avcodec/srtdec: factor out HTML parsing code

This code will be used in SAMI decoder in a later commit.

Signed-off-by: Clément Bœsch <u@pkh.me>

4 files changed, 208 insertions, 148 deletions

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 893fc96d84..4f6a52cceb 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -473,7 +473,7 @@ OBJS-$(CONFIG_SONIC_DECODER)           += sonic.o
 OBJS-$(CONFIG_SONIC_ENCODER)           += sonic.o
 OBJS-$(CONFIG_SONIC_LS_ENCODER)        += sonic.o
 OBJS-$(CONFIG_SP5X_DECODER)            += sp5xdec.o
-OBJS-$(CONFIG_SRT_DECODER)             += srtdec.o ass.o
+OBJS-$(CONFIG_SRT_DECODER)             += srtdec.o ass.o htmlsubtitles.o
 OBJS-$(CONFIG_SRT_ENCODER)             += srtenc.o ass_split.o
 OBJS-$(CONFIG_STL_DECODER)             += textdec.o ass.o
 OBJS-$(CONFIG_SUBRIP_DECODER)          += srtdec.o ass.o
diff --git a/libavcodec/htmlsubtitles.c b/libavcodec/htmlsubtitles.c
new file mode 100644
index 0000000000..97be82daa0
--- /dev/null
+++ b/libavcodec/htmlsubtitles.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avstring.h"
+#include "libavutil/common.h"
+#include "libavutil/parseutils.h"
+#include "avcodec.h"
+#include "htmlsubtitles.h"
+
+static int html_color_parse(AVCodecContext *avctx, const char *str)
+{
+    uint8_t rgba[4];
+    if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
+        return -1;
+    return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
+}
+
+enum {
+    PARAM_UNKNOWN = -1,
+    PARAM_SIZE,
+    PARAM_COLOR,
+    PARAM_FACE,
+    PARAM_NUMBER
+};
+
+typedef struct SrtStack {
+    char tag[128];
+    char param[PARAM_NUMBER][128];
+} SrtStack;
+
+static void rstrip_spaces_buf(AVBPrint *buf)
+{
+    while (buf->len > 0 && buf->str[buf->len - 1] == ' ')
+        buf->str[--buf->len] = 0;
+}
+
+void ff_htmlmarkup_to_ass(AVCodecContext *avctx, AVBPrint *dst, const char *in)
+{
+    char *param, buffer[128], tmp[128];
+    int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
+    SrtStack stack[16];
+
+    stack[0].tag[0] = 0;
+    strcpy(stack[0].param[PARAM_SIZE],  "{\\fs}");
+    strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
+    strcpy(stack[0].param[PARAM_FACE],  "{\\fn}");
+
+    for (; !end && *in; in++) {
+        switch (*in) {
+        case '\r':
+            break;
+        case '\n':
+            if (line_start) {
+                end = 1;
+                break;
+            }
+            rstrip_spaces_buf(dst);
+            av_bprintf(dst, "\\N");
+            line_start = 1;
+            break;
+        case ' ':
+            if (!line_start)
+                av_bprint_chars(dst, *in, 1);
+            break;
+        case '{':    /* skip all {\xxx} substrings except for {\an%d}
+                        and all microdvd like styles such as {Y:xxx} */
+            len = 0;
+            an += sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0;
+            if ((an != 1 && (len = 0, sscanf(in, "{\\%*[^}]}%n", &len) >= 0 && len > 0)) ||
+                (len = 0, sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n", &len) >= 0 && len > 0)) {
+                in += len - 1;
+            } else
+                av_bprint_chars(dst, *in, 1);
+            break;
+        case '<':
+            tag_close = in[1] == '/';
+            len = 0;
+            if (sscanf(in+tag_close+1, "%127[^>]>%n", buffer, &len) >= 1 && len > 0) {
+                if ((param = strchr(buffer, ' ')))
+                    *param++ = 0;
+                if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
+                    ( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
+                    int i, j, unknown = 0;
+                    in += len + tag_close;
+                    if (!tag_close)
+                        memset(stack+sptr, 0, sizeof(*stack));
+                    if (!strcmp(buffer, "font")) {
+                        if (tag_close) {
+                            for (i=PARAM_NUMBER-1; i>=0; i--)
+                                if (stack[sptr-1].param[i][0])
+                                    for (j=sptr-2; j>=0; j--)
+                                        if (stack[j].param[i][0]) {
+                                            av_bprintf(dst, "%s", stack[j].param[i]);
+                                            break;
+                                        }
+                        } else {
+                            while (param) {
+                                if (!strncmp(param, "size=", 5)) {
+                                    unsigned font_size;
+                                    param += 5 + (param[5] == '"');
+                                    if (sscanf(param, "%u", &font_size) == 1) {
+                                        snprintf(stack[sptr].param[PARAM_SIZE],
+                                             sizeof(stack[0].param[PARAM_SIZE]),
+                                             "{\\fs%u}", font_size);
+                                    }
+                                } else if (!strncmp(param, "color=", 6)) {
+                                    param += 6 + (param[6] == '"');
+                                    snprintf(stack[sptr].param[PARAM_COLOR],
+                                         sizeof(stack[0].param[PARAM_COLOR]),
+                                         "{\\c&H%X&}",
+                                         html_color_parse(avctx, param));
+                                } else if (!strncmp(param, "face=", 5)) {
+                                    param += 5 + (param[5] == '"');
+                                    len = strcspn(param,
+                                                  param[-1] == '"' ? "\"" :" ");
+                                    av_strlcpy(tmp, param,
+                                               FFMIN(sizeof(tmp), len+1));
+                                    param += len;
+                                    snprintf(stack[sptr].param[PARAM_FACE],
+                                             sizeof(stack[0].param[PARAM_FACE]),
+                                             "{\\fn%s}", tmp);
+                                }
+                                if ((param = strchr(param, ' ')))
+                                    param++;
+                            }
+                            for (i=0; i<PARAM_NUMBER; i++)
+                                if (stack[sptr].param[i][0])
+                                    av_bprintf(dst, "%s", stack[sptr].param[i]);
+                        }
+                    } else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
+                        av_bprintf(dst, "{\\%c%d}", buffer[0], !tag_close);
+                    } else {
+                        unknown = 1;
+                        snprintf(tmp, sizeof(tmp), "</%s>", buffer);
+                    }
+                    if (tag_close) {
+                        sptr--;
+                    } else if (unknown && !strstr(in, tmp)) {
+                        in -= len + tag_close;
+                        av_bprint_chars(dst, *in, 1);
+                    } else
+                        av_strlcpy(stack[sptr++].tag, buffer,
+                                   sizeof(stack[0].tag));
+                    break;
+                }
+            }
+        default:
+            av_bprint_chars(dst, *in, 1);
+            break;
+        }
+        if (*in != ' ' && *in != '\r' && *in != '\n')
+            line_start = 0;
+    }
+
+    while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2))
+        dst->len -= 2;
+    dst->str[dst->len] = 0;
+    rstrip_spaces_buf(dst);
+}
diff --git a/libavcodec/htmlsubtitles.h b/libavcodec/htmlsubtitles.h
new file mode 100644
index 0000000000..b06a5af6c8
--- /dev/null
+++ b/libavcodec/htmlsubtitles.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_HTMLSUBTITLES_H
+#define AVCODEC_HTMLSUBTITLES_H
+
+#include "libavutil/bprint.h"
+
+void ff_htmlmarkup_to_ass(AVCodecContext *avctx, AVBPrint *dst, const char *in);
+
+
+#endif /* AVCODEC_HTMLSUBTITLES_H */
diff --git a/libavcodec/srtdec.c b/libavcodec/srtdec.c
index ed3af95063..dd6bc9d104 100644
--- a/libavcodec/srtdec.c
+++ b/libavcodec/srtdec.c
@@ -25,46 +25,11 @@
 #include "libavutil/parseutils.h"
 #include "avcodec.h"
 #include "ass.h"
-
-static int html_color_parse(AVCodecContext *avctx, const char *str)
-{
-    uint8_t rgba[4];
-    if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
-        return -1;
-    return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
-}
-
-enum {
-    PARAM_UNKNOWN = -1,
-    PARAM_SIZE,
-    PARAM_COLOR,
-    PARAM_FACE,
-    PARAM_NUMBER
-};
-
-typedef struct SrtStack {
-    char tag[128];
-    char param[PARAM_NUMBER][128];
-} SrtStack;
-
-static void rstrip_spaces_buf(AVBPrint *buf)
-{
-    while (buf->len > 0 && buf->str[buf->len - 1] == ' ')
-        buf->str[--buf->len] = 0;
-}
+#include "htmlsubtitles.h"
 
 static void srt_to_ass(AVCodecContext *avctx, AVBPrint *dst,
                        const char *in, int x1, int y1, int x2, int y2)
 {
-    char *param, buffer[128], tmp[128];
-    int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
-    SrtStack stack[16];
-
-    stack[0].tag[0] = 0;
-    strcpy(stack[0].param[PARAM_SIZE],  "{\\fs}");
-    strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
-    strcpy(stack[0].param[PARAM_FACE],  "{\\fn}");
-
     if (x1 >= 0 && y1 >= 0) {
         /* XXX: here we rescale coordinate assuming they are in DVD resolution
          * (720x480) since we don't have anything better */
@@ -84,117 +49,7 @@ static void srt_to_ass(AVCodecContext *avctx, AVBPrint *dst,
         }
     }
 
-    for (; !end && *in; in++) {
-        switch (*in) {
-        case '\r':
-            break;
-        case '\n':
-            if (line_start) {
-                end = 1;
-                break;
-            }
-            rstrip_spaces_buf(dst);
-            av_bprintf(dst, "\\N");
-            line_start = 1;
-            break;
-        case ' ':
-            if (!line_start)
-                av_bprint_chars(dst, *in, 1);
-            break;
-        case '{':    /* skip all {\xxx} substrings except for {\an%d}
-                        and all microdvd like styles such as {Y:xxx} */
-            len = 0;
-            an += sscanf(in, "{\\an%*1u}%n", &len) >= 0 && len > 0;
-            if ((an != 1 && (len = 0, sscanf(in, "{\\%*[^}]}%n", &len) >= 0 && len > 0)) ||
-                (len = 0, sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n", &len) >= 0 && len > 0)) {
-                in += len - 1;
-            } else
-                av_bprint_chars(dst, *in, 1);
-            break;
-        case '<':
-            tag_close = in[1] == '/';
-            len = 0;
-            if (sscanf(in+tag_close+1, "%127[^>]>%n", buffer, &len) >= 1 && len > 0) {
-                if ((param = strchr(buffer, ' ')))
-                    *param++ = 0;
-                if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
-                    ( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
-                    int i, j, unknown = 0;
-                    in += len + tag_close;
-                    if (!tag_close)
-                        memset(stack+sptr, 0, sizeof(*stack));
-                    if (!strcmp(buffer, "font")) {
-                        if (tag_close) {
-                            for (i=PARAM_NUMBER-1; i>=0; i--)
-                                if (stack[sptr-1].param[i][0])
-                                    for (j=sptr-2; j>=0; j--)
-                                        if (stack[j].param[i][0]) {
-                                            av_bprintf(dst, "%s", stack[j].param[i]);
-                                            break;
-                                        }
-                        } else {
-                            while (param) {
-                                if (!strncmp(param, "size=", 5)) {
-                                    unsigned font_size;
-                                    param += 5 + (param[5] == '"');
-                                    if (sscanf(param, "%u", &font_size) == 1) {
-                                        snprintf(stack[sptr].param[PARAM_SIZE],
-                                             sizeof(stack[0].param[PARAM_SIZE]),
-                                             "{\\fs%u}", font_size);
-                                    }
-                                } else if (!strncmp(param, "color=", 6)) {
-                                    param += 6 + (param[6] == '"');
-                                    snprintf(stack[sptr].param[PARAM_COLOR],
-                                         sizeof(stack[0].param[PARAM_COLOR]),
-                                         "{\\c&H%X&}",
-                                         html_color_parse(avctx, param));
-                                } else if (!strncmp(param, "face=", 5)) {
-                                    param += 5 + (param[5] == '"');
-                                    len = strcspn(param,
-                                                  param[-1] == '"' ? "\"" :" ");
-                                    av_strlcpy(tmp, param,
-                                               FFMIN(sizeof(tmp), len+1));
-                                    param += len;
-                                    snprintf(stack[sptr].param[PARAM_FACE],
-                                             sizeof(stack[0].param[PARAM_FACE]),
-                                             "{\\fn%s}", tmp);
-                                }
-                                if ((param = strchr(param, ' ')))
-                                    param++;
-                            }
-                            for (i=0; i<PARAM_NUMBER; i++)
-                                if (stack[sptr].param[i][0])
-                                    av_bprintf(dst, "%s", stack[sptr].param[i]);
-                        }
-                    } else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
-                        av_bprintf(dst, "{\\%c%d}", buffer[0], !tag_close);
-                    } else {
-                        unknown = 1;
-                        snprintf(tmp, sizeof(tmp), "</%s>", buffer);
-                    }
-                    if (tag_close) {
-                        sptr--;
-                    } else if (unknown && !strstr(in, tmp)) {
-                        in -= len + tag_close;
-                        av_bprint_chars(dst, *in, 1);
-                    } else
-                        av_strlcpy(stack[sptr++].tag, buffer,
-                                   sizeof(stack[0].tag));
-                    break;
-                }
-            }
-        default:
-            av_bprint_chars(dst, *in, 1);
-            break;
-        }
-        if (*in != ' ' && *in != '\r' && *in != '\n')
-            line_start = 0;
-    }
-
-    while (dst->len >= 2 && !strncmp(&dst->str[dst->len - 2], "\\N", 2))
-        dst->len -= 2;
-    dst->str[dst->len] = 0;
-    rstrip_spaces_buf(dst);
+    ff_htmlmarkup_to_ass(avctx, dst, in);
 }
 
 static int srt_decode_frame(AVCodecContext *avctx,