iptc.c

//--------------------------------------------------------------------------
//  Process IPTC data.
//--------------------------------------------------------------------------
#include "jhead.h"

// Supported IPTC entry types
#define IPTC_SUPLEMENTAL_CATEGORIES 0x14
#define IPTC_KEYWORDS               0x19
#define IPTC_CAPTION                0x78
#define IPTC_AUTHOR                 0x7A
#define IPTC_HEADLINE               0x69
#define IPTC_SPECIAL_INSTRUCTIONS   0x28
#define IPTC_CATEGORY               0x0F
#define IPTC_BYLINE                 0x50
#define IPTC_BYLINE_TITLE           0x55
#define IPTC_CREDIT                 0x6E
#define IPTC_SOURCE                 0x73
#define IPTC_COPYRIGHT_NOTICE       0x74
#define IPTC_OBJECT_NAME            0x05
#define IPTC_CITY                   0x5A
#define IPTC_STATE                  0x5F
#define IPTC_COUNTRY                0x65
#define IPTC_TRANSMISSION_REFERENCE 0x67
#define IPTC_DATE                   0x37
#define IPTC_COPYRIGHT              0x0A
#define IPTC_COUNTRY_CODE           0x64
#define IPTC_REFERENCE_SERVICE      0x2D

//--------------------------------------------------------------------------
//  Process and display IPTC marker.
//
//  IPTC block consists of:
//      - Marker:               1 byte      (0xED)
//      - Block length:         2 bytes
//      - IPTC Signature:       14 bytes    ("Photoshop 3.0\0")
//      - 8BIM Signature        4 bytes     ("8BIM")
//      - IPTC Block start      2 bytes     (0x04, 0x04)
//      - IPTC Header length    1 byte
//      - IPTC header           Header is padded to even length, counting the length byte
//      - Length                4 bytes
//      - IPTC Data which consists of a number of entries, each of which has the following format:
//              - Signature     2 bytes     (0x1C02)
//              - Entry type    1 byte      (for defined entry types, see #defines above)
//              - entry length  2 bytes
//              - entry data    'entry length' bytes
//
//--------------------------------------------------------------------------
void show_IPTC (unsigned char* Data, unsigned int itemlen)
{
    const char IptcSig1[] = "Photoshop 3.0";
    const char IptcSig2[] = "8BIM";
    const char IptcSig3[] = {0x04, 0x04};

    unsigned char * pos    = Data + sizeof(short);   // position data pointer after length field
    unsigned char * maxpos = Data+itemlen;
    char  headerLen = 0;

    if (itemlen < 25) goto corrupt;

    // Check IPTC signatures
    if (memcmp(pos, IptcSig1, sizeof(IptcSig1)-1) != 0) goto badsig;
    pos += sizeof(IptcSig1);      // move data pointer to the next field

    if (memcmp(pos, IptcSig2, sizeof(IptcSig2)-1) != 0) goto badsig;
    pos += sizeof(IptcSig2)-1;          // move data pointer to the next field

    if (memcmp(pos, IptcSig3, sizeof(IptcSig3)) != 0){
badsig:
        if (ShowTags){
            ErrNonfatal("IPTC type signature mismatch\n",0,0);
        }
        return;
    }
    pos += sizeof(IptcSig3);          // move data pointer to the next field

    if (pos >= maxpos) goto corrupt;

    // IPTC section found

    // Skip header
    headerLen = *pos++;                     // get header length and move data pointer to the next field
    pos += headerLen + 1 - (headerLen % 2); // move data pointer to the next field (Header is padded to even length, counting the length byte)

    if (pos+4 >= maxpos) goto corrupt;

    // Get length (from motorola format)
    //length = (*pos << 24) | (*(pos+1) << 16) | (*(pos+2) << 8) | *(pos+3);

    pos += sizeof(long);                    // move data pointer to the next field

    printf("======= IPTC data: =======\n");

    // Now read IPTC data
    while (pos < (Data + itemlen-5)) {
        short  signature;
        char   type = 0;
        short  length = 0;
        char * description = NULL;

        if (pos+5 > maxpos) goto corrupt;

        signature = (*pos << 8) + (*(pos+1));
        pos += sizeof(short);

        if (signature != 0x1C02){
            break;
        }

        type    = *pos++;
        length  = (*pos << 8) + (*(pos+1));
        pos    += sizeof(short);                // Skip tag length

        if (pos+length > maxpos) goto corrupt;
        // Process tag here
        switch (type) {
            case IPTC_SUPLEMENTAL_CATEGORIES:  description = "SuplementalCategories"; break;
            case IPTC_KEYWORDS:                description = "Keywords"; break;
            case IPTC_CAPTION:                 description = "Caption"; break;
            case IPTC_AUTHOR:                  description = "Author"; break;
            case IPTC_HEADLINE:                description = "Headline"; break;
            case IPTC_SPECIAL_INSTRUCTIONS:    description = "Spec.Instr."; break;
            case IPTC_CATEGORY:                description = "Category"; break;
            case IPTC_BYLINE:                  description = "Byline"; break;
            case IPTC_BYLINE_TITLE:            description = "BylineTitle"; break;
            case IPTC_CREDIT:                  description = "Credit"; break;
            case IPTC_SOURCE:                  description = "Source"; break;
            case IPTC_COPYRIGHT_NOTICE:        description = "(C)Notice"; break;
            case IPTC_OBJECT_NAME:             description = "ObjectName"; break;
            case IPTC_CITY:                    description = "City"; break;
            case IPTC_STATE:                   description = "State"; break;
            case IPTC_COUNTRY:                 description = "Country"; break;
            case IPTC_TRANSMISSION_REFERENCE:  description = "OriginalTransmissionReference"; break;
            case IPTC_DATE:                    description = "DateCreated"; break;
            case IPTC_COPYRIGHT:               description = "(C)Flag"; break;
            case IPTC_REFERENCE_SERVICE:       description = "CountryCode"; break;
            case IPTC_COUNTRY_CODE:            description = "Ref.Service"; break;
            default:
                if (ShowTags){
                    printf("Unrecognised IPTC tag: 0x%02x \n", type);
                }
            break;
        }
        if (description != NULL) {
            char TempBuf[32];
            memset(TempBuf, 0, sizeof(TempBuf));
            memset(TempBuf, ' ', 13);
            memcpy(TempBuf, description, strlen(description));
            strcat(TempBuf, ":"); 
            printf("%s %*.*s\n", TempBuf, length, length, pos);
        }
        pos += length;
    }
    return;
corrupt:
    ErrNonfatal("Pointer corruption in IPTC\n",0,0);
}