From 54c29f3214d9ad43bd0eeab1ff025af8bfbf1309 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: May 23 2020 05:59:01 +0000
Subject: driver: implemented block-size logic.


---

diff --git a/include/tpax/tpax.h b/include/tpax/tpax.h
index 7c8404b..0be10f9 100644
--- a/include/tpax/tpax.h
+++ b/include/tpax/tpax.h
@@ -101,6 +101,7 @@ struct tpax_common_ctx {
 	uint64_t			drvflags;
 	uint64_t			actflags;
 	uint64_t			fmtflags;
+	uint32_t			blksize;
 };
 
 struct tpax_driver_ctx {
diff --git a/src/driver/tpax_driver_ctx.c b/src/driver/tpax_driver_ctx.c
index 675d836..81c4e34 100644
--- a/src/driver/tpax_driver_ctx.c
+++ b/src/driver/tpax_driver_ctx.c
@@ -5,6 +5,7 @@
 /******************************************************/
 
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -84,7 +85,7 @@ static int tpax_driver_usage(
 		"Synopsis:\n"
 		"       %s\n"
 		"       %s -r\n"
-		"       %s -w [−x format]\n"
+		"       %s -w [−x format] [-b blocksize]\n"
 		"       %s -r -w\n\n"
 		"Options:\n",
 		program,program,program,program,program);
@@ -192,6 +193,44 @@ static int tpax_driver_usage_write_format(
 	return TPAX_USAGE;
 }
 
+static int tpax_driver_usage_block_size(
+	int				fdout,
+	const char *			program,
+	const char *			arg,
+	const struct argv_option **	optv,
+	struct argv_meta *		meta)
+{
+	tpax_driver_usage(
+		fdout,program,
+		arg,optv,meta);
+
+	tpax_dprintf(
+		fdout,
+		"`%s' is not a valid positive decimal integer.\n",
+		arg);
+
+	return TPAX_USAGE;
+}
+
+static int tpax_driver_usage_block_size_range(
+	int				fdout,
+	const char *			program,
+	const char *			arg,
+	const struct argv_option **	optv,
+	struct argv_meta *		meta)
+{
+	tpax_driver_usage(
+		fdout,program,
+		arg,optv,meta);
+
+	tpax_dprintf(
+		fdout,
+		"`%s' is outside the specified range of 512 to 32256.\n",
+		arg);
+
+	return TPAX_USAGE;
+}
+
 static int tpax_driver_error_not_implemented(
 	int				fdout,
 	const char *			program,
@@ -267,6 +306,7 @@ int tpax_get_driver_ctx(
 	size_t				nunits;
 	const char *			program;
 	int				fddst;
+	const char *			ch;
 
 	(void)envp;
 
@@ -334,6 +374,27 @@ int tpax_get_driver_ctx(
 						cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_RUSTAR;
 
 					break;
+
+				case TAG_BLKSIZE:
+					ch = (entry->arg[0] == '+')
+						? &entry->arg[1]
+						: entry->arg;
+
+					for (; *ch; ch++)
+						if ((*ch < '0') || (*ch > '9'))
+							return tpax_driver_usage_block_size(
+								fdctx->fdout,
+								program,entry->arg,
+								optv,meta);
+
+					cctx.blksize = atoi(entry->arg);
+
+					if ((cctx.blksize < 512) || (cctx.blksize > 32256))
+						return tpax_driver_usage_block_size_range(
+							fdctx->fdout,
+							program,entry->arg,
+							optv,meta);
+					break;
 			}
 		} else {
 			operand = entry;
diff --git a/src/internal/tpax_driver_impl.h b/src/internal/tpax_driver_impl.h
index d061474..0a5c583 100644
--- a/src/internal/tpax_driver_impl.h
+++ b/src/internal/tpax_driver_impl.h
@@ -27,6 +27,7 @@ enum app_tags {
 	TAG_WRITE,
 	TAG_COPY,
 	TAG_FORMAT,
+	TAG_BLKSIZE,
 };
 
 struct tpax_driver_ctx_impl {
diff --git a/src/skin/tpax_skin_default.c b/src/skin/tpax_skin_default.c
index 69179be..dacc9d8 100644
--- a/src/skin/tpax_skin_default.c
+++ b/src/skin/tpax_skin_default.c
@@ -26,5 +26,13 @@ const struct argv_option tpax_default_options[] = {
 			"pax|cpio|ustar|rustar",0,
 			"archive format [%s]"},
 
+	{"blksize",	'b',TAG_BLKSIZE,ARGV_OPTARG_REQUIRED,0,0,0,
+			"(non-default) block-size; valid values are "
+			"in the range of 512 to 32256; keeping "
+			"the default format-specific block size "
+			"(5120 for the pax and cpio formats,"
+			" 10240 for the ustar format) "
+			"is strongly recommended."},
+
 	{0,0,0,0,0,0,0,0}
 };