Treat all integer multiplier suffixes as base-2.

Originally both base-2 and base-10 were supported, but since
there seems to be little need for base-10 in XZ Utils, treat
everything as base-2 and also be more relaxed about the case
of the first letter of the suffix. Now xz will accept e.g.
KiB, Ki, k, K, kB, and KB, and interpret them all as 1024. The
recommended spelling of the suffixes are still KiB, MiB, and GiB.

1 files changed, 16 insertions, 26 deletions

diff --git a/src/xzdec/xzdec.c b/src/xzdec/xzdec.c
index 3b1ab0f1..8518d362 100644
--- a/src/xzdec/xzdec.c
+++ b/src/xzdec/xzdec.c
@@ -183,34 +183,24 @@ str_to_uint64(const char *value, uint64_t max)
 
 	if (*value != '\0') {
 		// Look for suffix.
-		static const struct {
-			const char name[4];
-			uint32_t multiplier;
-		} suffixes[] = {
-			{ "k",   1000 },
-			{ "kB",  1000 },
-			{ "M",   1000000 },
-			{ "MB",  1000000 },
-			{ "G",   1000000000 },
-			{ "GB",  1000000000 },
-			{ "Ki",  1024 },
-			{ "KiB", 1024 },
-			{ "Mi",  1048576 },
-			{ "MiB", 1048576 },
-			{ "Gi",  1073741824 },
-			{ "GiB", 1073741824 }
-		};
-
-		uint32_t multiplier = 0;
-		for (size_t i = 0; i < ARRAY_SIZE(suffixes); ++i) {
-			if (strcmp(value, suffixes[i].name) == 0) {
-				multiplier = suffixes[i].multiplier;
-				break;
-			}
-		}
+		uint64_t multiplier = 0;
+		if (*value == 'k' || *value == 'K')
+			multiplier = UINT64_C(1) << 10;
+		else if (*value == 'm' || *value == 'M')
+			multiplier = UINT64_C(1) << 20;
+		else if (*value == 'g' || *value == 'G')
+			multiplier = UINT64_C(1) << 30;
+
+		++value;
+
+		// Allow also e.g. Ki, KiB, and KB.
+		if (*value != '\0' && strcmp(value, "i") != 0
+				&& strcmp(value, "iB") != 0
+				&& strcmp(value, "B") != 0)
+			multiplier = 0;
 
 		if (multiplier == 0) {
-			my_errorf("%s: Invalid suffix", value);
+			my_errorf("%s: Invalid suffix", value - 1);
 			exit(EXIT_FAILURE);
 		}