add a one-argument version of package_extract_file

Add a version of package_extract_file that returns the file data as
its return value (to be consumed by some other edify function that
expects to receive a bunch of binary data as an argument).  Lets us
avoid having two copies of a big file in memory (extracting it into
/tmp, which is a ramdisk, and then having something load it into
memory) when doing things like radio updates.

Change-Id: Ie26ece5fbae457eb0ddcd8a13d74d78a769fbc70

2 files changed, 44 insertions, 0 deletions

diff --git a/minzip/Zip.c b/minzip/Zip.c
index 8cdb898..46d2f82 100644
--- a/minzip/Zip.c
+++ b/minzip/Zip.c
@@ -810,6 +810,43 @@ bool mzExtractZipEntryToFile(const ZipArchive *pArchive,
     return true;
 }
 
+typedef struct {
+    unsigned char* buffer;
+    long len;
+} BufferExtractCookie;
+
+static bool bufferProcessFunction(const unsigned char *data, int dataLen,
+    void *cookie) {
+    BufferExtractCookie *bec = (BufferExtractCookie*)cookie;
+
+    memmove(bec->buffer, data, dataLen);
+    bec->buffer += dataLen;
+    bec->len -= dataLen;
+
+    return true;
+}
+
+/*
+ * Uncompress "pEntry" in "pArchive" to buffer, which must be large
+ * enough to hold mzGetZipEntryUncomplen(pEntry) bytes.
+ */
+bool mzExtractZipEntryToBuffer(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, unsigned char *buffer)
+{
+    BufferExtractCookie bec;
+    bec.buffer = buffer;
+    bec.len = mzGetZipEntryUncompLen(pEntry);
+
+    bool ret = mzProcessZipEntryContents(pArchive, pEntry,
+        bufferProcessFunction, (void*)&bec);
+    if (!ret || bec.len != 0) {
+        LOGE("Can't extract entry to memory buffer.\n");
+        return false;
+    }
+    return true;
+}
+
+
 /* Helper state to make path translation easier and less malloc-happy.
  */
 typedef struct {
diff --git a/minzip/Zip.h b/minzip/Zip.h
index 1c1df2f..9f99fba 100644
--- a/minzip/Zip.h
+++ b/minzip/Zip.h
@@ -169,6 +169,13 @@ bool mzExtractZipEntryToFile(const ZipArchive *pArchive,
     const ZipEntry *pEntry, int fd);
 
 /*
+ * Inflate and write an entry to a memory buffer, which must be long
+ * enough to hold mzGetZipEntryUncomplen(pEntry) bytes.
+ */
+bool mzExtractZipEntryToBuffer(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, unsigned char* buffer);
+
+/*
  * Inflate all entries under zipDir to the directory specified by
  * targetDir, which must exist and be a writable directory.
  *