/*****************************************************************************

giftext - dump GIF pixels and metadata as text

SPDX-License-Identifier: MIT

*****************************************************************************/

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <fcntl.h>
#include <stdbool.h>

#ifdef _WIN32
#include <io.h>
#endif /* _WIN32 */

#include "gif_lib.h"
#include "getarg.h"

#define PROGRAM_NAME	"giftext"

#define MAKE_PRINTABLE(c)  (isprint(c) ? (c) : ' ')

static char
    *VersionStr =
	PROGRAM_NAME
	VERSION_COOKIE
	"	Gershon Elber,	"
	__DATE__ ",   " __TIME__ "\n"
	"(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr =
	PROGRAM_NAME
	" v%- c%- e%- z%- p%- r%- h%- GifFile!*s";

static void PrintCodeBlock(GifFileType *GifFile, GifByteType *CodeBlock, bool Reset);
static void PrintPixelBlock(GifByteType *PixelBlock, int Len, bool Reset);
static void PrintExtBlock(GifByteType *Extension, bool Reset);
static void PrintLZCodes(GifFileType *GifFile);

/******************************************************************************
 Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv)
{
    int i, j, ExtCode, ErrorCode, CodeSize, NumFiles, Len, ImageNum = 1;
    bool Error,
	ColorMapFlag = false, EncodedFlag = false, LZCodesFlag = false,
	PixelFlag = false, HelpFlag = false, RawFlag = false; 
    char *GifFileName, **FileName = NULL;
    GifPixelType *Line;
    GifRecordType RecordType;
    GifByteType *CodeBlock, *Extension;
    GifFileType *GifFile;

    if ((Error = GAGetArgs(argc, argv, CtrlStr,
		&GifNoisyPrint, &ColorMapFlag, &EncodedFlag,
		&LZCodesFlag, &PixelFlag, &RawFlag, &HelpFlag,
		&NumFiles, &FileName)) != false ||
	(NumFiles > 1 && !HelpFlag)) {
	if (Error)
	    GAPrintErrMsg(Error);
	else if (NumFiles > 1)
	    GIF_MESSAGE("Error in command line parsing - one GIF file please.");
	GAPrintHowTo(CtrlStr);
	exit(EXIT_FAILURE);
    }

    if (HelpFlag) {
	(void)fprintf(stderr, VersionStr, GIFLIB_MAJOR, GIFLIB_MINOR);
	GAPrintHowTo(CtrlStr);
	exit(EXIT_SUCCESS);
    }

    if (NumFiles == 1) {
	GifFileName = *FileName;
	if ((GifFile = DGifOpenFileName(*FileName, &ErrorCode)) == NULL) {
	    PrintGifError(ErrorCode);
	    exit(EXIT_FAILURE);
	}
    }
    else {
	/* Use stdin instead: */
	GifFileName = "Stdin";
	if ((GifFile = DGifOpenFileHandle(0, &ErrorCode)) == NULL) {
	    PrintGifError(ErrorCode);
	    exit(EXIT_FAILURE);
	}
    }

    /* Because we write binary data - make sure no text will be written. */
    if (RawFlag) {
	ColorMapFlag = EncodedFlag = LZCodesFlag = PixelFlag = false;
#ifdef _WIN32
	_setmode(1, O_BINARY);             /* Make sure it is in binary mode. */
#endif /* _WIN32 */
    }
    else {
	printf("\n%s:\n\n\tScreen Size - Width = %d, Height = %d.\n",
	       GifFileName, GifFile->SWidth, GifFile->SHeight);
	printf("\tColorResolution = %d, BitsPerPixel = %d, BackGround = %d, Aspect = %d.\n",
	       GifFile->SColorResolution,
	       GifFile->SColorMap ? GifFile->SColorMap->BitsPerPixel : 0,
	       GifFile->SBackGroundColor,
	       GifFile->AspectByte);
	if (GifFile->SColorMap)
	    printf("\tHas Global Color Map.\n\n");
	else
	    printf("\tNo Global Color Map.\n\n");
	if (ColorMapFlag && GifFile->SColorMap) {
	    printf("\tGlobal Color Map:\n");
	    Len = GifFile->SColorMap->ColorCount;
	    printf("\tSort Flag: %s\n", 
		   GifFile->SColorMap->SortFlag ? "on":"off");
	    for (i = 0; i < Len; i+=4) {
		for (j = 0; j < 4 && j < Len; j++) {
		    printf("%3d: %02xh %02xh %02xh   ", i + j,
			   GifFile->SColorMap->Colors[i + j].Red,
			   GifFile->SColorMap->Colors[i + j].Green,
			   GifFile->SColorMap->Colors[i + j].Blue);
		}
		printf("\n");
	    }
	}
    }

    do {
	if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR) {
	    PrintGifError(GifFile->Error);
	    exit(EXIT_FAILURE);
	}
	switch (RecordType) {
	    case IMAGE_DESC_RECORD_TYPE:
		if (DGifGetImageDesc(GifFile) == GIF_ERROR) {
		    PrintGifError(GifFile->Error);
		    exit(EXIT_FAILURE);
		}
		if (!RawFlag) {
		    printf("\nImage #%d:\n\n\tImage Size - Left = %d, Top = %d, Width = %d, Height = %d.\n",
			   ImageNum++, GifFile->Image.Left, GifFile->Image.Top,
			   GifFile->Image.Width, GifFile->Image.Height);
		    printf("\tImage is %s",
			   GifFile->Image.Interlace ? "Interlaced" :
						    "Non Interlaced");
		    if (GifFile->Image.ColorMap != NULL)
			printf(", BitsPerPixel = %d.\n",
				GifFile->Image.ColorMap->BitsPerPixel);
		    else
			printf(".\n");
		    if (GifFile->Image.ColorMap)
			printf("\tImage Has Color Map.\n");
		    else
			printf("\tNo Image Color Map.\n");
		    if (ColorMapFlag && GifFile->Image.ColorMap) {
			printf("\tSort Flag: %s\n", 
			       GifFile->Image.ColorMap->SortFlag ? "on":"off");
			Len = 1 << GifFile->Image.ColorMap->BitsPerPixel;
			for (i = 0; i < Len; i+=4) {
			    for (j = 0; j < 4 && j < Len; j++) {
				printf("%3d: %02xh %02xh %02xh   ", i + j,
				       GifFile->Image.ColorMap->Colors[i + j].Red,
				       GifFile->Image.ColorMap->Colors[i + j].Green,
				       GifFile->Image.ColorMap->Colors[i + j].Blue);
			    }
			    printf("\n");
			}
		    }
		}

		if (EncodedFlag) {
		    if (DGifGetCode(GifFile, &CodeSize, &CodeBlock) == GIF_ERROR) {
			PrintGifError(GifFile->Error);
			exit(EXIT_FAILURE);
		    }
		    printf("\nImage LZ compressed Codes (Code Size = %d):\n",
			   CodeSize);
		    PrintCodeBlock(GifFile, CodeBlock, true);
		    while (CodeBlock != NULL) {
			if (DGifGetCodeNext(GifFile, &CodeBlock) == GIF_ERROR) {
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
			PrintCodeBlock(GifFile, CodeBlock, false);
		    }
		}
		else if (LZCodesFlag) {
		    PrintLZCodes(GifFile);
		}
		else if (PixelFlag) {
		    Line = (GifPixelType *) malloc(GifFile->Image.Width *
						sizeof(GifPixelType));
		    for (i = 0; i < GifFile->Image.Height; i++) {
			if (DGifGetLine(GifFile, Line, GifFile->Image.Width)
			    == GIF_ERROR) {
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
			PrintPixelBlock(Line, GifFile->Image.Width, i == 0);
		    }
		    PrintPixelBlock(NULL, GifFile->Image.Width, false);
		    free((char *) Line);
		}
		else if (RawFlag) {
		    Line = (GifPixelType *) malloc(GifFile->Image.Width *
						sizeof(GifPixelType));
		    for (i = 0; i < GifFile->Image.Height; i++) {
			if (DGifGetLine(GifFile, Line, GifFile->Image.Width)
			    == GIF_ERROR) {
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
			fwrite(Line, 1, GifFile->Image.Width, stdout);
		    }
		    free((char *) Line);
		}
		else {
		    /* Skip the image: */
		    if (DGifGetCode(GifFile, &CodeSize, &CodeBlock) == GIF_ERROR) {
			PrintGifError(GifFile->Error);
			exit(EXIT_FAILURE);
		    }
		    while (CodeBlock != NULL) {
			if (DGifGetCodeNext(GifFile, &CodeBlock) == GIF_ERROR) {
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
		    }

		}
		break;
	    case EXTENSION_RECORD_TYPE:
		if (DGifGetExtension(GifFile, &ExtCode, &Extension) == GIF_ERROR) {
		    PrintGifError(GifFile->Error);
		    exit(EXIT_FAILURE);
		}
		if (!RawFlag) {
		    putchar('\n');
		    switch (ExtCode)
		    {
		    case COMMENT_EXT_FUNC_CODE:
			printf("GIF89 comment");
			break;
		    case GRAPHICS_EXT_FUNC_CODE:
			printf("GIF89 graphics control");
			break;
		    case PLAINTEXT_EXT_FUNC_CODE:
			printf("GIF89 plaintext");
			break;
		    case APPLICATION_EXT_FUNC_CODE:
			printf("GIF89 application block");
			break;
		    default:
			printf("Extension record of unknown type");
			break;
		    }
		    printf(" (Ext Code = %d [%c]):\n",
			   ExtCode, MAKE_PRINTABLE(ExtCode));
		    PrintExtBlock(Extension, true);

		    if (ExtCode == GRAPHICS_EXT_FUNC_CODE) {
			GraphicsControlBlock gcb;
			if (Extension == NULL) {
			    printf("Invalid extension block\n");
			    GifFile->Error = D_GIF_ERR_IMAGE_DEFECT;
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
			if (DGifExtensionToGCB(Extension[0], Extension+1, &gcb) == GIF_ERROR) {
			    PrintGifError(GifFile->Error);
			    exit(EXIT_FAILURE);
			}
			printf("\tDisposal Mode: %d\n", gcb.DisposalMode);
			printf("\tUser Input Flag: %d\n", gcb.UserInputFlag);
			printf("\tTransparency on: %s\n",
			       gcb.TransparentColor != -1 ? "yes" : "no");
			printf("\tDelayTime: %d\n", gcb.DelayTime);
			printf("\tTransparent Index: %d\n", gcb.TransparentColor);
		    }
		}
		for (;;) {
		    if (DGifGetExtensionNext(GifFile, &Extension) == GIF_ERROR) {
			PrintGifError(GifFile->Error);
			exit(EXIT_FAILURE);
		    }
		    if (Extension == NULL)
			break;
		    PrintExtBlock(Extension, false);
		}
		break;
	    case TERMINATE_RECORD_TYPE:
		break;
	    default:	     /* Should be trapped by DGifGetRecordType */
		break;
	}
    }
    while (RecordType != TERMINATE_RECORD_TYPE);

    if (DGifCloseFile(GifFile, &ErrorCode) == GIF_ERROR) {
	PrintGifError(ErrorCode);
	exit(EXIT_FAILURE);
    }

    if (!RawFlag) printf("\nGIF file terminated normally.\n");

    return 0;
}

/******************************************************************************
 Print the given CodeBlock - a string in pascal notation (size in first
 place). Save local information so printing can be performed continuously,
 or reset to start state if Reset. If CodeBlock is NULL, output is flushed
******************************************************************************/
static void PrintCodeBlock(GifFileType *GifFile, GifByteType *CodeBlock, bool Reset)
{
    static int CrntPlace = 0; 
    static long CodeCount = 0;
    int i, Len;

    if (Reset || CodeBlock == NULL) {
	if (CodeBlock == NULL) {
	    long NumBytes = 0;
	    if (CrntPlace > 0) {
		printf("\n");
		CodeCount += CrntPlace - 16;
	    }
	    if (GifFile->Image.ColorMap)
		NumBytes = ((((long) GifFile->Image.Width) * GifFile->Image.Height)
				* GifFile->Image.ColorMap->BitsPerPixel) / 8;
	    else if (GifFile->SColorMap != NULL)
		NumBytes = ((((long) GifFile->Image.Width) * GifFile->Image.Height)
				* GifFile->SColorMap->BitsPerPixel) / 8;
	    /* FIXME: What should the compression ratio be if no color table? */
	    if (NumBytes > 0) {
		int Percent = 100 * CodeCount / NumBytes;
		printf("\nCompression ratio: %ld/%ld (%d%%).\n",
			CodeCount, NumBytes, Percent);
	    }
	    return;
	}
	CrntPlace = 0;
	CodeCount = 0;
    }

    Len = CodeBlock[0];
    for (i = 1; i <= Len; i++) {
	if (CrntPlace == 0) {
	    printf("\n%05lxh:  ", CodeCount);
	    CodeCount += 16;
	}
	(void)printf(" %02xh", CodeBlock[i]);
	if (++CrntPlace >= 16) CrntPlace = 0;
    }
}

/******************************************************************************
 Print the given Extension - a string in pascal notation (size in first
 place). Save local information so printing can be performed continuously,
 or reset to start state if Reset. If Extension is NULL, output is flushed
******************************************************************************/
static void PrintExtBlock(GifByteType *Extension, bool Reset)
{
    static int CrntPlace = 0;
    static long ExtCount = 0;
    static char HexForm[49], AsciiForm[17];

    if (Reset || Extension == NULL) {
	if (Extension == NULL) {
	    if (CrntPlace > 0) {
		HexForm[CrntPlace * 3] = 0;
		AsciiForm[CrntPlace] = 0;
		printf("\n%05lx: %-49s  %-17s\n", ExtCount, HexForm, AsciiForm);
		return;
	    }
	    else
		printf("\n");
	}
	CrntPlace = 0;
	ExtCount = 0;
    }

    if (Extension != NULL) {
	int i, Len;
	Len = Extension[0];
	for (i = 1; i <= Len; i++) {
	    (void)snprintf(&HexForm[CrntPlace * 3], 3,
			   " %02x", Extension[i]);
	    (void)snprintf(&AsciiForm[CrntPlace], 3,
			   "%c", MAKE_PRINTABLE(Extension[i]));
	    if (++CrntPlace == 16) {
		HexForm[CrntPlace * 3] = 0;
		AsciiForm[CrntPlace] = 0;
		printf("\n%05lx: %-49s  %-17s", ExtCount, HexForm, AsciiForm);
		ExtCount += 16;
		CrntPlace = 0;
	    }
	}
    }
}

/******************************************************************************
 Print the given PixelBlock of length Len.
 Save local information so printing can be performed continuously,
 or reset to start state if Reset. If PixelBlock is NULL, output is flushed
******************************************************************************/
static void PrintPixelBlock(GifByteType *PixelBlock, int Len, bool Reset)
{
    static int CrntPlace = 0; 
    static long ExtCount = 0;
    static char HexForm[49], AsciiForm[17];
    int i;

    if (Reset || PixelBlock == NULL) {
	if (PixelBlock == NULL) {
	    if (CrntPlace > 0) {
		HexForm[CrntPlace * 3] = 0;
		AsciiForm[CrntPlace] = 0;
		printf("\n%05lx: %-49s  %-17s\n", ExtCount, HexForm, AsciiForm);
	    }
	    else
		printf("\n");
	}
	CrntPlace = 0;
	ExtCount = 0;
	if (PixelBlock == NULL) return;
    }

    for (i = 0; i < Len; i++) {
	(void)snprintf(&HexForm[CrntPlace * 3], 3,
		       " %02x", PixelBlock[i]);
	(void)snprintf(&AsciiForm[CrntPlace], 3,
		       "%c", MAKE_PRINTABLE(PixelBlock[i]));
	if (++CrntPlace == 16) {
	    HexForm[CrntPlace * 3] = 0;
	    AsciiForm[CrntPlace] = 0;
	    printf("\n%05lx: %-49s  %-17s", ExtCount, HexForm, AsciiForm);
	    ExtCount += 16;
	    CrntPlace = 0;
	}
    }
}

/******************************************************************************
 Print the image as LZ codes (each 12bits), until EOF marker is reached.
******************************************************************************/
static void PrintLZCodes(GifFileType *GifFile)
{
    int Code, CrntPlace = 0;
    long CodeCount = 0;

    do {
	if (CrntPlace == 0) printf("\n%05lx:", CodeCount);
	if (DGifGetLZCodes(GifFile, &Code) == GIF_ERROR) {
	    PrintGifError(GifFile->Error);
	    exit(EXIT_FAILURE);
	}
	if (Code >= 0)
	    printf(" %03x", Code);	      /* EOF Code is returned as -1. */
	CodeCount++;
	if (++CrntPlace >= 16) CrntPlace = 0;
    }
    while (Code >= 0);
}

/* end */