handling large file requests by breaking up calls to compressor->write

diff --git a/bsdiff.c b/bsdiff.c
index 1093241..8c373cb 100644 (file)
--- a/bsdiff.c
+++ b/bsdiff.c
@@ -49,6 +49,7 @@ struct bsdiff_compressor
 
 #if !defined(BSDIFF_HEADER_ONLY)
 
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -207,6 +208,27 @@ static void offtout(int64_t x,uint8_t *buf)
        if(x<0) buf[7]|=0x80;
 }
 
+static int64_t writecompressed(struct bsdiff_compressor* compressor, const void* buffer, int64_t length)
+{
+       int64_t result = 0;
+
+       while (length > 0)
+       {
+               const int smallsize = (int)MIN(length, INT_MAX);
+               const int writeresult = compressor->write(compressor, buffer, smallsize);
+               if (writeresult == -1)
+               {
+                       return -1;
+               }
+
+               result += writeresult;
+               length -= smallsize;
+               buffer = (uint8_t*)buffer + smallsize;
+       }
+
+       return result;
+}
+
 struct bsdiff_request
 {
        const uint8_t* old;
@@ -327,7 +349,7 @@ static int bsdiff_internal(const struct bsdiff_request req)
                        offtout((scan-lenb)-(lastscan+lenf),buf+8);
                        offtout((pos-lenb)-(lastpos+lenf),buf+16);
 
-                       compresslen = req.compressor->write(req.compressor, buf, sizeof(buf));
+                       compresslen = writecompressed(req.compressor, buf, sizeof(buf));
                        if (compresslen == -1)
                                return -1;
                        filelen += compresslen;
@@ -346,7 +368,7 @@ static int bsdiff_internal(const struct bsdiff_request req)
        req.header->ctrl_block_length = filelen;
 
        /* Write compressed diff data */
-       compresslen = req.compressor->write(req.compressor, db, dblen);
+       compresslen = writecompressed(req.compressor, db, dblen);
        if (compresslen == -1)
                return -1;
        filelen += compresslen;
@@ -359,7 +381,7 @@ static int bsdiff_internal(const struct bsdiff_request req)
        req.header->diff_block_length = filelen - req.header->ctrl_block_length;
 
        /* Write compressed extra data */
-       compresslen = req.compressor->write(req.compressor, eb, eblen);
+       compresslen = writecompressed(req.compressor, eb, eblen);
        if (compresslen == -1)
                return -1;
        compresslen = req.compressor->finish(req.compressor);