Re-worked the support for s///p, fixed a backref limit buglet, and cleaned up

a few other ugly places (do_subst_command got a much-needed overhaul). Also
took out BB_FEATURE_SED_PATTERN_SPACE from Config.h[.Hurd] as the 'p' is now a
standard feature (adds almost no bloat).

4 files changed, 172 insertions, 148 deletions

diff --git a/Config.h b/Config.h
index a111feeda..b2baac2a2 100644
--- a/Config.h
+++ b/Config.h
@@ -223,9 +223,6 @@
 // Enable support for "--exclude" for excluding files
 #define BB_FEATURE_TAR_EXCLUDE
 //
-// Enable support for s///p pattern matching
-#define BB_FEATURE_SED_PATTERN_SPACE
-//
 //// Enable reverse sort
 #define BB_FEATURE_SORT_REVERSE
 //
diff --git a/Config.h.Hurd b/Config.h.Hurd
index 79fdff6ad..9238761a2 100644
--- a/Config.h.Hurd
+++ b/Config.h.Hurd
@@ -218,9 +218,6 @@
 // Enable support for "--exclude" for excluding files
 #define BB_FEATURE_TAR_EXCLUDE
 //
-// Enable support for s///p pattern matching
-#define BB_FEATURE_SED_PATTERN_SPACE
-//
 //// Enable reverse sort
 #define BB_FEATURE_SORT_REVERSE
 //
diff --git a/editors/sed.c b/editors/sed.c
index 75435f67a..eaca9ada5 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -62,13 +62,12 @@ extern char *optarg; /* ditto */
 /* options */
 static int be_quiet = 0;
 
-static const int SUB_G = 1 << 0;
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-static const int SUB_P = 1 << 1;
-#endif
 
 struct sed_cmd {
 
+
+        /* GENERAL FIELDS */
+
         /* address storage */
         int beg_line; /* 'sed 1p'   0 == no begining line, apply commands to all lines */
         int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
@@ -78,19 +77,21 @@ struct sed_cmd {
         /* the command */
         char cmd; /* p,d,s (add more at your leisure :-) */
 
-        /* substitution command specific fields */
-        regex_t *sub_match; /* sed -e 's/sub_match/replace/' */
-        char *replace; /* sed -e 's/sub_match/replace/' XXX: who will hold the \1 \2 \3s? */
+
+        /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
+
+        /* sed -e 's/sub_match/replace/' */
+        regex_t *sub_match;
+        char *replace;
         unsigned int num_backrefs:4; /* how many back references (\1..\9) */
                         /* Note:  GNU/POSIX sed does not save more than nine backrefs, so
                          * we only use 4 bits to hold the number */
-#ifndef BB_FEATURE_SED_PATTERN_SPACE
-        unsigned int sub_flags:1; /* sed -e 's/foo/bar/g' (global) */
-#else
-        unsigned int sub_flags:2; /* sed -e 's/foo/bar/gp' (global/pattern) */
-#endif
+        unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
+        unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
+
+
+        /* EDIT COMMAND (a,i,c) SPEICIFIC FIELDS */
 
-        /* edit command (a,i,c) speicific field */
         char *editline;
 };
 
@@ -278,7 +279,7 @@ static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
         /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */ 
         for (j = 0; match[j]; j++) {
                 /* GNU/POSIX sed does not save more than nine backrefs */
-                if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs < 9)
+                if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
                         sed_cmd->num_backrefs++;
         }
 
@@ -293,16 +294,14 @@ static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
         while (substr[++idx]) {
                 switch (substr[idx]) {
                         case 'g':
-                                sed_cmd->sub_flags = SUB_G;
+                                sed_cmd->sub_g = 1;
                                 break;
                         case 'I':
                                 cflags |= REG_ICASE;
                                 break;
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
                         case 'p':
-                                sed_cmd->sub_flags = SUB_P;
+                                sed_cmd->sub_p = 1;
                                 break;
-#endif
                         default:
                                 /* any whitespace or semicolon trailing after a s/// is ok */
                                 if (strchr("; \t\v\n\r", substr[idx]))
@@ -534,59 +533,53 @@ static void print_subst_w_backrefs(const char *line, const char *replace, regmat
 
 static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
 {
+        char *hackline = (char *)line;
         int altered = 0;
+        regmatch_t *regmatch = NULL;
 
-        /* we only substitute if the substitution 'search' expression matches */
-        if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == 0) {
-                regmatch_t *regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
-                int i;
-                char *ptr = (char *)line;
-
-                while (*ptr) {
-                        /* if we can match the search string... */
-                        if (regexec(sed_cmd->sub_match, ptr, sed_cmd->num_backrefs+1, regmatch, 0) == 0) {
-                                /* print everything before the match, */
-                                for (i = 0; i < regmatch[0].rm_so; i++) {
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                                        if(!be_quiet || (sed_cmd->sub_flags & SUB_P))
-#endif
-                                        fputc(ptr[i], stdout);
-                                }
+        /* if the user specified that they didn't want anything printed (i.e. a -n
+         * flag and no 'p' flag after the s///), then there's really no point doing
+         * anything here. */
+        if (be_quiet && !sed_cmd->sub_p)
+                return 0;
 
-                                /* then print the substitution in its place */
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                                if(!be_quiet || (sed_cmd->sub_flags & SUB_P))
-#endif
-                                print_subst_w_backrefs(ptr, sed_cmd->replace, regmatch);
+        /* we only proceed if the substitution 'search' expression matches */
+        if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == REG_NOMATCH)
+                return 0;
 
-                                /* then advance past the match */
-                                ptr += regmatch[0].rm_eo;
+        /* whaddaya know, it matched. get the number of back references */
+        regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
 
-                                /* and flag that something has changed */
-                                altered++;
+        /* and now, as long as we've got a line to try matching and if we can match
+         * the search string, we make substitutions */
+        while (*hackline && (regexec(sed_cmd->sub_match, hackline,
+                                        sed_cmd->num_backrefs+1, regmatch, 0) == 0) ) {
+                int i;
 
-                                /* if we're not doing this globally... */
-                                if (!sed_cmd->sub_flags & SUB_G)
-                                        break;
-                        }
-                        /* if we COULD NOT match the search string (meaning we've gone past
-                         * all previous instances), get out */
-                        else
-                                break;
-                }
+                /* print everything before the match */
+                for (i = 0; i < regmatch[0].rm_so; i++)
+                        fputc(hackline[i], stdout);
 
-                /* is there anything left to print? */
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                if (*ptr && (!be_quiet || sed_cmds->sub_flags & SUB_P))
-#else
-                if (*ptr) 
-#endif
-                        fputs(ptr, stdout);
+                /* then print the substitution string */
+                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
+
+                /* advance past the match */
+                hackline += regmatch[0].rm_eo;
+                /* flag that something has changed */
+                altered++;
 
-                /* cleanup */
-                free(regmatch);
+                /* if we're not doing this globally, get out now */
+                if (!sed_cmd->sub_g)
+                        break;
         }
 
+        /* if there's anything left of the line, print it */
+        if (*hackline)
+                fputs(hackline, stdout);
+
+        /* cleanup */
+        free(regmatch);
+
         return altered;
 }
 
@@ -605,7 +598,32 @@ static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
                         break;
 
                 case 's':
-                        altered = do_subst_command(sed_cmd, line);
+
+                        /*
+                         * Some special cases for 's' printing to make it compliant with
+                         * GNU sed printing behavior (aka "The -n | s///p Matrix"):
+                         *
+                         *    -n ONLY = never print anything regardless of any successful
+                         *    substitution
+                         *
+                         *    s///p ONLY = always print successful substitutions, even if
+                         *    the line is going to be printed anyway (line will be printed
+                         *    twice).
+                         *
+                         *    -n AND s///p = print ONLY a successful substitution ONE TIME;
+                         *    no other lines are printed - this is the reason why the 'p'
+                         *    flag exists in the first place.
+                         */
+
+                        /* we print the line once, unless we were told to be quiet */
+                        if (!be_quiet)
+                                altered = do_subst_command(sed_cmd, line);
+
+                        /* we also print the line if we were given the 'p' flag
+                         * (this is quite possibly the second printing) */
+                        if (sed_cmd->sub_p)
+                                altered = do_subst_command(sed_cmd, line);
+
                         break;
 
                 case 'a':
@@ -662,7 +680,8 @@ static void process_file(FILE *file)
 
                         /* are we acting on a range of line numbers? */
                         else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line != 0) {
-                                if (linenum >= sed_cmds[i].beg_line && (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
+                                if (linenum >= sed_cmds[i].beg_line &&
+                                                (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
                                         line_altered += do_sed_command(&sed_cmds[i], line);
                         }
 
@@ -678,14 +697,10 @@ static void process_file(FILE *file)
 
                 }
 
-                /* we will print the line unless we were told to be quiet or if
-                 * the line was altered (via a 'd'elete or 's'ubstitution) */
-#ifndef BB_FEATURE_SED_PATTERN_SPACE
-                if (!be_quiet &&!line_altered)
-#else
-                /*  we where specificly requested to print the output */
-                if ((!be_quiet || (sed_cmds[i].sub_flags & SUB_P)) && !line_altered)
-#endif
+                /* we will print the line unless we were told to be quiet or if the
+                 * line was altered (via a 'd'elete or 's'ubstitution), in which case
+                 * the altered line was already printed */
+                if (!be_quiet && !line_altered)
                         fputs(line, stdout);
 
                 free(line);
diff --git a/sed.c b/sed.c
index 75435f67a..eaca9ada5 100644
--- a/sed.c
+++ b/sed.c
@@ -62,13 +62,12 @@ extern char *optarg; /* ditto */
 /* options */
 static int be_quiet = 0;
 
-static const int SUB_G = 1 << 0;
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-static const int SUB_P = 1 << 1;
-#endif
 
 struct sed_cmd {
 
+
+        /* GENERAL FIELDS */
+
         /* address storage */
         int beg_line; /* 'sed 1p'   0 == no begining line, apply commands to all lines */
         int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
@@ -78,19 +77,21 @@ struct sed_cmd {
         /* the command */
         char cmd; /* p,d,s (add more at your leisure :-) */
 
-        /* substitution command specific fields */
-        regex_t *sub_match; /* sed -e 's/sub_match/replace/' */
-        char *replace; /* sed -e 's/sub_match/replace/' XXX: who will hold the \1 \2 \3s? */
+
+        /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
+
+        /* sed -e 's/sub_match/replace/' */
+        regex_t *sub_match;
+        char *replace;
         unsigned int num_backrefs:4; /* how many back references (\1..\9) */
                         /* Note:  GNU/POSIX sed does not save more than nine backrefs, so
                          * we only use 4 bits to hold the number */
-#ifndef BB_FEATURE_SED_PATTERN_SPACE
-        unsigned int sub_flags:1; /* sed -e 's/foo/bar/g' (global) */
-#else
-        unsigned int sub_flags:2; /* sed -e 's/foo/bar/gp' (global/pattern) */
-#endif
+        unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
+        unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
+
+
+        /* EDIT COMMAND (a,i,c) SPEICIFIC FIELDS */
 
-        /* edit command (a,i,c) speicific field */
         char *editline;
 };
 
@@ -278,7 +279,7 @@ static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
         /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */ 
         for (j = 0; match[j]; j++) {
                 /* GNU/POSIX sed does not save more than nine backrefs */
-                if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs < 9)
+                if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
                         sed_cmd->num_backrefs++;
         }
 
@@ -293,16 +294,14 @@ static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
         while (substr[++idx]) {
                 switch (substr[idx]) {
                         case 'g':
-                                sed_cmd->sub_flags = SUB_G;
+                                sed_cmd->sub_g = 1;
                                 break;
                         case 'I':
                                 cflags |= REG_ICASE;
                                 break;
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
                         case 'p':
-                                sed_cmd->sub_flags = SUB_P;
+                                sed_cmd->sub_p = 1;
                                 break;
-#endif
                         default:
                                 /* any whitespace or semicolon trailing after a s/// is ok */
                                 if (strchr("; \t\v\n\r", substr[idx]))
@@ -534,59 +533,53 @@ static void print_subst_w_backrefs(const char *line, const char *replace, regmat
 
 static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
 {
+        char *hackline = (char *)line;
         int altered = 0;
+        regmatch_t *regmatch = NULL;
 
-        /* we only substitute if the substitution 'search' expression matches */
-        if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == 0) {
-                regmatch_t *regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
-                int i;
-                char *ptr = (char *)line;
-
-                while (*ptr) {
-                        /* if we can match the search string... */
-                        if (regexec(sed_cmd->sub_match, ptr, sed_cmd->num_backrefs+1, regmatch, 0) == 0) {
-                                /* print everything before the match, */
-                                for (i = 0; i < regmatch[0].rm_so; i++) {
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                                        if(!be_quiet || (sed_cmd->sub_flags & SUB_P))
-#endif
-                                        fputc(ptr[i], stdout);
-                                }
+        /* if the user specified that they didn't want anything printed (i.e. a -n
+         * flag and no 'p' flag after the s///), then there's really no point doing
+         * anything here. */
+        if (be_quiet && !sed_cmd->sub_p)
+                return 0;
 
-                                /* then print the substitution in its place */
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                                if(!be_quiet || (sed_cmd->sub_flags & SUB_P))
-#endif
-                                print_subst_w_backrefs(ptr, sed_cmd->replace, regmatch);
+        /* we only proceed if the substitution 'search' expression matches */
+        if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == REG_NOMATCH)
+                return 0;
 
-                                /* then advance past the match */
-                                ptr += regmatch[0].rm_eo;
+        /* whaddaya know, it matched. get the number of back references */
+        regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
 
-                                /* and flag that something has changed */
-                                altered++;
+        /* and now, as long as we've got a line to try matching and if we can match
+         * the search string, we make substitutions */
+        while (*hackline && (regexec(sed_cmd->sub_match, hackline,
+                                        sed_cmd->num_backrefs+1, regmatch, 0) == 0) ) {
+                int i;
 
-                                /* if we're not doing this globally... */
-                                if (!sed_cmd->sub_flags & SUB_G)
-                                        break;
-                        }
-                        /* if we COULD NOT match the search string (meaning we've gone past
-                         * all previous instances), get out */
-                        else
-                                break;
-                }
+                /* print everything before the match */
+                for (i = 0; i < regmatch[0].rm_so; i++)
+                        fputc(hackline[i], stdout);
 
-                /* is there anything left to print? */
-#ifdef BB_FEATURE_SED_PATTERN_SPACE
-                if (*ptr && (!be_quiet || sed_cmds->sub_flags & SUB_P))
-#else
-                if (*ptr) 
-#endif
-                        fputs(ptr, stdout);
+                /* then print the substitution string */
+                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
+
+                /* advance past the match */
+                hackline += regmatch[0].rm_eo;
+                /* flag that something has changed */
+                altered++;
 
-                /* cleanup */
-                free(regmatch);
+                /* if we're not doing this globally, get out now */
+                if (!sed_cmd->sub_g)
+                        break;
         }
 
+        /* if there's anything left of the line, print it */
+        if (*hackline)
+                fputs(hackline, stdout);
+
+        /* cleanup */
+        free(regmatch);
+
         return altered;
 }
 
@@ -605,7 +598,32 @@ static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
                         break;
 
                 case 's':
-                        altered = do_subst_command(sed_cmd, line);
+
+                        /*
+                         * Some special cases for 's' printing to make it compliant with
+                         * GNU sed printing behavior (aka "The -n | s///p Matrix"):
+                         *
+                         *    -n ONLY = never print anything regardless of any successful
+                         *    substitution
+                         *
+                         *    s///p ONLY = always print successful substitutions, even if
+                         *    the line is going to be printed anyway (line will be printed
+                         *    twice).
+                         *
+                         *    -n AND s///p = print ONLY a successful substitution ONE TIME;
+                         *    no other lines are printed - this is the reason why the 'p'
+                         *    flag exists in the first place.
+                         */
+
+                        /* we print the line once, unless we were told to be quiet */
+                        if (!be_quiet)
+                                altered = do_subst_command(sed_cmd, line);
+
+                        /* we also print the line if we were given the 'p' flag
+                         * (this is quite possibly the second printing) */
+                        if (sed_cmd->sub_p)
+                                altered = do_subst_command(sed_cmd, line);
+
                         break;
 
                 case 'a':
@@ -662,7 +680,8 @@ static void process_file(FILE *file)
 
                         /* are we acting on a range of line numbers? */
                         else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line != 0) {
-                                if (linenum >= sed_cmds[i].beg_line && (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
+                                if (linenum >= sed_cmds[i].beg_line &&
+                                                (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
                                         line_altered += do_sed_command(&sed_cmds[i], line);
                         }
 
@@ -678,14 +697,10 @@ static void process_file(FILE *file)
 
                 }
 
-                /* we will print the line unless we were told to be quiet or if
-                 * the line was altered (via a 'd'elete or 's'ubstitution) */
-#ifndef BB_FEATURE_SED_PATTERN_SPACE
-                if (!be_quiet &&!line_altered)
-#else
-                /*  we where specificly requested to print the output */
-                if ((!be_quiet || (sed_cmds[i].sub_flags & SUB_P)) && !line_altered)
-#endif
+                /* we will print the line unless we were told to be quiet or if the
+                 * line was altered (via a 'd'elete or 's'ubstitution), in which case
+                 * the altered line was already printed */
+                if (!be_quiet && !line_altered)
                         fputs(line, stdout);
 
                 free(line);