Add sodium_hex2bin()

src/libsodium/include/sodium/utils.h

@@ -26,9 +26,15 @@ SODIUM_EXPORT
 int sodium_memcmp(const void * const b1_, const void * const b2_, size_t size);
 
 SODIUM_EXPORT
-char *sodium_bin2hex(char * const hex, const size_t hex_len,
+char *sodium_bin2hex(char * const hex, const size_t hex_maxlen,
                      const unsigned char * const bin, const size_t bin_len);
 
+SODIUM_EXPORT
+int sodium_hex2bin(unsigned char * const bin, const size_t bin_maxlen,
+                   const char * const hex, const size_t hex_len,
+                   const char * const ignore, size_t * const bin_len,
+                   const char ** const hex_end);
+
 #ifdef __cplusplus
 }
 #endif

src/libsodium/sodium/utils.c

@@ -2,6 +2,7 @@
 #ifndef __STDC_WANT_LIB_EXT1__
 # define __STDC_WANT_LIB_EXT1__ 1
 #endif
+#include <errno.h>
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -77,7 +78,7 @@ _sodium_alignedcalloc(unsigned char ** const unaligned_p, const size_t len)
 }
 
 char *
-sodium_bin2hex(char * const hex, const size_t hex_len,
+sodium_bin2hex(char * const hex, const size_t hex_maxlen,
                const unsigned char * const bin, const size_t bin_len)
 {
     static const char hexdigits[16] = {
@@ -87,7 +88,7 @@ sodium_bin2hex(char * const hex, const size_t hex_len,
     size_t            i = (size_t) 0U;
     size_t            j = (size_t) 0U;
 
-    if (bin_len >= SIZE_MAX / 2 || hex_len < bin_len * 2U) {
+    if (bin_len >= SIZE_MAX / 2 || hex_maxlen < bin_len * 2U) {
         abort();
     }
     while (i < bin_len) {
@@ -99,3 +100,55 @@ sodium_bin2hex(char * const hex, const size_t hex_len,
 
     return hex;
 }
+
+int
+sodium_hex2bin(unsigned char * const bin, const size_t bin_maxlen,
+               const char * const hex, const size_t hex_len,
+               const char * const ignore, size_t * const bin_len,
+               const char ** const hex_end)
+{
+    size_t        bin_pos = (size_t) 0U;
+    size_t        hex_pos = (size_t) 0U;
+    int           ret = 0;
+    unsigned char c;
+    unsigned char c_acc = 0U;
+    unsigned char c_num;
+    unsigned char c_val;
+    unsigned char state = 0U;
+
+    while (hex_pos < hex_len) {
+        c = (unsigned char) hex[hex_pos];
+        if ((c_num = c ^ 48U) < 10U) {
+            c_val = c_num;
+        } else if ((c_num = (c & ~32U)) > 64 && c_num < 71U) {
+            c_val = c_num - 55U;
+        } else if (ignore != NULL && strchr(ignore, c) != NULL && state == 0U) {
+            hex_pos++;
+            continue;
+        } else {
+            break;
+        }
+        if (bin_pos >= bin_maxlen) {
+            ret = -1;
+            errno = ERANGE;
+            break;
+        }
+        if (state == 0U) {
+            c_acc = c_val * 16U;
+        } else {
+            bin[bin_pos++] = c_acc | c_val;
+        }
+        state = ~state;
+        hex_pos++;
+    }
+    if (state != 0U) {
+        hex_pos--;
+    }
+    if (hex_end != NULL) {
+        *hex_end = &hex[hex_pos];
+    }
+    if (bin_len != NULL) {
+        *bin_len = bin_pos;
+    }
+    return ret;
+}

test/default/sodium_utils.c

@@ -9,6 +9,9 @@ int main(void)
   unsigned char buf1[1000];
   unsigned char buf2[1000];
   char          buf3[33];
+  unsigned char buf4[4];
+  const char   *hex;
+  size_t        bin_len;
 
   randombytes(buf1, sizeof buf1);
   memcpy(buf2, buf1, sizeof buf2);
@@ -23,5 +26,10 @@ int main(void)
   printf("%s\n", sodium_bin2hex(buf3, 33U,
                                 (const unsigned char *)
                                 "0123456789ABCDEF", 16U));
+  hex = "Cafe : 6942";
+  sodium_hex2bin(buf4, sizeof buf4, hex, strlen(hex), ": ", &bin_len, NULL);
+  printf("%zu:%02x%02x%02x%02x\n", bin_len,
+         buf4[0], buf4[1], buf4[2], buf4[3]);
+
   return 0;
 }

test/default/sodium_utils.exp

@@ -4,3 +4,4 @@
 0
 0
 30313233343536373839414243444546
+4:cafe6942