adding bspatch_stream and updating readcompress to use it

diff --git a/bspatch.c b/bspatch.c
index 1f8e486..45ba36a 100644 (file)
--- a/bspatch.c
+++ b/bspatch.c
@@ -37,6 +37,12 @@ __FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:
 #include <unistd.h>
 #include <fcntl.h>
 
+struct bspatch_stream
+{
+       void* opaque;
+       int (*read)(const struct bspatch_stream* stream, void* buffer, int length);
+};
+
 struct bspatch_request
 {
        const uint8_t* old;
@@ -66,25 +72,33 @@ static int64_t offtin(uint8_t *buf)
        return y;
 }
 
-static const int BUFFER_SIZE = 4096;
+#define BUFFER_SIZE 4096
+struct bspatch_bz2_buffer
+{
+       FILE* pf;
+       bz_stream bz2;
+       char buffer[BUFFER_SIZE];
+};
 
-static int readcompress(bz_stream* bz2, FILE* pf, uint8_t* dest, int length)
+static int readcompress(const struct bspatch_stream* stream, void* buffer, int length)
 {
        int n;
        int ret;
+       struct bspatch_bz2_buffer* buf = (struct bspatch_bz2_buffer*)stream->opaque;
+       bz_stream* bz2 = &buf->bz2;
 
-       bz2->next_out = (char*)dest;
+       bz2->next_out = (char*)buffer;
        bz2->avail_out = length;
 
        for (;;)
        {
-               if (bz2->avail_in == 0 && !feof(pf) && bz2->avail_out > 0)
+               if (bz2->avail_in == 0 && !feof(buf->pf) && bz2->avail_out > 0)
                {
-                       n = fread(bz2->opaque, 1, BUFFER_SIZE, pf);
-                       if (ferror(pf))
+                       n = fread(buf->buffer, 1, BUFFER_SIZE, buf->pf);
+                       if (ferror(buf->pf))
                                return -1;
 
-                       bz2->next_in = bz2->opaque;
+                       bz2->next_in = buf->buffer;
                        bz2->avail_in = n;
                }
 
@@ -92,7 +106,7 @@ static int readcompress(bz_stream* bz2, FILE* pf, uint8_t* dest, int length)
                if (ret != BZ_OK && ret != BZ_STREAM_END)
                        return -1;
 
-               if (ret == BZ_OK && feof(pf) && bz2->avail_in == 0 && bz2->avail_out > 0)
+               if (ret == BZ_OK && feof(buf->pf) && bz2->avail_in == 0 && bz2->avail_out > 0)
                        return -1;
 
                if (ret == BZ_STREAM_END)
@@ -107,10 +121,12 @@ static int readcompress(bz_stream* bz2, FILE* pf, uint8_t* dest, int length)
 
 int bspatch(const struct bspatch_request req)
 {
-       bz_stream cbz2 = {0};
-       bz_stream dbz2 = {0};
-       bz_stream ebz2 = {0};
-       char cbuf[BUFFER_SIZE], dbuf[BUFFER_SIZE], ebuf[BUFFER_SIZE];
+       struct bspatch_stream cstream;
+       struct bspatch_stream dstream;
+       struct bspatch_stream estream;
+       struct bspatch_bz2_buffer cbz2 = {0};
+       struct bspatch_bz2_buffer dbz2 = {0};
+       struct bspatch_bz2_buffer ebz2 = {0};
        int cbz2err, dbz2err, ebz2err;
        uint8_t buf[8];
        int64_t oldpos,newpos;
@@ -118,22 +134,28 @@ int bspatch(const struct bspatch_request req)
        int64_t lenread;
        int64_t i;
 
-       cbz2.opaque = cbuf;
-       dbz2.opaque = dbuf;
-       ebz2.opaque = ebuf;
-
-       if (BZ_OK != (cbz2err = BZ2_bzDecompressInit(&cbz2, 0, 0)))
+       cbz2.pf = req.cpf;
+       cstream.opaque = &cbz2;
+       cstream.read = readcompress;
+       dbz2.pf = req.dpf;
+       dstream.opaque = &dbz2;
+       dstream.read = readcompress;
+       ebz2.pf = req.epf;
+       estream.opaque = &ebz2;
+       estream.read = readcompress;
+
+       if (BZ_OK != (cbz2err = BZ2_bzDecompressInit(&cbz2.bz2, 0, 0)))
                errx(1, "BZ2_bzDecompressInit, bz2err = %d", cbz2err);
-       if (BZ_OK != (dbz2err = BZ2_bzDecompressInit(&dbz2, 0, 0)))
+       if (BZ_OK != (dbz2err = BZ2_bzDecompressInit(&dbz2.bz2, 0, 0)))
                errx(1, "BZ2_bzDecompressInit, bz2err = %d", dbz2err);
-       if (BZ_OK != (ebz2err = BZ2_bzDecompressInit(&ebz2, 0, 0)))
+       if (BZ_OK != (ebz2err = BZ2_bzDecompressInit(&ebz2.bz2, 0, 0)))
                errx(1, "BZ2_bzDecompressInit, bz2err = %d", ebz2err);
 
        oldpos=0;newpos=0;
        while(newpos<req.newsize) {
                /* Read control data */
                for(i=0;i<=2;i++) {
-                       lenread = readcompress(&cbz2, req.cpf, buf, 8);
+                       lenread = cstream.read(&cstream, buf, 8);
                        if (lenread != 8)
                                errx(1, "Corrupt patch\n");
                        ctrl[i]=offtin(buf);
@@ -144,7 +166,7 @@ int bspatch(const struct bspatch_request req)
                        errx(1,"Corrupt patch\n");
 
                /* Read diff string */
-               lenread = readcompress(&dbz2, req.dpf, req.new + newpos, ctrl[0]);
+               lenread = dstream.read(&dstream, req.new + newpos, ctrl[0]);
                if (lenread != ctrl[0])
                        errx(1, "Corrupt patch\n");
 
@@ -162,7 +184,7 @@ int bspatch(const struct bspatch_request req)
                        errx(1,"Corrupt patch\n");
 
                /* Read extra string */
-               lenread = readcompress(&ebz2, req.epf, req.new + newpos, ctrl[1]);
+               lenread = estream.read(&estream, req.new + newpos, ctrl[1]);
                if (lenread != ctrl[1])
                        errx(1, "Corrupt patch\n");
 
@@ -172,9 +194,9 @@ int bspatch(const struct bspatch_request req)
        };
 
        /* Clean up the bzip2 reads */
-       BZ2_bzDecompressEnd(&cbz2);
-       BZ2_bzDecompressEnd(&dbz2);
-       BZ2_bzDecompressEnd(&ebz2);
+       BZ2_bzDecompressEnd(&cbz2.bz2);
+       BZ2_bzDecompressEnd(&dbz2.bz2);
+       BZ2_bzDecompressEnd(&ebz2.bz2);
 
        return 0;
 }