support flateDecode stream filter

1 files changed, 87 insertions, 4 deletions

diff --git a/src/cos_stream_filter.c b/src/cos_stream_filter.c
index 6f407de..0c08442 100644
--- a/src/cos_stream_filter.c
+++ b/src/cos_stream_filter.c
@@ -13,21 +13,104 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <zlib.h>
 
 #include <nspdf/errors.h>
 
 #include "cos_object.h"
 #include "pdf_doc.h"
 
+static nspdferror
+cos_stream_inflate(struct nspdf_doc *doc, struct cos_stream **stream_out)
+{
+    int ret;
+    z_stream strm;
+    struct cos_stream *stream_in;
+    struct cos_stream *stream_res;
+
+    stream_in = *stream_out;
+
+    stream_res = calloc(1, sizeof(struct cos_stream));
+
+    //printf("inflating from %d bytes\n", stream_in->length);
+
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    strm.avail_in = 0;
+    strm.next_in = Z_NULL;
+
+    ret = inflateInit(&strm);
+    if (ret != Z_OK) {
+        return NSPDFERROR_NOTFOUND;
+    }
+
+    strm.next_in = (void *)stream_in->data;
+    strm.avail_in = stream_in->length;
+
+    do {
+        int64_t available; /* available buffer space for decompression */
+        available = stream_res->alloc - stream_res->length;
+
+        if (available < (strm.avail_in << 1)) {
+            uint8_t *newdata;
+            size_t newlength;
+
+            newlength = stream_res->alloc + (stream_in->length << 1);
+            newdata = realloc((void *)stream_res->data, newlength);
+            if (newdata == NULL) {
+                free((void *)stream_res->data);
+                free(stream_res);
+                inflateEnd(&strm);
+                return NSPDFERROR_NOMEM;
+            }
+
+            //printf("realloc %d\n", newlength);
+
+            stream_res->data = newdata;
+            stream_res->alloc = newlength;
+            available = stream_res->alloc - stream_res->length;
+        }
+
+        strm.avail_out = available;
+        strm.next_out = (void*)(stream_res->data + stream_res->length);
+        ret = inflate(&strm, Z_NO_FLUSH);
+        /** \todo check zlib return code */
+
+        stream_res->length += (available - strm.avail_out);
+
+    } while (ret != Z_STREAM_END);
+
+    //printf("allocated %d\n", stream_res->alloc);
+
+    //printf("length %d\n", stream_res->length);
+
+    inflateEnd(&strm);
+
+    if (stream_in->alloc != 0) {
+        free((void*)stream_in->data);
+    }
+    free(stream_in);
+
+    *stream_out = stream_res;
+
+    return NSPDFERROR_OK;
+}
+
 nspdferror
 nspdf__cos_stream_filter(struct nspdf_doc *doc,
                          const char *filter_name,
                          struct cos_stream **stream_out)
 {
-    struct cos_stream *stream_in;
+    nspdferror res;
 
-    stream_in = *stream_out;
+    //printf("applying filter %s\n", filter_name);
 
-    printf("applying filter %s\n", filter_name);
-    return NSPDFERROR_OK;
+    if (strcmp(filter_name, "FlateDecode") == 0) {
+        res = cos_stream_inflate(doc, stream_out);
+    } else {
+        res = NSPDFERROR_NOTFOUND;
+    }
+
+    return res;
 }