join: code shrink (4)join2

The user supplies field numbers with the -o, -1 and -2 options.
It feels more natural to convert these to 0-based field indices
in the code.

Saves 32-48 bytes.

Signed-off-by: Ron Yorston <rmy@pobox.com>

1 files changed, 26 insertions, 25 deletions

diff --git a/coreutils/join.c b/coreutils/join.c
index 7265452cd..370003d21 100644
--- a/coreutils/join.c
+++ b/coreutils/join.c
@@ -53,12 +53,12 @@ typedef struct {
 
 typedef struct {
         FILE *fp;
-        int idx;
-        const char *field; /* this is a pointer to lines[0].fields[idx - 1] or "" */
+        int idx;                        /* index of join field in fields array */
+        const char *field;      /* pointer to lines[0].fields[idx] or "" */
         LINE *lines;
         LINE pushback;
-        int linecount;
-        int linecap;
+        int linecount;          /* number of lines currently cached */
+        int linecap;            /* current capacity of lines array */
 } FDAT;
 
 static int field_split(char *s, char sep, char ***fields)
@@ -153,10 +153,10 @@ static void readfields(char sep, FDAT *f)
                 }
 
                 /* Ensure strcmp() matches on first pass through loop */
-                if (f->idx > curr.fieldcount)
+                if (f->idx >= curr.fieldcount)
                         field2 = "";
                 else
-                        field2 = (curr.fields)[f->idx - 1];
+                        field2 = (curr.fields)[f->idx];
 
                 if (first)
                         f->field = field2;
@@ -192,7 +192,7 @@ static void printfields(int *format, const char *empty_str, char sep, FDAT *f1,
         int linef2;
         int fn;
         int format_fl;
-        int format_no;
+        int format_idx;
         bool first;
 
         LINE *l1;
@@ -221,16 +221,16 @@ static void printfields(int *format, const char *empty_str, char sep, FDAT *f1,
                                                 bb_putchar(sep);
 
                                         format_fl = format[0];
-                                        format_no = format[1];
+                                        format_idx = format[1];
 
                                         if (format_fl == 1) {
-                                                if (l1 != NULL && l1->fieldcount >= format_no && format_no > 0)
-                                                        fputs_stdout(fieldorempty(l1->fields[format_no - 1], empty_str));
+                                                if (l1 != NULL && l1->fieldcount > format_idx)
+                                                        fputs_stdout(fieldorempty(l1->fields[format_idx], empty_str));
                                                 else
                                                         fputs_stdout(empty_str);
                                         } else if (format_fl == 2) {
-                                                if (l2 != NULL && l2->fieldcount >= format_no && format_no > 0)
-                                                        fputs_stdout(fieldorempty(l2->fields[format_no - 1], empty_str));
+                                                if (l2 != NULL && l2->fieldcount > format_idx)
+                                                        fputs_stdout(fieldorempty(l2->fields[format_idx], empty_str));
                                                 else
                                                         fputs_stdout(empty_str);
                                         } else
@@ -241,22 +241,22 @@ static void printfields(int *format, const char *empty_str, char sep, FDAT *f1,
                         } else {
                                 fputs_stdout(fieldorempty(field, empty_str));
 
-                                fn = 1;
+                                fn = 0;
                                 if (l1 != NULL)
-                                        while (l1->fields[fn - 1]) {
+                                        while (l1->fields[fn]) {
                                                 if (fn != f1->idx) {
                                                         bb_putchar(sep);
-                                                        fputs_stdout(fieldorempty(l1->fields[fn - 1], empty_str));
+                                                        fputs_stdout(fieldorempty(l1->fields[fn], empty_str));
                                                 }
                                                 fn++;
                                         }
 
-                                fn = 1;
+                                fn = 0;
                                 if (l2 != NULL)
-                                        while (l2->fields[fn - 1]) {
+                                        while (l2->fields[fn]) {
                                                 if (fn != f2->idx) {
                                                         bb_putchar(sep);
-                                                        fputs_stdout(fieldorempty(l2->fields[fn - 1], empty_str));
+                                                        fputs_stdout(fieldorempty(l2->fields[fn], empty_str));
                                                 }
                                                 fn++;
                                         }
@@ -269,7 +269,7 @@ static void printfields(int *format, const char *empty_str, char sep, FDAT *f1,
 static void parsejformat(int **format_p, const char *format_str)
 {
         int *format;
-        int field_no;
+        int field_idx;
 
         char scache[20] = { 0 };
 
@@ -306,11 +306,11 @@ static void parsejformat(int **format_p, const char *format_str)
                                 bb_simple_error_msg_and_die("field specifier too large");
                         memcpy(scache, format_str + 2, sn - 2);
                         scache[sn - 2] = '\0';
-                        field_no = xatoi_positive(scache);
-                        if (field_no <= 0)
+                        field_idx = xatoi_positive(scache);
+                        if (--field_idx < 0)
                                 bb_simple_error_msg_and_die("field number can't be 0");
                         format[n * 2] = *format_str - '0';
-                        format[n * 2 + 1] = field_no;
+                        format[n * 2 + 1] = field_idx;
                 } else {
                         bb_simple_error_msg_and_die("field specifier must be 0, 1.x or 2.x");
                 }
@@ -337,7 +337,7 @@ int join_main(int argc, char **argv)
 
         FDAT f1 = {
                 .fp = NULL,
-                .idx = 1,
+                .idx = 0,
                 .field = NULL,
                 .lines = NULL,
                 .pushback = { .fields = NULL, .fieldcount = 0 },
@@ -346,7 +346,7 @@ int join_main(int argc, char **argv)
         };
         FDAT f2 = {
                 .fp = NULL,
-                .idx = 1,
+                .idx = 0,
                 .field = NULL,
                 .lines = NULL,
                 .pushback = { .fields = NULL, .fieldcount = 0 },
@@ -389,7 +389,8 @@ int join_main(int argc, char **argv)
                 }
         }
 
-        if (f1.idx < 1 || f2.idx < 1)
+        if (((opts & FLAG_FIELD_1) && --f1.idx < 0) ||
+                        ((opts & FLAG_FIELD_2) && --f2.idx < 0))
                 bb_simple_error_msg_and_die("field 0 doesn't exist");
 
         if (opts & FLAG_SEP_USED) {