Declare source buffers in TurboJPEG C API as const

This reassures the caller that the buffers will not be modified and also
allows read-only buffers to be passed to the functions.

Partially reverts 3947a19f25fc8186d3812dbcf8e70baea36ef652.

ChangeLog.txt

@@ -25,6 +25,12 @@ negative width or height was used as an input image (Windows bitmaps can have
 a negative height if they are stored in top-down order, but such files are
 rare and not supported by libjpeg-turbo.)
 
+[6] Source buffers for the TurboJPEG C API functions, as well as the
+jpeg_mem_src() function in the libjpeg API, are now declared as const pointers.
+This facilitates passing read-only buffers to those functions and ensures the
+caller that the source buffer will not be modified.  This should not create any
+backward API or ABI incompatibilities with prior libjpeg-turbo releases.
+
 
 1.4.1
 =====

doc/html/search/functions_74.js

@@ -3,18 +3,18 @@ var searchData=
   ['tjalloc',['tjAlloc',['../group___turbo_j_p_e_g.html#ga5c9234bda6d993cdaffdd89bf81a00ff',1,'turbojpeg.h']]],
   ['tjbufsize',['tjBufSize',['../group___turbo_j_p_e_g.html#gaccc5bca7f12fcdcc302e6e1c6d4b311b',1,'turbojpeg.h']]],
   ['tjbufsizeyuv2',['tjBufSizeYUV2',['../group___turbo_j_p_e_g.html#gaf451664a62c1f6c7cc5a6401f32908c9',1,'turbojpeg.h']]],
-  ['tjcompress2',['tjCompress2',['../group___turbo_j_p_e_g.html#gaba62b7a98f960839b588579898495cf2',1,'turbojpeg.h']]],
-  ['tjcompressfromyuv',['tjCompressFromYUV',['../group___turbo_j_p_e_g.html#ga0b931126c7a615ddc3bbd0cca6698d67',1,'turbojpeg.h']]],
-  ['tjcompressfromyuvplanes',['tjCompressFromYUVPlanes',['../group___turbo_j_p_e_g.html#gaa89a1982cb4556b12ae7af4439991af6',1,'turbojpeg.h']]],
-  ['tjdecodeyuv',['tjDecodeYUV',['../group___turbo_j_p_e_g.html#ga132ae2c2cadcf64c8bb0f3bdf69da3ed',1,'turbojpeg.h']]],
-  ['tjdecodeyuvplanes',['tjDecodeYUVPlanes',['../group___turbo_j_p_e_g.html#ga6cb5b0e1101a2b20edea576e11faf93d',1,'turbojpeg.h']]],
-  ['tjdecompress2',['tjDecompress2',['../group___turbo_j_p_e_g.html#gada69cc6443d1bb493b40f1626259e5e9',1,'turbojpeg.h']]],
-  ['tjdecompressheader3',['tjDecompressHeader3',['../group___turbo_j_p_e_g.html#gacd0fac3af74b3511d39b4781b7103086',1,'turbojpeg.h']]],
-  ['tjdecompresstoyuv2',['tjDecompressToYUV2',['../group___turbo_j_p_e_g.html#ga7c08b340ad7f8e85d407bd9e81d44d07',1,'turbojpeg.h']]],
-  ['tjdecompresstoyuvplanes',['tjDecompressToYUVPlanes',['../group___turbo_j_p_e_g.html#ga0828a38ae29631ac28b6857cefb0eebf',1,'turbojpeg.h']]],
+  ['tjcompress2',['tjCompress2',['../group___turbo_j_p_e_g.html#gaf38f2ed44bdc88e730e08b632fa6e88e',1,'turbojpeg.h']]],
+  ['tjcompressfromyuv',['tjCompressFromYUV',['../group___turbo_j_p_e_g.html#ga6f6de375d6ec0020faba627e37e5a060',1,'turbojpeg.h']]],
+  ['tjcompressfromyuvplanes',['tjCompressFromYUVPlanes',['../group___turbo_j_p_e_g.html#ga0b84c682d8accf097d7a743c965d3464',1,'turbojpeg.h']]],
+  ['tjdecodeyuv',['tjDecodeYUV',['../group___turbo_j_p_e_g.html#ga077c61027b875afecd5a1613bf18b3c1',1,'turbojpeg.h']]],
+  ['tjdecodeyuvplanes',['tjDecodeYUVPlanes',['../group___turbo_j_p_e_g.html#gaf42f19b7a496eb18bdc84fe61ee6d3e2',1,'turbojpeg.h']]],
+  ['tjdecompress2',['tjDecompress2',['../group___turbo_j_p_e_g.html#gad8026a417e16a76313bc0a6c9e8b2ba2',1,'turbojpeg.h']]],
+  ['tjdecompressheader3',['tjDecompressHeader3',['../group___turbo_j_p_e_g.html#ga3fced455e504e8ff4fbad28ba94a3020',1,'turbojpeg.h']]],
+  ['tjdecompresstoyuv2',['tjDecompressToYUV2',['../group___turbo_j_p_e_g.html#ga39e08906528db5a764670ea48d344b09',1,'turbojpeg.h']]],
+  ['tjdecompresstoyuvplanes',['tjDecompressToYUVPlanes',['../group___turbo_j_p_e_g.html#ga38d0ef90692663b3ffb5b16da2541512',1,'turbojpeg.h']]],
   ['tjdestroy',['tjDestroy',['../group___turbo_j_p_e_g.html#ga674adee917b95ad4a896f1ba39e12540',1,'turbojpeg.h']]],
-  ['tjencodeyuv3',['tjEncodeYUV3',['../group___turbo_j_p_e_g.html#ga0a5ffbf7cb58a5b6a8201114fe889360',1,'turbojpeg.h']]],
-  ['tjencodeyuvplanes',['tjEncodeYUVPlanes',['../group___turbo_j_p_e_g.html#gaa791db8598853ddcad24e42897ef1269',1,'turbojpeg.h']]],
+  ['tjencodeyuv3',['tjEncodeYUV3',['../group___turbo_j_p_e_g.html#gaabe05acd734990053ad1294b5ef239aa',1,'turbojpeg.h']]],
+  ['tjencodeyuvplanes',['tjEncodeYUVPlanes',['../group___turbo_j_p_e_g.html#ga8a65ed3bd12df57c219d46afbc9008f1',1,'turbojpeg.h']]],
   ['tjfree',['tjFree',['../group___turbo_j_p_e_g.html#ga8c4a1231dc06a450514c835f6471f137',1,'turbojpeg.h']]],
   ['tjgeterrorstr',['tjGetErrorStr',['../group___turbo_j_p_e_g.html#ga9af79c908ec131b1ae8d52fe40375abf',1,'turbojpeg.h']]],
   ['tjgetscalingfactors',['tjGetScalingFactors',['../group___turbo_j_p_e_g.html#ga6449044b9af402999ccf52f401333be8',1,'turbojpeg.h']]],
@@ -24,5 +24,5 @@ var searchData=
   ['tjplaneheight',['tjPlaneHeight',['../group___turbo_j_p_e_g.html#ga1a209696c6a80748f20e134b3c64789f',1,'turbojpeg.h']]],
   ['tjplanesizeyuv',['tjPlaneSizeYUV',['../group___turbo_j_p_e_g.html#ga6f98d977bfa9d167c97172e876ba61e2',1,'turbojpeg.h']]],
   ['tjplanewidth',['tjPlaneWidth',['../group___turbo_j_p_e_g.html#ga63fb66bb1e36c74008c4634360becbb1',1,'turbojpeg.h']]],
-  ['tjtransform',['tjTransform',['../group___turbo_j_p_e_g.html#gae403193ceb4aafb7e0f56ab587b48616',1,'turbojpeg.h']]]
+  ['tjtransform',['tjTransform',['../group___turbo_j_p_e_g.html#gad02cd42b69f193a0623a9c801788df3a',1,'turbojpeg.h']]]
 ];

doc/html/structtjtransform.html

@@ -133,7 +133,7 @@
     <tr><td class="paramname">arrayRegion</td><td><a class="el" href="structtjregion.html" title="Cropping region.">tjregion</a> structure containing the width and height of the array pointed to by <code>coeffs</code> as well as its offset relative to the component plane. TurboJPEG implementations may choose to split each component plane into multiple DCT coefficient arrays and call the callback function once for each array.</td></tr>
     <tr><td class="paramname">planeRegion</td><td><a class="el" href="structtjregion.html" title="Cropping region.">tjregion</a> structure containing the width and height of the component plane to which <code>coeffs</code> belongs</td></tr>
     <tr><td class="paramname">componentID</td><td>ID number of the component plane to which <code>coeffs</code> belongs (Y, Cb, and Cr have, respectively, ID's of 0, 1, and 2 in typical JPEG images.)</td></tr>
-    <tr><td class="paramname">transformID</td><td>ID number of the transformed image to which <code>coeffs</code> belongs. This is the same as the index of the transform in the <code>transforms</code> array that was passed to <a class="el" href="group___turbo_j_p_e_g.html#gae403193ceb4aafb7e0f56ab587b48616" title="Losslessly transform a JPEG image into another JPEG image.">tjTransform()</a>.</td></tr>
+    <tr><td class="paramname">transformID</td><td>ID number of the transformed image to which <code>coeffs</code> belongs. This is the same as the index of the transform in the <code>transforms</code> array that was passed to <a class="el" href="group___turbo_j_p_e_g.html#gad02cd42b69f193a0623a9c801788df3a" title="Losslessly transform a JPEG image into another JPEG image.">tjTransform()</a>.</td></tr>
     <tr><td class="paramname">transform</td><td>a pointer to a <a class="el" href="structtjtransform.html" title="Lossless transform.">tjtransform</a> structure that specifies the parameters and/or cropping region for this transform</td></tr>
   </table>
   </dd>

jdatasrc-tj.c

@@ -157,7 +157,7 @@ term_source (j_decompress_ptr cinfo)
 
 GLOBAL(void)
 jpeg_mem_src_tj (j_decompress_ptr cinfo,
-              unsigned char * inbuffer, unsigned long insize)
+                 const unsigned char * inbuffer, unsigned long insize)
 {
   struct jpeg_source_mgr * src;
 
@@ -181,5 +181,5 @@ jpeg_mem_src_tj (j_decompress_ptr cinfo,
   src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
   src->term_source = term_source;
   src->bytes_in_buffer = (size_t) insize;
-  src->next_input_byte = (JOCTET *) inbuffer;
+  src->next_input_byte = (const JOCTET *) inbuffer;
 }

turbojpeg-jni.c

@@ -291,7 +291,8 @@ JNIEXPORT jint JNICALL Java_org_libjpegturbo_turbojpeg_TJCompressor_compressFrom
 	tjhandle handle=0;
 	unsigned long jpegSize=0;
 	jbyteArray jSrcPlanes[3]={NULL, NULL, NULL};
-	unsigned char *srcPlanes[3], *jpegBuf=NULL;
+	const unsigned char *srcPlanes[3];
+	unsigned char *jpegBuf=NULL;
 	int *srcOffsets=NULL, *srcStrides=NULL;
 	int nc=(subsamp==org_libjpegturbo_turbojpeg_TJ_SAMP_GRAY? 1:3), i;
 
@@ -349,8 +350,8 @@ JNIEXPORT jint JNICALL Java_org_libjpegturbo_turbojpeg_TJCompressor_compressFrom
 	for(i=0; i<nc; i++)
 	{
 		if(srcPlanes[i] && jSrcPlanes[i])
-			(*env)->ReleasePrimitiveArrayCritical(env, jSrcPlanes[i], srcPlanes[i],
-				0);
+			(*env)->ReleasePrimitiveArrayCritical(env, jSrcPlanes[i],
+				(unsigned char *)srcPlanes[i], 0);
 	}
 	if(srcStrides)
 		(*env)->ReleasePrimitiveArrayCritical(env, jSrcStrides, srcStrides, 0);
@@ -449,7 +450,7 @@ JNIEXPORT void JNICALL Java_org_libjpegturbo_turbojpeg_TJCompressor_encodeYUV___
 /* TurboJPEG 1.4.x: TJCompressor::encodeYUV() int source */
 JNIEXPORT void JNICALL Java_org_libjpegturbo_turbojpeg_TJCompressor_encodeYUV___3IIIIIII_3_3B_3I_3III
 	(JNIEnv *env, jobject obj, jintArray src, jint x, jint y, jint width,
-		jint stride, jint height, jint pf, jobjectArray dstobjs, 
+		jint stride, jint height, jint pf, jobjectArray dstobjs,
 		jintArray jDstOffsets, jintArray jDstStrides, jint subsamp, jint flags)
 {
 	if(pf<0 || pf>=org_libjpegturbo_turbojpeg_TJ_NUMPF)
@@ -847,7 +848,8 @@ static void TJDecompressor_decodeYUV
 	tjhandle handle=0;
 	jsize arraySize=0, actualPitch;
 	jbyteArray jSrcPlanes[3]={NULL, NULL, NULL};
-	unsigned char *srcPlanes[3], *dstBuf=NULL;
+	const unsigned char *srcPlanes[3];
+	unsigned char *dstBuf=NULL;
 	int *srcOffsets=NULL, *srcStrides=NULL;
 	int nc=(subsamp==org_libjpegturbo_turbojpeg_TJ_SAMP_GRAY? 1:3), i;
 
@@ -907,8 +909,8 @@ static void TJDecompressor_decodeYUV
 	for(i=0; i<nc; i++)
 	{
 		if(srcPlanes[i] && jSrcPlanes[i])
-			(*env)->ReleasePrimitiveArrayCritical(env, jSrcPlanes[i], srcPlanes[i],
-				0);
+			(*env)->ReleasePrimitiveArrayCritical(env, jSrcPlanes[i],
+				(unsigned char *)srcPlanes[i], 0);
 	}
 	if(srcStrides)
 		(*env)->ReleasePrimitiveArrayCritical(env, jSrcStrides, srcStrides, 0);