shell: clarify help text of CONFIG_{SH,BASH}_IS_* options

[oweals/busybox.git] / libbb / crc32.c

diff --git a/libbb/crc32.c b/libbb/crc32.c
index 1e4a57e8a27ef6d6f75ce5498102c42331930a53..ac9836cc9e61b185e08687e75c73c380fc751762 100644 (file)
--- a/libbb/crc32.c
+++ b/libbb/crc32.c
@@ -12,18 +12,23 @@
  *
  * endian = 1: big-endian
  * endian = 0: little-endian
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
 
 #include "libbb.h"
 
-uint32_t *crc32_filltable(int endian)
-{
+uint32_t *global_crc32_table;
 
-       uint32_t *crc_table = xmalloc(256 * sizeof(uint32_t));
+uint32_t* FAST_FUNC crc32_filltable(uint32_t *crc_table, int endian)
+{
        uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320;
        uint32_t c;
        int i, j;
 
+       if (!crc_table)
+               crc_table = xmalloc(256 * sizeof(uint32_t));
+
        for (i = 0; i < 256; i++) {
                c = endian ? (i << 24) : i;
                for (j = 8; j; j--) {
@@ -37,3 +42,25 @@ uint32_t *crc32_filltable(int endian)
 
        return crc_table - 256;
 }
+
+uint32_t FAST_FUNC crc32_block_endian1(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table)
+{
+       const void *end = (uint8_t*)buf + len;
+
+       while (buf != end) {
+               val = (val << 8) ^ crc_table[(val >> 24) ^ *(uint8_t*)buf];
+               buf = (uint8_t*)buf + 1;
+       }
+       return val;
+}
+
+uint32_t FAST_FUNC crc32_block_endian0(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table)
+{
+       const void *end = (uint8_t*)buf + len;
+
+       while (buf != end) {
+               val = crc_table[(uint8_t)val ^ *(uint8_t*)buf] ^ (val >> 8);
+               buf = (uint8_t*)buf + 1;
+       }
+       return val;
+}