[FFmpeg-devel] [PATCH] lavu: add escape API
Stefano Sabatini
stefasab at gmail.com
Sun Dec 16 12:35:52 CET 2012
The escape API will be useful to perform escaping programmatically, which
is required when crafting argument strings, and will be used for context
printing as well.
TODO: bump minor, add APIchanges entry
---
libavutil/avstring.c | 18 ++++++++++++
libavutil/avstring.h | 19 +++++++++++++
libavutil/bprint.c | 49 +++++++++++++++++++++++++++++++++
libavutil/bprint.h | 14 ++++++++++
tools/ffescape.c | 75 ++++----------------------------------------------
5 files changed, 105 insertions(+), 70 deletions(-)
diff --git a/libavutil/avstring.c b/libavutil/avstring.c
index f03df67..b2af333 100644
--- a/libavutil/avstring.c
+++ b/libavutil/avstring.c
@@ -26,6 +26,7 @@
#include <ctype.h>
#include "avstring.h"
#include "mem.h"
+#include "bprint.h"
int av_strstart(const char *str, const char *pfx, const char **ptr)
{
@@ -211,6 +212,23 @@ int av_strncasecmp(const char *a, const char *b, size_t n)
return c1 - c2;
}
+int av_escape(char **dst, const char *src, const char *special_chars,
+ enum AVEscapeMode mode)
+{
+ AVBPrint dstbuf;
+
+ av_bprint_init(&dstbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
+
+ av_bprint_escape(&dstbuf, src, special_chars, mode);
+ if (!av_bprint_is_complete(&dstbuf)) {
+ av_bprint_finalize(&dstbuf, NULL);
+ return AVERROR(ENOMEM);
+ } else {
+ av_bprint_finalize(&dstbuf, dst);
+ return 0;
+ }
+}
+
#ifdef TEST
#include "common.h"
diff --git a/libavutil/avstring.h b/libavutil/avstring.h
index f73d6e7..0940e2b 100644
--- a/libavutil/avstring.h
+++ b/libavutil/avstring.h
@@ -202,6 +202,25 @@ int av_strcasecmp(const char *a, const char *b);
*/
int av_strncasecmp(const char *a, const char *b, size_t n);
+enum AVEscapeMode {
+ AV_ESCAPE_MODE_FULL, ///< escape each single special character and whitespace by prefixing '\'
+ AV_ESCAPE_MODE_LAZY, ///< as AV_ESCAPE_MODE_FULL, but only escape whitespaces at the begin and at the end of the string
+ AV_ESCAPE_MODE_QUOTE, ///< perform quote-escaping
+};
+
+#define AV_WHITESPACES " \n\t"
+
+/**
+ * Escape string in src, and put the escaped string in an allocated
+ * string in *dst, which must be freed with av_free().
+ *
+ * @param special_chars string containing the special characters which need to be escaped
+ * @param mode escape mode to employ
+ * @return >=0 in case of success, or a negative error code in case of error
+ */
+int av_escape(char **dst, const char *src, const char *special_chars,
+ enum AVEscapeMode mode);
+
/**
* @}
*/
diff --git a/libavutil/bprint.c b/libavutil/bprint.c
index 4684ab4..6ea1e3e 100644
--- a/libavutil/bprint.c
+++ b/libavutil/bprint.c
@@ -23,6 +23,7 @@
#include <string.h>
#include <time.h>
#include "avassert.h"
+#include "avstring.h"
#include "bprint.h"
#include "common.h"
#include "error.h"
@@ -217,6 +218,54 @@ int av_bprint_finalize(AVBPrint *buf, char **ret_str)
return ret;
}
+int av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
+ enum AVEscapeMode mode)
+{
+ switch (mode) {
+ case AV_ESCAPE_MODE_FULL:
+ case AV_ESCAPE_MODE_LAZY:
+ /* \-escape characters */
+
+ if (mode == AV_ESCAPE_MODE_LAZY && strchr(AV_WHITESPACES, *src))
+ av_bprintf(dstbuf, "\\%c", *src++);
+
+ for (; *src; src++) {
+ if ((special_chars && strchr(special_chars, *src)) ||
+ strchr("'\\", *src) ||
+ (mode == AV_ESCAPE_MODE_FULL && strchr(AV_WHITESPACES, *src)))
+ av_bprintf(dstbuf, "\\%c", *src);
+ else
+ av_bprint_chars(dstbuf, *src, 1);
+ }
+
+ if (mode == AV_ESCAPE_MODE_LAZY &&
+ strchr(AV_WHITESPACES, dstbuf->str[dstbuf->len-1])) {
+ char c = dstbuf->str[dstbuf->len-1];
+ dstbuf->str[dstbuf->len-1] = '\\';
+ av_bprint_chars(dstbuf, c, 1);
+ }
+ break;
+
+ case AV_ESCAPE_MODE_QUOTE:
+ /* enclose between '' the string */
+ av_bprint_chars(dstbuf, '\'', 1);
+ for (; *src; src++) {
+ if (*src == '\'')
+ av_bprintf(dstbuf, "'\\''");
+ else
+ av_bprint_chars(dstbuf, *src, 1);
+ }
+ av_bprint_chars(dstbuf, '\'', 1);
+ break;
+
+ default:
+ /* unknown escape mode */
+ return AVERROR(EINVAL);
+ }
+
+ return 0;
+}
+
#ifdef TEST
#undef printf
diff --git a/libavutil/bprint.h b/libavutil/bprint.h
index f3915fe..3506d7c 100644
--- a/libavutil/bprint.h
+++ b/libavutil/bprint.h
@@ -22,6 +22,7 @@
#define AVUTIL_BPRINT_H
#include "attributes.h"
+#include "avstring.h"
/**
* Define a structure with extra padding to a fixed size
@@ -180,4 +181,17 @@ static inline int av_bprint_is_complete(AVBPrint *buf)
*/
int av_bprint_finalize(AVBPrint *buf, char **ret_str);
+/**
+ * Escape the content in src and append it to dstbuf.
+ *
+ * @param dstbuf already inited destination bprint buffer
+ * @param src string containing the text to escape
+ * @param special_chars list of special characters to escape
+ * @param mode escape mode to employ
+ * @return >= 0 in case of success, a negative value in case of error
+ * @see av_escape()
+ */
+int av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
+ enum AVEscapeMode mode);
+
#endif /* AVUTIL_BPRINT_H */
diff --git a/tools/ffescape.c b/tools/ffescape.c
index d777fe4..6291547 100644
--- a/tools/ffescape.c
+++ b/tools/ffescape.c
@@ -51,71 +51,6 @@ static void usage(void)
"-s SPECIAL_CHARS set the list of special characters\n");
}
-#define WHITESPACES " \n\t"
-
-enum EscapeMode {
- ESCAPE_MODE_FULL,
- ESCAPE_MODE_LAZY,
- ESCAPE_MODE_QUOTE,
-};
-
-static int escape(char **dst, const char *src, const char *special_chars,
- enum EscapeMode mode)
-{
- AVBPrint dstbuf;
-
- av_bprint_init(&dstbuf, 1, AV_BPRINT_SIZE_UNLIMITED);
-
- switch (mode) {
- case ESCAPE_MODE_FULL:
- case ESCAPE_MODE_LAZY:
- /* \-escape characters */
-
- if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, *src))
- av_bprintf(&dstbuf, "\\%c", *src++);
-
- for (; *src; src++) {
- if ((special_chars && strchr(special_chars, *src)) ||
- strchr("'\\", *src) ||
- (mode == ESCAPE_MODE_FULL && strchr(WHITESPACES, *src)))
- av_bprintf(&dstbuf, "\\%c", *src);
- else
- av_bprint_chars(&dstbuf, *src, 1);
- }
-
- if (mode == ESCAPE_MODE_LAZY && strchr(WHITESPACES, dstbuf.str[dstbuf.len-1])) {
- char c = dstbuf.str[dstbuf.len-1];
- dstbuf.str[dstbuf.len-1] = '\\';
- av_bprint_chars(&dstbuf, c, 1);
- }
- break;
-
- case ESCAPE_MODE_QUOTE:
- /* enclose between '' the string */
- av_bprint_chars(&dstbuf, '\'', 1);
- for (; *src; src++) {
- if (*src == '\'')
- av_bprintf(&dstbuf, "'\\''");
- else
- av_bprint_chars(&dstbuf, *src, 1);
- }
- av_bprint_chars(&dstbuf, '\'', 1);
- break;
-
- default:
- /* unknown escape mode */
- return AVERROR(EINVAL);
- }
-
- if (!av_bprint_is_complete(&dstbuf)) {
- av_bprint_finalize(&dstbuf, NULL);
- return AVERROR(ENOMEM);
- } else {
- av_bprint_finalize(&dstbuf, dst);
- return 0;
- }
-}
-
int main(int argc, char **argv)
{
AVBPrint src;
@@ -123,7 +58,7 @@ int main(int argc, char **argv)
const char *outfilename = NULL, *infilename = NULL;
FILE *outfile = NULL, *infile = NULL;
const char *prompt = "=> ";
- enum EscapeMode escape_mode = ESCAPE_MODE_LAZY;
+ enum AVEscapeMode escape_mode = AV_ESCAPE_MODE_LAZY;
int level = 1;
int echo = 0;
char *special_chars = NULL;
@@ -154,9 +89,9 @@ int main(int argc, char **argv)
break;
}
case 'm':
- if (!strcmp(optarg, "full")) escape_mode = ESCAPE_MODE_FULL;
- else if (!strcmp(optarg, "lazy")) escape_mode = ESCAPE_MODE_LAZY;
- else if (!strcmp(optarg, "quote")) escape_mode = ESCAPE_MODE_QUOTE;
+ if (!strcmp(optarg, "full")) escape_mode = AV_ESCAPE_MODE_FULL;
+ else if (!strcmp(optarg, "lazy")) escape_mode = AV_ESCAPE_MODE_LAZY;
+ else if (!strcmp(optarg, "quote")) escape_mode = AV_ESCAPE_MODE_QUOTE;
else {
av_log(NULL, AV_LOG_ERROR,
"Invalid value '%s' for option -m, "
@@ -219,7 +154,7 @@ int main(int argc, char **argv)
/* escape */
dst_buf = src_buf;
while (level--) {
- if (escape(&dst_buf, src_buf, special_chars, escape_mode) < 0) {
+ if (av_escape(&dst_buf, src_buf, special_chars, escape_mode) < 0) {
av_log(NULL, AV_LOG_ERROR, "Could not escape string\n");
return 1;
}
--
1.7.9.5
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