bc: code shrink in zbc_lex_number()

function                                             old     new   delta
zbc_lex_number                                       279     190     -89

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/miscutils/bc.c b/miscutils/bc.c
index 6ab3a42524119f97a17653e92ea5a7b4109b23ab..5a4c92a1c97da834d20e42abc8d57e97f09078f7 100644 (file)
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -2976,29 +2976,40 @@ static void bc_lex_whitespace(BcLex *l)
 static BC_STATUS zbc_lex_number(BcLex *l, char start)
 {
        const char *buf = l->buf + l->i;
-       size_t len, hits = 0, bslashes = 0, i = 0, j;
-       char c = buf[i];
-       bool last_pt, pt = start == '.';
+       size_t len, bslashes, i, ccnt;
+       bool pt;
 
-       last_pt = pt;
+       pt = (start == '.');
        l->t.t = BC_LEX_NUMBER;
-
-       while (c != 0 && (isdigit(c) || (c >= 'A' && c <= 'F') ||
-                         (c == '.' && !pt) || (c == '\\' && buf[i + 1] == '\n')))
-       {
-               if (c != '\\') {
-                       last_pt = c == '.';
-                       pt = pt || last_pt;
+       bslashes = 0;
+       ccnt = i = 0;
+       for (;;) {
+               char c = buf[i];
+               if (c == '\0')
+                       break;
+               if (c == '\\' && buf[i + 1] == '\n') {
+                       i += 2;
+                       bslashes++;
+                       continue;
                }
-               else {
-                       ++i;
-                       bslashes += 1;
+               if (!isdigit(c) && (c < 'A' || c > 'F')) {
+                       if (c != '.') break;
+                       // if '.' was already seen, stop on second one:
+                       if (pt) break;
+                       pt = 1;
                }
-
-               c = buf[++i];
+               // buf[i] is one of "0-9A-F."
+               i++;
+               if (c != '.')
+                       ccnt = i;
        }
+       //i is buf[i] index of the first not-yet-parsed char
+       l->i += i;
+
+       //ccnt is the number of chars in the number string, excluding possible
+       //trailing "." and possible following trailing "\<newline>"(s).
+       len = ccnt - bslashes * 2 + 1; // +1 byte for NUL termination
 
-       len = i + !last_pt - bslashes * 2;
        // This check makes sense only if size_t is (much) larger than BC_MAX_NUM.
        if (SIZE_MAX > (BC_MAX_NUM | 0xff)) {
                if (len > BC_MAX_NUM)
@@ -3006,26 +3017,23 @@ static BC_STATUS zbc_lex_number(BcLex *l, char start)
        }
 
        bc_vec_pop_all(&l->t.v);
-       bc_vec_expand(&l->t.v, len + 1);
+       bc_vec_expand(&l->t.v, 1 + len);
        bc_vec_push(&l->t.v, &start);
 
-       for (buf -= 1, j = 1; j < len + hits * 2; ++j) {
-
-               c = buf[j];
-
+       while (ccnt != 0) {
                // If we have hit a backslash, skip it. We don't have
                // to check for a newline because it's guaranteed.
-               if (hits < bslashes && c == '\\') {
-                       ++hits;
-                       ++j;
+               if (*buf == '\\') {
+                       buf += 2;
+                       ccnt -= 2;
                        continue;
                }
-
-               bc_vec_push(&l->t.v, &c);
+               bc_vec_push(&l->t.v, buf);
+               buf++;
+               ccnt--;
        }
 
        bc_vec_pushZeroByte(&l->t.v);
-       l->i += i;
 
        RETURN_STATUS(BC_STATUS_SUCCESS);
 }