool hex)
+static unsigned int cat_file(const char *fname, size_t blen, bool hex,
+    off64_t head, off64_t tail, bool tail_first)
 {
         int fd, bytes = 0, count = 0, reads = 0;
         char *buff = NULL;
         int i;
-        size_t offset = 0;
+        size_t offset = 0, copied_bytes = 0;
+        off64_t file_size = 0, length = 0;
 
         fd = open(fname, O_RDONLY);
@@ -183 +185 @@
         }
 
+        if (tail != CAT_FULL_FILE) {
+                file_size = lseek(fd, 0, SEEK_END);
+                if (head == CAT_FULL_FILE) {
+                        head = file_size;
+                        length = tail;
+                } else if (tail_first) {
+                        length = head;
+                } else {
+                        if (tail > head)
+                                tail = head;
+                        length = tail;
+                }
+
+                if (tail_first) {
+                        lseek(fd, (tail >= file_size) ? 0 : (file_size - tail), SEEK_SET);
+                } else {
+                        lseek(fd, ((head - tail) >= file_size) ? 0 : (head - tail), SEEK_SET);
+                }
+        } else
+                length = head;
+
         do {
-                bytes = read(fd, buff, blen);
+                bytes = read(fd, buff + copied_bytes, (
+                        (length != CAT_FULL_FILE && length - (off64_t)count <= (off64_t)(blen - copied_bytes)) ?
+                        (size_t)(length - count) :
+                        (blen - copied_bytes) ) );
+                bytes += copied_bytes;
+                copied_bytes = 0;
+
                 if (bytes > 0) {
-                        count += bytes;
                         buff[bytes] = '\0';
                         offset = 0;
@@ -193 +221 @@
                                         paged_char(hexchars[((uint8_t)buff[i])/16]);
                                         paged_char(hexchars[((uint8_t)buff[i])%16]);
+                                        paged_char(((count+i+1) & 0xf) == 0 ? '\n' : ' ');
                                 }
                                 else {
@@ -199 +228 @@
                                                 /* Reached end of string */
                                                 break;
+                                        } else if (c == U_SPECIAL && offset + 2 >= (size_t)bytes) {
+                                                /* If an extended character is cut off due to the size of the buffer,
+                                                   we will copy it over to the next buffer so it can be read correctly. */
+                                                copied_bytes = bytes - offset + 1;
+                                                memcpy(buff, buff + offset - 1, copied_bytes);
+                                                break;
                                         }
                                         paged_char(c);
@@ -204 +239 @@
                                 
                         }
+                        count += bytes;
                         reads++;
                 }
-        } while (bytes > 0 && !should_quit);
+        } while (bytes > 0 && !should_quit && (count < length || length == CAT_FULL_FILE));
 
         close(fd);
@@ -223 +259 @@
 int cmd_cat(char **argv)
 {
-        unsigned int argc, i, ret = 0, buffer = 0;
+        unsigned int argc, i, ret = 0;
+        size_t buffer = 0;
         int c, opt_ind;
+        aoff64_t head = CAT_FULL_FILE, tail = CAT_FULL_FILE;
         bool hex = false;
         bool more = false;
+        bool tailFirst = false;
         sysarg_t rows, cols;
         int rc;
@@ -254 +293 @@
                         return CMD_SUCCESS;
                 case 'H':
-                        printf("%s", cat_oops);
-                        return CMD_FAILURE;
+                        if (!optarg || str_uint64_t(optarg, NULL, 10, false, &head) != EOK ) {
+                                puts("Invalid head size\n");
+                                return CMD_FAILURE;
+                        }
+                        break;
                 case 't':
-                        printf("%s", cat_oops);
-                        return CMD_FAILURE;
+                        if (!optarg || str_uint64_t(optarg, NULL, 10, false, &tail) != EOK ) {
+                                puts("Invalid tail size\n");
+                                return CMD_FAILURE;
+                        }
+                        if (head == CAT_FULL_FILE)
+                                tailFirst = true;
+                        break;
                 case 'b':
-                        printf("%s", cat_oops);
+                        if (!optarg || str_size_t(optarg, NULL, 10, false, &buffer) != EOK ) {
+                                puts("Invalid buffer size\n");
+                                return CMD_FAILURE;
+                        }
                         break;
                 case 'm':
@@ -279 +329 @@
         }
 
-        if (buffer <= 0)
+        if (buffer < 4)
                 buffer = CAT_DEFAULT_BUFLEN;
         
@@ -295 +345 @@
 
         for (i = optind; argv[i] != NULL && !should_quit; i++)
-                ret += cat_file(argv[i], buffer, hex);
+                ret += cat_file(argv[i], buffer, hex, head, tail, tailFirst);
 
         if (ret)

uspace/app/bdsh/cmds/modules/cat/cat.h

@@ -4 +4 @@
 /* Prototypes for the cat command, excluding entry points */
 
-static unsigned int cat_file(const char *, size_t, bool);
+static unsigned int cat_file(const char *, size_t, bool, off64_t, off64_t, bool);
 
 #endif /* CAT_H */