diff: debug macros; one trivial size optimization

function                                             old     new   delta
diffreg                                             1781    1815     +34
isqrt                                                 64       -     -64
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/0 up/down: 34/-64)            Total: -30 bytes

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

diff --git a/editors/diff.c b/editors/diff.c
index 42aba9ae0e29a8b0835cf14acd29dfe0354c54ad..e977f4d14cb077cddd6159de9c55dfd3affda00d 100644 (file)
--- a/editors/diff.c
+++ b/editors/diff.c
@@ -14,6 +14,9 @@
 
 #include "libbb.h"
 
+#define dbg_error_msg(...) ((void)0)
+//#define dbg_error_msg(...) bb_error_msg(__VA_ARGS__)
+
 // #define FSIZE_MAX 32768
 
 /* NOINLINEs added to prevent gcc from merging too much into diffreg()
@@ -474,12 +477,13 @@ static int stone(int *a, int n, int *b, int *c)
 {
        int i, k, y, j, l;
        int oldc, tc, oldl;
-       unsigned int numtries;
+       unsigned numtries;
+       int isq = isqrt(n);
 #if ENABLE_FEATURE_DIFF_MINIMAL
-       const unsigned int bound =
-               (option_mask32 & FLAG_d) ? UINT_MAX : MAX(256, isqrt(n));
+       const unsigned bound =
+               (option_mask32 & FLAG_d) ? UINT_MAX : MAX(256, isq);
 #else
-       const unsigned int bound = MAX(256, isqrt(n));
+       const unsigned bound = MAX(256, isq);
 #endif
 
        k = 0;
@@ -769,6 +773,8 @@ static void dump_unified_vec(FILE *f1, FILE *f2)
        if (context_idx < 0)
                return;
 
+       dbg_error_msg("dumping %d context_vecs", context_idx+1);
+
        b = d = 0;                      /* gcc */
        lowa = MAX(1, cvp->a - opt_U_context);
        upb = MIN(nlen[0], context_vector[context_idx].b + opt_U_context);
@@ -860,6 +866,10 @@ static void change(const char *file1, FILE *f1, const char *file2, FILE *f2,
                        int a, int b, int c, int d)
 {
        if ((a > b && c > d) || (option_mask32 & FLAG_q)) {
+//compat BUG: "diff -ub F1 F2" will output nothing, but will exit 1
+//if F1 and F2 differ only in whitespace. "standard" diff exits 0.
+//This is the place where this erroneous exitcode is set:
+               dbg_error_msg("%d: abcd:%d,%d,%d,%d, anychange=1", __LINE__, a,b,c,d);
                anychange = 1;
                return;
        }
@@ -885,6 +895,7 @@ static void change(const char *file1, FILE *f1, const char *file2, FILE *f2,
        context_vector[context_idx].b = b;
        context_vector[context_idx].c = c;
        context_vector[context_idx].d = d;
+       dbg_error_msg("new context_vec[%d]:%d,%d,%d,%d", context_idx, a,b,c,d);
        anychange = 1;
 }
 
@@ -1074,6 +1085,7 @@ static unsigned diffreg(const char *file1, const char *file2, int flags)
  closem:
        if (anychange) {
                exit_status |= 1;
+               dbg_error_msg("exit_status|=1 = %d", exit_status);
                if (rval == D_SAME)
                        rval = D_DIFFER;
        }