Dan Fandrich's gzip patch applied

1 files changed, 235 insertions, 1 deletions

diff --git a/lib/content_encoding.c b/lib/content_encoding.c
index 5abb6e8cf..84240ea34 100644
--- a/lib/content_encoding.c
+++ b/lib/content_encoding.c
@@ -25,6 +25,9 @@
 
 #ifdef HAVE_LIBZ
 
+#include <stdlib.h>
+#include <string.h>
+
 #include "urldata.h"
 #include <curl/curl.h>
 #include <curl/types.h>
@@ -32,6 +35,16 @@
 
 #define DSIZ 4096               /* buffer size for decompressed data */
 
+#define GZIP_MAGIC_0 0x1f
+#define GZIP_MAGIC_1 0x8b
+
+/* gzip flag byte */
+#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
+#define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
+#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
+#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
+#define COMMENT      0x10 /* bit 4 set: file comment present */
+#define RESERVED     0xE0 /* bits 5..7: reserved */
 
 static CURLcode
 process_zlib_error(struct SessionHandle *data, z_stream *z)
@@ -74,7 +87,7 @@ Curl_unencode_deflate_write(struct SessionHandle *data,
     k->zlib_init = 1;
   }
 
-  /* Set the compressed input when this fucntion is called */
+  /* Set the compressed input when this function is called */
   z->next_in = (Bytef *)k->str;
   z->avail_in = nread;
 
@@ -111,4 +124,225 @@ Curl_unencode_deflate_write(struct SessionHandle *data,
     }
   }
 }
+
+/* Skip over the gzip header */
+static enum {
+  GZIP_OK,
+  GZIP_BAD,
+  GZIP_UNDERFLOW
+}
+check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen)
+{
+  int method, flags;
+  const ssize_t totallen = len;
+
+  /* The shortest header is 10 bytes */
+  if (len < 10)
+    return GZIP_UNDERFLOW;
+
+  if ((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1))
+    return GZIP_BAD;
+
+  method = data[2];
+  flags = data[3];
+
+  if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
+    /* Can't handle this compression method or unknown flag */
+    return GZIP_BAD;
+  }
+
+  /* Skip over time, xflags, OS code and all previous bytes */
+  len -= 10;
+  data += 10;
+
+  if (flags & EXTRA_FIELD) {
+    ssize_t extra_len;
+
+    if (len < 2)
+      return GZIP_UNDERFLOW;
+
+    extra_len = (data[1] << 8) | data[0];
+
+    if (len < (extra_len+2))
+      return GZIP_UNDERFLOW;
+
+    len -= (extra_len + 2);
+  }
+
+  if (flags & ORIG_NAME) {
+    /* Skip over NUL-terminated file name */
+    while (len && *data) {
+      --len;
+      ++data;
+    }
+    if (!len || *data)
+      return GZIP_UNDERFLOW;
+
+    /* Skip over the NUL */
+    --len;
+    ++data;
+  }
+
+  if (flags & COMMENT) {
+    /* Skip over NUL-terminated comment */
+    while (len && *data) {
+      --len;
+      ++data;
+    }
+    if (!len || *data)
+      return GZIP_UNDERFLOW;
+
+    /* Skip over the NUL */
+    --len;
+    ++data;
+  }
+
+  if (flags & HEAD_CRC) {
+    if (len < 2)
+      return GZIP_UNDERFLOW;
+
+    len -= 2;
+    data += 2;
+  }
+
+  *headerlen = totallen - len;
+  return GZIP_OK;
+}
+
+CURLcode
+Curl_unencode_gzip_write(struct SessionHandle *data, 
+                         struct Curl_transfer_keeper *k,
+                         ssize_t nread)
+{
+  int status;                   /* zlib status */
+  int result;                   /* Curl_client_write status */
+  char decomp[DSIZ];            /* Put the decompressed data here. */
+  z_stream *z = &k->z;          /* zlib state structure */
+              
+  /* Initialize zlib? */
+  if (!k->zlib_init) {
+    z->zalloc = (alloc_func)Z_NULL;
+    z->zfree = (free_func)Z_NULL;
+    z->opaque = 0;              /* of dubious use 08/27/02 jhrg */
+    if (inflateInit2(z, -MAX_WBITS) != Z_OK)
+      return process_zlib_error(data, z);
+    k->zlib_init = 1;   /* Initial call state */
+  }
+
+  /* This next mess is to get around the potential case where there isn't
+  enough data passed in to skip over the gzip header.  If that happens,
+  we malloc a block and copy what we have then wait for the next call.  If
+  there still isn't enough (this is definitely a worst-case scenario), we
+  make the block bigger, copy the next part in and keep waiting. */
+
+  /* Skip over gzip header? */
+  if (k->zlib_init == 1) {
+    /* Initial call state */
+    ssize_t hlen;
+
+    switch (check_gzip_header((unsigned char *)k->str, nread, &hlen)) {
+    case GZIP_OK:
+      z->next_in = (Bytef *)k->str + hlen;
+      z->avail_in = nread - hlen;
+      k->zlib_init = 3; /* Inflating stream state */
+      break;
+
+    case GZIP_UNDERFLOW:
+      /* We need more data so we can find the end of the gzip header */
+      z->avail_in = nread;
+      z->next_in = malloc(z->avail_in);
+      if (z->next_in == NULL) {
+        return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY);
+      }
+      memcpy(z->next_in, k->str, z->avail_in);
+      k->zlib_init = 2;   /* Need more gzip header data state */
+      /* We don't have any data to inflate yet */
+      return CURLE_OK;
+
+    case GZIP_BAD:
+    default:
+      return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z));
+    }
+
+  }
+  else if (k->zlib_init == 2) {
+    /* Need more gzip header data state */
+    ssize_t hlen;
+    unsigned char *oldblock = z->next_in;
+
+    z->avail_in += nread;
+    z->next_in = realloc(z->next_in, z->avail_in);
+    if (z->next_in == NULL) {
+      free(oldblock);
+      return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY);
+    }
+    /* Append the new block of data to the previous one */
+    memcpy(z->next_in + z->avail_in - nread, k->str, nread);
+
+    switch (check_gzip_header(z->next_in, z->avail_in, &hlen)) {
+    case GZIP_OK:
+      /* This is the zlib stream data */
+      free(z->next_in);
+      /* Don't point into the malloced block since we just freed it */
+      z->next_in = (Bytef *)k->str + hlen + nread - z->avail_in;
+      z->avail_in = z->avail_in - hlen;
+      k->zlib_init = 3;   /* Inflating stream state */
+      break;
+
+    case GZIP_UNDERFLOW:
+      /* We still don't have any data to inflate! */
+      return CURLE_OK;
+
+    case GZIP_BAD:
+    default:
+      free(z->next_in);
+      return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z));
+    }
+
+  }
+  else {
+    /* Inflating stream state */
+    z->next_in = (Bytef *)k->str;
+    z->avail_in = nread;
+  }
+
+  if (z->avail_in == 0) {
+    /* We don't have any data to inflate; wait until next time */
+    return CURLE_OK;
+  }
+
+  /* because the buffer size is fixed, iteratively decompress
+     and transfer to the client via client_write. */
+  for (;;) {
+    /* (re)set buffer for decompressed output for every iteration */
+    z->next_out = (Bytef *)&decomp[0];
+    z->avail_out = DSIZ;
+
+    status = inflate(z, Z_SYNC_FLUSH);
+    if (status == Z_OK || status == Z_STREAM_END) {
+      result = Curl_client_write(data, CLIENTWRITE_BODY, decomp, 
+                                 DSIZ - z->avail_out);
+      /* if !CURLE_OK, clean up, return */
+      if (result) {              
+        return exit_zlib(z, &k->zlib_init, result);
+      }
+
+      /* Done?; clean up, return */
+      /* We should really check the gzip CRC here */
+      if (status == Z_STREAM_END) {
+        if (inflateEnd(z) == Z_OK)
+          return exit_zlib(z, &k->zlib_init, result);
+        else
+          return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z));
+      }
+
+      /* Done with these bytes, exit */
+      if (status == Z_OK && z->avail_in == 0 && z->avail_out > 0) 
+        return result;
+    }
+    else {                      /* Error; exit loop, handle below */
+      return exit_zlib(z, &k->zlib_init, process_zlib_error(data, z));
+    }
+  }
+}
 #endif /* HAVE_LIBZ */