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authorDenis Vlasenko2007-01-17 23:16:16 +0000
committerDenis Vlasenko2007-01-17 23:16:16 +0000
commitef44d9d9f2aa5d0333d5a7a2749e32c6be94365d (patch)
tree037c0440778c656210c64f32dcfa69e27df1cda9 /editors/sed.c
parentae114c235e2bf2987fceb6065b57dee93740c593 (diff)
downloadbusybox-ef44d9d9f2aa5d0333d5a7a2749e32c6be94365d.zip
busybox-ef44d9d9f2aa5d0333d5a7a2749e32c6be94365d.tar.gz
sed,get_line_from_file: improve comments
Diffstat (limited to 'editors/sed.c')
-rw-r--r--editors/sed.c44
1 files changed, 27 insertions, 17 deletions
diff --git a/editors/sed.c b/editors/sed.c
index 23d73fa..674381b 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -576,28 +576,33 @@ static void do_subst_w_backrefs(char *line, char *replace)
/* go through the replacement string */
for (i = 0; replace[i]; i++) {
/* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
- if (replace[i] == '\\' && replace[i+1] >= '0' && replace[i+1] <= '9') {
- int backref = replace[++i]-'0';
-
- /* print out the text held in bbg.regmatch[backref] */
- if (bbg.regmatch[backref].rm_so != -1) {
- j = bbg.regmatch[backref].rm_so;
- while (j < bbg.regmatch[backref].rm_eo)
- pipe_putc(line[j++]);
+ if (replace[i] == '\\') {
+ unsigned backref = replace[++i] - '0';
+ if (backref <= 9) {
+ /* print out the text held in bbg.regmatch[backref] */
+ if (bbg.regmatch[backref].rm_so != -1) {
+ j = bbg.regmatch[backref].rm_so;
+ while (j < bbg.regmatch[backref].rm_eo)
+ pipe_putc(line[j++]);
+ }
+ continue;
}
+ /* I _think_ it is impossible to get '\' to be
+ * the last char in replace string. Thus we dont check
+ * for replace[i] == NUL. (counterexample anyone?) */
+ /* if we find a backslash escaped character, print the character */
+ pipe_putc(replace[i]);
+ continue;
}
-
- /* if we find a backslash escaped character, print the character */
- else if (replace[i] == '\\') pipe_putc(replace[++i]);
-
/* if we find an unescaped '&' print out the whole matched text. */
- else if (replace[i] == '&') {
+ if (replace[i] == '&') {
j = bbg.regmatch[0].rm_so;
while (j < bbg.regmatch[0].rm_eo)
pipe_putc(line[j++]);
+ continue;
}
/* Otherwise just output the character. */
- else pipe_putc(replace[i]);
+ pipe_putc(replace[i]);
}
}
@@ -722,6 +727,9 @@ static char *get_next_line(int *last_char)
lc = 0;
flush_append();
while (bbg.current_input_file < bbg.input_file_count) {
+ /* Read line up to a newline or NUL byte, inclusive,
+ * return malloc'ed char[]. length of the chunk read
+ * is stored in len. NULL if EOF/error */
temp = bb_get_chunk_from_file(
bbg.input_file_list[bbg.current_input_file], &len);
if (temp) {
@@ -753,7 +761,8 @@ static char *get_next_line(int *last_char)
* echo -n thingy >z1
* echo -n again >z2
* >znull
- * sed "s/i/z/" z1 z2 znull | hexdump -vC output:
+ * sed "s/i/z/" z1 z2 znull | hexdump -vC
+ * output:
* gnu sed 4.1.5:
* 00000000 74 68 7a 6e 67 79 0a 61 67 61 7a 6e |thzngy.agazn|
* bbox:
@@ -771,8 +780,9 @@ static int puts_maybe_newline(char *s, FILE *file, int prev_last_char, int last_
last_puts_char = '\n';
}
fputs(s, file);
- /* 'x': we don't care what is it, but we know it isn't '\n' */
- if (s[0]) last_puts_char = 'x';
+ /* why 'x'? - just something which is not '\n' */
+ if (s[0])
+ last_puts_char = 'x';
if (!(last_char & 0x100)) { /* had trailing '\n' or '\0'? */
last_char &= 0xff;
fputc(last_char, file);