The most common use of addf() was to init a strbuf and addf() right away.
Since it is so common, it makes sense to have a function strbuf_initf() to
wrap both calls into one.
To do that, we implement a (really minimal) vaddf() lookalike to
vsprintf().
At the moment, it only handles %u, %i, %d, %l, %o, %x and %X with size
indicators '<number>', ' <number>' and '0<number>', as well as %c and %s,
the latter with size indicators '.*' in addition to the same size
indicators as for numbers.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
On Thu, 6 Mar 2008, Johannes Schindelin wrote:
> Of course, having a simple implementation for addf() _not_ using
> vsnprintf() could help, too (and make the process more efficient,
> probably).
Having thought about this a bit, I came up with this
implementation (replacing my earlier PATCH 1/2). It is by far not
complete, but that is exactly the idea: we do not _need_ a fully-fledged
printf() implementation.
Besides, it was fun.
.gitignore | 1 +
Makefile | 4 +-
strbuf.c | 134 +++++++++++++++++++++++++++++++++++++++++++++++------
strbuf.h | 3 +
t/t0000-basic.sh | 8 +++
test-strbuf.c | 17 +++++++
6 files changed, 150 insertions(+), 17 deletions(-)
create mode 100644 test-strbuf.c
diff --git a/.gitignore b/.gitignore
index 219759f..c0ecd41 100644
--- a/.gitignore
+++ b/.gitignore
@@ -152,6 +152,7 @@ test-genrandom
test-match-trees
test-parse-options
test-sha1
+test-strbuf
common-cmds.h
*.tar.gz
*.dsc
diff --git a/Makefile b/Makefile
index cd0b294..58f6238 100644
--- a/Makefile
+++ b/Makefile
@@ -1052,7 +1052,7 @@ endif
### Testing rules
-TEST_PROGRAMS = test-chmtime$X test-genrandom$X test-date$X test-delta$X test-sha1$X test-match-trees$X test-absolute-path$X test-parse-options$X
+TEST_PROGRAMS = test-chmtime$X test-genrandom$X test-date$X test-delta$X test-sha1$X test-match-trees$X test-absolute-path$X test-parse-options$X test-strbuf$X
all:: $(TEST_PROGRAMS)
@@ -1071,6 +1071,8 @@ test-delta$X: diff-delta.o patch-delta.o
test-parse-options$X: parse-options.o
+test-strbuf$X: strbuf.o
+
.PRECIOUS: $(patsubst test-%$X,test-%.o,$(TEST_PROGRAMS))
test-%$X: test-%.o $(GITLIBS)
diff --git a/strbuf.c b/strbuf.c
index 5afa8f3..5ad89a8 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -123,28 +123,130 @@ void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
strbuf_setlen(sb, sb->len + len);
}
+static int number_length(unsigned long number, long base)
+{
+ int length = 1;
+ while (number >= base) {
+ number /= base;
+ length++;
+ }
+ return length;
+}
+
+/*
+ * Only supports %u, %i, %d, %l, %o, %x and %X with size indicators
+ * '<number>', '0<number>', and ' <number>',
+ * as well as %c,
+ * and %s with size indicators '<number>', ' <number>' and '.*'.
+ */
+void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
+{
+ while (*fmt) {
+ char fill = '\0';
+ int size = -1, max_size = -1;
+ char *p = (char *)fmt;
+
+ if (*p != '%' || *(++p) == '%') {
+ strbuf_addch(sb, *p++);
+ fmt = p;
+ continue;
+ }
+ if (*p == ' ' || *p == '0')
+ fill = *p++;
+ if (isdigit(*p))
+ size = (int)strtol(p, &p, 10);
+ else if (!prefixcmp(p, ".*")) {
+ max_size = va_arg(ap, int);
+ p += 2;
+ }
+ switch (*p) {
+ case 's': {
+ const char *s = va_arg(ap, const char *);
+ if (fill) {
+ int len = size - strlen(s);
+ while (len-- > 0)
+ strbuf_addch(sb, fill);
+ }
+ while (*s && max_size--)
+ strbuf_addch(sb, *s++);
+ break;
+ }
+ case 'c':
+ strbuf_addch(sb, va_arg(ap, int));
+ break;
+ case 'u':
+ case 'i':
+ case 'l':
+ case 'd':
+ case 'o':
+ case 'x':
+ case 'X': {
+ int base = *p == 'x' || *p == 'X' ? 16 :
+ *p == 'o' ? 8 : 10;
+ int negative = 0, len;
+ unsigned long number, power;
+
+ if (*p == 'u')
+ number = va_arg(ap, unsigned int);
+ else {
+ long signed_number;
+ if (*p == 'l')
+ signed_number = va_arg(ap, long);
+ else
+ signed_number = va_arg(ap, int);
+ if (signed_number < 0) {
+ negative = 1;
+ number = -signed_number;
+ } else
+ number = signed_number;
+ }
+
+ /* pad */
+ len = number_length(number, base);
+ while (size-- > len + negative)
+ strbuf_addch(sb, fill ? fill : ' ');
+ if (negative)
+ strbuf_addch(sb, '-');
+
+ /* output number */
+ power = 1;
+ while (len-- > 1)
+ power *= base;
+ while (power) {
+ int digit = number / power;
+ strbuf_addch(sb, digit < 10 ? '0' + digit
+ : *p + 'A' - 'X' + digit - 10);
+ number -= digit * power;
+ power /= base;
+ }
+
+ break;
+ }
+ default:
+ /* unknown / invalid format: copy verbatim */
+ strbuf_insert(sb, sb->len, fmt, p - fmt + 1);
+ }
+ fmt = p + (*p != '\0');
+ }
+}
+
void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
- int len;
va_list ap;
- if (!strbuf_avail(sb))
- strbuf_grow(sb, 64);
va_start(ap, fmt);
- len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+ strbuf_vaddf(sb, fmt, ap);
+ va_end(ap);
+}
+
+void strbuf_initf(struct strbuf *sb, const char *fmt, ...)
+{
+ va_list ap;
+
+ strbuf_init(sb, strlen(fmt) + 64);
+ va_start(ap, fmt);
+ strbuf_vaddf(sb, fmt, ap);
va_end(ap);
- if (len < 0)
- die("your vsnprintf is broken");
- if (len > strbuf_avail(sb)) {
- strbuf_grow(sb, len);
- va_start(ap, fmt);
- len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
- va_end(ap);
- if (len > strbuf_avail(sb)) {
- die("this should not happen, your snprintf is broken");
- }
- }
- strbuf_setlen(sb, sb->len + len);
}
void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
diff --git a/strbuf.h b/strbuf.h
index faec229..d7c7aaf 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -106,8 +106,11 @@ extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
+extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list args);
__attribute__((format(printf,2,3)))
extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
+__attribute__((format(printf,2,3)))
+extern void strbuf_initf(struct strbuf *sb, const char *fmt, ...);
extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
/* XXX: if read fails, any partial read is undone */
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 27b54cb..c1d4639 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -311,6 +311,14 @@ test_expect_success 'absolute path works as expected' '
test "$sym" = "$(test-absolute-path $dir2/syml)"
'
+test_expect_success 'strbuf_initf() works as expected' '
+
+ eval $(test-strbuf) &&
+ test ! -z "$result" &&
+ test "$result" = "$expect"
+
+'
+
test_expect_success 'very long name in the index handled sanely' '
a=a && # 1
diff --git a/test-strbuf.c b/test-strbuf.c
new file mode 100644
index 0000000..479fa08
--- /dev/null
+++ b/test-strbuf.c
@@ -0,0 +1,17 @@
+#include "cache.h"
+#include "strbuf.h"
+
+int main(int argc, char **argv)
+{
+ struct strbuf buf;
+#define TEST_FORMAT \
+ "'%%%.*s,%x,%05X,%u,%i,% 4d,%3d,%c,%3d'", \
+ 5, "Hello, World!", 27, 27, -1, -1, 1, 5, ':', 1234
+
+ strbuf_initf(&buf, TEST_FORMAT);
+ printf("result=%s\n", buf.buf);
+ printf("expect=" TEST_FORMAT);
+ strbuf_release(&buf);
+
+ return 0;
+}
--
1.5.4.3.571.g9aec3.dirty
--
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